IRVM techniques were introduced to Iowa in the mid-1980s in response to the need to protect groundwater and surface water from herbicide contamination. Roadside weed control had previously relied exclusively on herbicides, with most counties employing blanket spraying (also known as “broadcast spraying”) to spray vast swaths of the roadside. 

Besides being expensive and potentially harmful, blanket spraying was unsustainable and ineffective. It created openings for weeds to grow by weakening roadside grasses and eliminating beneficial broadleaf species. 

At this time, the Iowa Department of Transportation started using native prairie grasses and wildflowers to control erosion and save money on mowing fuel since native plants require less mowing than cool-season grasses. A few county conservation boards were also experimenting with this naturally adapted alternative roadside vegetation. 

In 1988, the Iowa Legislature passed legislation adopting parameters for IRVM into state code. The program's cornerstone was native vegetation in Iowa roadsides. The Living Roadway Trust Fund (LRTF) was created the following year to support state, city, and county roadside projects. For more information about the history of IRVM and LRTF, see the 2018 report by Jean Eells, “Iowa’s Living Roadway Trust Fund and Integrated Roadside Vegetation Management Program.”

Goals

Basic Tenets 

The Road to Success for County Roadside Management

The Integrated Toolbox

The Benefits of Native Vegetation

Progress to Date

The Iowa Department of Transportation and half of Iowa’s counties routinely plant native vegetation and have reduced herbicide use to spot-spray application.

Since the early 1990s, native vegetation has been planted to over 40,000 acres of state and 35,000 acres of county road right-of-way. Diverse stands of 20–45 prairie grass and wildflower species—all naturally adapted to local growing conditions—provide stable, low-maintenance roadsides for Iowa.

As of late 2024, 61 counties had an IRVM plan and 47 counties had a roadside vegetation manager. Counties with either a plan or a roadside vegetation manager collectively managed 308,000 acres of roadside vegetation using IRVM principles. There were also 22 cities with an IRVM plan.

The Challenge

Reaching the goal of having a higher percentage of counties and cities prioritize roadside vegetation is challenging, primarily because officials prioritize addressing other issues rather than considering how their roadside vegetation could be managed differently.

According to the 2020 Federal Land Ownership Report, of Iowa’s total land area of 35,860,480 acres (56,273 square miles), 4.3% is public land. Roadside rights-of-way comprise around 60% of this public land within Iowa (Figure 1), representing a significant area where sustainable management techniques can improve water quality, reduce soil erosion, enhance aesthetics, and provide other public benefits.

Initial Considerations

Residents and county or city government employees may be among the first to be interested in starting a program that safely and strategically manages roadside vegetation using the principles of integrated roadside vegetation management.

People are most often interested in developing a roadside program because they want roadside management that is

Collect Information on the Current Need for the Program

Collecting information will help to make a strong case for an integrated roadside vegetation management (IRVM) program to a county board of supervisors or city council that may be skeptical of its necessity. These suggestions are a good starting point from which to consider how much information is necessary to collect for your county or city. 

County Vegetation Management Survey

Supporters need to gather the following information demonstrating the need for the IRVM program:

Obtain data from county herbicide-use records on the amount used, the cost, and the products used. Similarly, the county spray records typically provide information about who does the spraying, when it occurs, the technology used to spray, the miles covered each year, and the costs.

The County Vegetation Management Survey (Appendix 1a) can serve as a basis for evaluating a county’s roadside vegetation management program. Obtaining meaningful survey data may require interviews with members of the road maintenance crew or others directly involved. Though individual survey responses are subjective, the aggregate data will help identify and prioritize personnel and equipment needs. 

Where Are the Savings?

Counties and cities realize long-term savings by establishing native plant species that are better adapted and more competitive than non-native vegetation. Immediate savings are obtained by reducing or eliminating money spent on contractor services by

• spraying roadside weeds and conducting tree and brush removal with LRTF-purchased equipment; and
• installing and maintaining erosion control measures with county personnel.

A professional vegetation specialist on staff can provide additional savings by

Potential Objections to Starting a Program

Communicating the benefits of starting a program is important, but it’s also critical to be prepared to address the common objections given by those opposed. According to a 2016 survey of county board of supervisors and conservation board members (Stephenson et al., 2017), the greatest barriers to implementing IRVM practices are

Survey respondents said challenges to using native species include cost, adjacent landowners mowing the plantings, and acceptance internally or among contractors (Stephenson et al., 2017). A survey of engineers and roadside managers found similar barriers (Stephenson & Losch, 2016). Both reports provide useful background information about how county officials make decisions regarding roadside management. Of course, being familiar with local decision-makers’ values and perceptions of roadsides will allow citizen groups to be prepared for proposing this new initiative.

(Stephenson et al., 2017)

Proposing a Program to County or City Decision-Makers

Those wanting to start a roadside vegetation program, whether county or city employees or citizens, will need approval from the decision-makers to move forward: the county board of supervisors, city council, or city administrator/manager who controls the local budget, and the engineer, county conservation board director, board of supervisors, or city administrator/manager who will supervise the roadside manager. Program supporters will typically present the need for a roadside vegetation program at a board of supervisors or city council meeting.

Citizens who want less roadside spraying and more native vegetation often lead the effort to change their county or city’s roadside management practices. This may start with one person or a small group who recruits other citizens to join the cause. Once the group has formed, it can lay out its goals over the course of a few meetings.

The roadside program manager at the Iowa Roadside Management Office is available to answer questions and provide resources to help inform people about roadside programs. For example, the paper “Roadside Weeds, Brush, and Erosion: How Your County or City Can Manage Them to Create Safe, Healthy Roadsides and Roads” details the benefits gained from having a roadside vegetation program. Brochures about roadside programs and roadside vegetation are also available.

When the citizen group is ready, it should ask for time with the county board of supervisors to propose its vision and goals for the roadside vegetation program and request a formal IRVM committee. Unless the board can provide a large block of time during a regularly scheduled meeting, a special meeting specifically to discuss the proposal will allow for better discussion. The majority of the citizen group should be present at the meeting. 

Strategically choose the person or people to present about the proposed program based on who local decision-makers would trust the most. In some cases, it should be the county or city employee who would be responsible for developing the program and supervising the roadside manager. In other situations, decision-makers would also want to hear from one or more of the following people: the roadside manager, engineer, or conservation board director from a nearby county with a roadside program; a federal Natural Resources Conservation Service (NRCS) employee; a Soil and Water Conservation District commissioner; the chair of the citizen group; someone representing farming interests; a weed control professional; the statewide LRTF coordinator; or the roadside program manager at the Iowa Roadside Management Office. The goal is to fortify the effort with respected individuals who can address the board of supervisors with candor and knowledge.

No matter who presents, it is crucial to demonstrate local support with a high turnout of residents (ideally including some with political influence) who support the effort. 

The desired outcome for this initial meeting should be for the board of supervisors to appoint a formal IRVM committee to examine the county’s current roadside management practices and determine what is best for the county. Recommended IRVM committee membership includes one or more county supervisors, the county engineer, the road superintendent/foreman, the weed commissioner, a member of the county conservation board, and key members of the original citizen group.

Residents can also write letters to the editor of the local newspaper and email or call their local officials to convey their support for the program.

The simplest approach to developing an IRVM program is to think through the following details with your staff, community members, and stakeholders. 

Name of the Program

Example roadside program names:

Goals and Objectives

Goals are broad, long-term outcomes while objectives are short-term, measurable actions taken to achieve goals.

Examples of roadside program goals from IRVM plans are listed below. Some programs categorize these as short-term goals (e.g., 0–5 years), medium-term goals (e.g., 5–10 years), and long-term goals (e.g., 10–20 years). 

• Recognize and stop the spread of newly introduced invasive plant species in roadsides countywide before they become a problem.
• Minimize the use of herbicides and other chemicals to manage or eliminate undesirable plants. This includes the incorporation of prescribed burning, spot-spraying, and strategic use of herbicides, pesticides, mowing, and tree removal.
• Reduce erosion on county road construction projects by seeding and providing adequate erosion control. Use a long-term integrated management program that promotes desirable, self-sustaining plant communities. Whenever practicable, native plant communities are incorporated with roadside vegetation plantings.
• Enhance the scenic qualities of roadsides and their capacity as habitats for wildlife.
• Cultivate a communications strategy to build community support for the roadside management program.
• Develop a neighborly policy for dealing with right-of-way encroachment issues.
• Preserve and manage remnant prairie plant communities in the right-of-way through monitoring, prescribed fire, and brush removal.

Here are some examples of specific measurable roadside program objectives from the Dallas County IRVM plan:

To get ideas for other goals and objectives that would be appropriate for your county or city, see a sampling of approved IRVM plans. All of the plans include goals and some plans also have objectives. 

IRVM Plan

Counties and cities that want to apply for Living Roadway Trust Fund (LRTF) grants and request free native seed will need to submit to the LRTF an IRVM plan that is signed by the appropriate county or city officials. To formulate the plan, counties and cities will use one of two plan outlines: the IRVM Plan Outline for Counties, State Agencies and Cities over 10,000 in Population form or the IRVM Plan for Cities Under 10,000 Population form. These forms and approved plans are on the LRTF website.  

For most parts of the plan outline, roadside managers and other staff will be able to incorporate information already gathered and created during the new program's planning and implementation. The plan outline may be more or less extensive than the county or city’s internal program documentation. The LRTF coordinator is available for any questions that arise as you work on your plan.

Email the final plan to the LRTF coordinator for approval. Both IRVM plans and LRTF grant applications must be submitted by June 1. Once approved, plans should be updated and submitted for review by the LRTF coordinator every five years.

IRVM plans developed prior to 2015, when the LRTF implemented the latest plan requirements, are considered inactive. Counties or cities who do not have plans that meet the latest requirements are ineligible to apply for LRTF grants or request native seed.

Staffing and the Percentage of Time Each Staff Member Will Dedicate to the Program

Identify what staff member will implement the plan. County or city officials will sometimes have someone who is already on staff implement the plan. More often, counties will create a new roadside vegetation manager position. 

Ideally, the roadside manager will have wide-ranging knowledge and skills. The best candidates will have a strong background operating heavy equipment such as tractors, mowers, chainsaws, pickup trucks, trailers, skid loaders, tree planters, prescribed fire equipment, hand tools, seeders, and chemical spray equipment. They will also have good communication skills. Experience working with natural resources, vegetation, or both is an important bonus. Candidates must like a challenge and be willing to learn as they go. The county or city may hire the roadside manager before developing the IRVM plan and conducting the roadside vegetation inventory so the roadside manager can be involved in developing the plan. Conversely, the department hiring the roadside manager may prefer to write the plan first to articulate their vision for the program and develop local support for hiring a roadside manager to implement the plan. A generic position description (Appendix 1b) can be customized to fit your county’s situation.

Most roadside managers are responsible for at least 2,500 acres of roadside vegetation. They will be able to get more done if they have the assistance of a permanent or temporary technician and summer help. With proper funding, a roadside program has a sufficient workload to employ

Results from the latest roadside manager salary survey can help when budgeting for staff salaries. Potential funding sources in the county budget for roadside positions include the rural basic fund, secondary road fund, road clearing appropriation, and county conservation board budget. See an example of a roadside manager job description in the appendix.

The Full-Time Roadside Manager

The best way to achieve common roadside program goals is to hire a full-time roadside manager. As the person overseeing all roadside vegetation management duties, the roadside manager is focused and motivated to

• control weed and brush in a timely, effective manner;
• save money by conducting more in-house operations;
• stay current with the latest products and technologies;
• establish and maintain healthy stands of native vegetation;
• install and maintain erosion control measures; and
• submit LRTF applications to bring in additional resources that address county needs.

The roadside manager takes ownership of managing the county’s roadsides with pride and accountability. When one person coordinates every aspect of the program, the result is better roadsides. Although cities may not have the resources to hire a full-time roadside manager, they need to designate in their integrated roadside vegetation management (IRVM) plans who will lead the effort to manage roadsides using the IRVM principles.

A Less Expensive Way to Get Started

A few Iowa counties have planted a lot of native vegetation in roadsides without a roadside manager.  These counties do not have the same level of vegetation management as those with roadside managers, but they do have access to the LRTF. The following are examples of how this can be accomplished:

Hopefully, these and other similar nascent efforts by counties attempting to establish the use of IRVM principles act as catalysts to eventually hire full-time roadside managers. Maintaining healthy roadsides with native vegetation takes a sustained, focused effort. A county board of supervisors supporting the implementation of IRVM principles is necessary but not sufficient to make it happen—having an employee in a critical position who wants the program to succeed is crucial.

Steering Committee: Community Partners Who Can Help You With Referrals, Advertising, Implementation, and More

An IRVM steering committee (also known as an advisory committee) meets regularly to stay updated on the roadside programs’ activities and challenges and provides guidance. The committee can also can help spread the word within the community about the benefits of having a program and provide political support as needed. 

A steering committee may be formed at any time but most often evolves from the committee formed during the initial effort to establish a program or is formed when a roadside manager is hired. A committee typically meets 2–4 times a year and consists of 5–10 members representing the private and public sectors. The committee may be comprised of some of the following members:

The county engineer, conservation board director, or initial IRVM committee members may recommend people to appoint but the county board of supervisors has the authority to appoint members. Committee members often serve three-year staggered terms, which can initially be structured as follows:

• 3 members—1-year term
• 3 members—2-year term
• 4 members—3-year term

Once all of the 1-year terms are up, three people would be appointed for 3-year terms and once all of the 2-year terms are up, three more people would be appointed for 3-year terms.

The committee elects a chairpersons and secretary and meetings are subject to Chapters 21 and 22 of the Iowa Code concerning open meetings and public records.

Program Organization/Location

When deciding within which department to locate a county roadside program and who should supervise the roadside manager, keep in mind that greater independence allows for better planning and timely operations. Sometimes, a department may need to be restructured or reorganized to give roadside management personnel the autonomy to meet objectives. County programs can operate successfully within the engineer’s office, the county conservation board, or as an independent department. All three have advantages.

Generating Support for the Program

Members of a steering committee can generate goodwill for the program by communicating within their networks. Regular communication between the roadside manager and the committee members is important so members know about the roadside manager’s projects and what information to relay.

Working on projects that visibly show progress in a relatively short amount of time, such as brush control or seedings with signage, can help garner support for a new program. The appropriate level and type of publicity for a new program can vary depending on the county or city’s goals and progress on specific projects.

Chapter 3: Communication includes many ideas for developing and maintaining both internal and public support for a roadside program. 

How the Program Will Be Evaluated

Completing an IRVM plan and a county vegetation management survey can identify goals and objectives that serve as the basis for evaluating the program. Examples of ways counties have evaluated aspects of program success include:

Budget

These expenses should be considered when anticipating the cost of a program:

• full-time roadside manager salary and overtime pay
• full-time technician salary and overtime pay
• temporary assistants’ salaries and overtime pay
• contract labor
• FICA – county or city contribution
• Iowa Public Employees Retirement System (IPERS) city or county employer contribution
• employee health, life, dental, and long-term disability insurance
• herbicides
• stationery and other printing costs
• minor equipment and hand tools
• staff education and training
• operations and construction equipment
• fertilizer and seed

In the end, weed and brush control objectives are balanced against environmental concerns and limited county or city resources. With that in mind, determine an appropriate allocation of resources. Also, determine how much might be saved with better organization and efficiency.

The following steps need to be taken during implementation, which is the period right before the actual date that the integrated roadside vegetation management (IRVM) program officially begins and the months that follow.

Memoranda of Understanding 

Partner organizations must sign any necessary memoranda of understanding.

Passing a County/City Resolution

The county board of supervisors or city council will need to pass a resolution establishing the program. Resolutions may also need to be passed or adopted regarding sections of Iowa code that pertain to IRVM programs, such as 314.22, and to accept LRTF grants. Work with other county or city staff to determine what resolutions are required.

Passing a Budget

Some counties and cities develop and submit the budget for the roadside program to be passed by the supervisors or council separate from other expenses, while others absorb the expenses in another department’s budget. In either case, it will need to be approved by the relevant county or city governing body.

Hire the Roadside Manager and Train Staff

Provide the Tallgrass Prairie Center roadside program manager with the mailing address, email address, and phone number of the roadside manager leading the implementation of the IRVM program. The TPC roadside program manager will then send the roadside manager the following information:

• ‌The link to the online IRVM Technical Manual, with instructions on how to print sections should the roadside manager prefer a paper copy.
• Dates and locations for the next winter Association for Integrated Roadside Management (AFIRM) meeting, Roadside Conference, and Roadside Vegetation Programs 101 webinar.
• Information on the different responsibilities that the LRTF coordinator and TPC roadside program manager have so the roadside manager knows who to go to with questions.
• An inquiry to determine which field guides and brochures the roadside manager has, and providing any additional field guides or brochures that could be helpful.
• A request for a 3–5 sentence biography and photo to introduce the new roadside manager via the Iowa Roadside Management social media accounts and the Roader’s Digest email update.
• Information on how to reach out to nearby roadside managers who are willing to provide job shadowing by new roadside managers.

The TPC roadside program manager will then connect the roadside manager to the Iowa Roadside Management network by

• adding the new roadside manager’s contact information to the listing on the TPC website and internal email list consisting only of roadside manager email addresses; and
• adding the new roadside manager to the roadside management Google Group/email list and Roader’s Digest list, each of which is for those interested in roadside vegetation management.

Annual Operations

A list of annual tasks, duties, and projects can help the roadside manager understand their responsibilities throughout the year. Here is an example of a list of annual operations that appears in some IRVM plans. Some plans have a more detailed list that is organized by month.

Job Shadowing a Neighboring Roadside Manager

After the roadside manager has begun working, the Tallgrass Prairie Center (TPC) roadside program manager will give the person an opportunity to job shadow an experienced roadside manager from a nearby county who is willing to help new roadside managers. This allows the new roadside manager to develop an early peer relationship and learn how another county approaches roadside management.

Chemical Safety/Handling

Controlled pesticide application is a useful part of the IRVM toolkit. Pesticide use in roadside rights-of-way is considered public pesticide application, which requires a state Commercial Pesticide Application license. To become certified, the roadside manager must pass a 50-question, closed-book exam over the Core Manual - Iowa Commercial Pesticide Applicator Manual; pass a 35-question exam specific to right-of-way pesticide application; and pay a $15 fee for public applicators. Check here for Applicator Licensing and Certification testing dates from the Iowa Department of Agriculture and Land Stewardship.

Commercial Driver’s License

The Iowa DOT requires operators of vehicles that weigh 26,001 or more pounds to obtain a commercial driver’s license (CDL). Large pickups with trailers with a drill or spray equipment can top this weight. To obtain a CDL, applicants must complete applicable entry-level driver training from a registered training provider. Training providers charge an average of $4,000. For more information, see the Federal Motor Carrier Safety Administration Training Provider Registry.

Chainsaw Safety

There are several options for in-person chainsaw safety training:

These are some useful online resources for chainsaw training:

Prescribed Burning

Controlled burns are a useful and cost-effective IRVM tool. Burning roadsides helps to control weeds, eliminate brush, and return nutrients to the soil. The Iowa Department of Natural Resources (DNR) Forestry website lists relevant courses in prescribed burning. To become certified (known as “Red Card” certification) to conduct controlled burns, one must complete a field day (part of the S-130 firefighter training course) and a series of online courses. Field day options are usually listed on the Iowa DNR website in early spring.

Plant Identification

Identifying native and non-native plants is a vital skill for roadside managers. While recognizing noxious weeds may seem more important, it is equally important to recognize where native prairie plants are. Many prairie remnants are found on the sides of roads and train tracks, which are traditionally undisturbed areas. Remnant prairies are especially well-adapted to their environment, which makes them valuable sources for native seed.

Plant identification resources exist for every learning style. Commonly used resources are listed below. 

Webinars

• Botany Beginners—Exploring Iowa’s Native Plants: This Tallgrass Prairie Center course includes six one-hour webinars teaching people the basics of plant identification using Newcomb’s Wildflower Guide as a resource, and three webinars produced in partnership with Practical Farmers of Iowa featuring hosts walking in the prairie pointing out common prairie plants.
• Botany Beginners—Grasses for the Masses: Seven one-hour webinars from the TPC about cool-season and warm-season grass identification.
• Botany Beginners—Managing Prairie Strips: A TPC course for those who manage prairie strips and other Conservation Reserve Program plantings within farmland.
• Golden Hills Resource Conservation and Development (RC&D): Plant identification webinar recordings, many of which are taught by botanist Dr. Tom Rosburg. Some of the webinars that might be especially useful to roadside managers include:
  • Invasive and Native Look-alike Plant Species in Iowa
  • Common Weeds & Invasive Species of Iowa
  • Cirsium (Thistle) Identification

Books and Guides

• 

  Newcomb’s Wildflower Guide: This is the textbook used for the Botany Beginners courses. This guide contains both native and non-native wildflowers, shrubs, and vines. Its breadth (1,375 species) and easy-to-use key make it a valuable resource.

• Wildflowers of the Tallgrass Prairie: This guide contains high-quality images of 78 species, most of which are wildflowers. It is particularly useful for information on prairie remnants and ethnobotany. The guide is arranged in order of flowering time. It doesn’t include a key and has fewer species than the other books mentioned. The guide’s creators also produced complementary field guides for the wetlands and forests of the upper Midwest. 
• Prairie Plants of the University of the Wisconsin–Madison Arboretum: This is the most detailed guide on the list. It includes horsetails, ferns, rushes, sedges, grasses, shrubs, vines, weeds, and wildflowers and features both flower and fruit photos. Because the guide is arranged by plant family and doesn’t have a key, it is recommended for audiences who are already familiar with botany.
• ‌Weeds of the Great Plains: This guide features weeds commonly found in Nebraska and neighboring states, including Iowa.
• Native Seed Production Manual: This TPC manual features basic information for native seed production of up to 100 species of the tallgrass prairie flora of the upper Midwest.
• The Prairie in Seed Identifying Seed-Bearing Prairie Plants in the Upper Midwest: This book includes plant identification, seed descriptions, seed harvesting and cleaning information, and more.
• The Tallgrass Prairie Center Guide to Seed and Seedling Identification in the Upper Midwest: This guide shows how to help identify and germinate 72 species of tallgrass wildflowers and grasses. 

Websites

Plant ID Apps

Because plant ID apps aren’t 100% accurate, it is important to learn the basics of plant identification techniques using the resources above. That said, reputable plant ID apps can be used to provide roadside managers with a starting point when identifying plants. The apps also contain other information about species such as location, prevalence, etc. It is also good to be aware of the reputable apps to inform citizens who ask about them. Here are two that have been well-reviewed by amateur botanists.

• Pl@ntNet Plant Identification
• iNaturalist

Conferences and Field Days

Conferences Attended by Roadside Managers

The conferences listed below offer opportunities to network with other roadside maintenance professionals and participate in continuing education. Most roadside managers attend the winter Association for Integrated Roadside Management (AFIRM) meeting and the Tallgrass Prairie Center Annual Roadside Conference. Those who are also weed commissioners attend the weed commissioners conference, also known as the Iowa Invasive Species Conference. All three conferences include a lot of information directly related to roadside vegetation management and counties and cities are encouraged to budget for roadside managers to attend. 

The other meetings listed are attended by fewer roadside managers, such as those who live near the meeting location. The TPC roadside program manager may be able to offer roadside managers a limited number of scholarships covering the registration fee. 

Winterfest—Iowa County Conservation System

Winter Meeting—Association for Integrated Roadside Management (AFIRM)

• Approximate date: A one-day meeting between late February to mid-March
• Presentation and discussion topics are of interest to roadside managers.

Invasive Species Conference—Iowa Weed Commissioners’ Association

Iowa Prairie Conference

North American Prairie Conference

Roadside Conference—Iowa Roadside Management

• 

  Approximate date: A three-day meeting in September or October.

• Includes an afternoon of field trips.
• Attended by roadside managers, Iowa Department of Transportation staff, and others interested in roadside management.
• Includes an exhibition area with vendors and other organizations.

Upper Midwest Invasive Species Conference

• Approximate date: A three-day meeting held every other year in mid-October to mid-November. 
• One of the most comprehensive and largest invasive species conferences in the United States.
• Attended by a wide variety of researchers, natural resource professionals, and government agency staff.
• Includes an exhibition area with vendors and other organizations.

Conferences With a Roadside Management Table

The Iowa Roadside Management Office at the Tallgrass Prairie Center has a table in the exhibition area at some of the events below to educate attendees about roadside vegetation management. The table may be staffed by the TPC roadside program manager or roadside managers, whose registration fees would be covered by the TPC. A small number of roadside managers may also attend some of these conferences on behalf of their county or city.

Statewide Supervisors Meeting

• Approximate date: A one-day meeting held in early February in Des Moines.
• Attended by members of county boards of supervisors.
• Includes an exhibition area with vendors and other organizations.

Iowa State Association of Counties Spring Conference

• Approximate date: Three-day conference held in March in Des Moines. 
• Attended by all types of county employees.
• Includes an exhibition area with vendors and other organizations.

Iowa Statewide Association of Counties Fall Conference

• Approximate date: Three-day conference held in August in Des Moines. 
• Attended by all types of county employees.
• Includes an exhibition area with vendors and other organizations.

Iowa County Conservation System Fall Conference

• Approximate date: Three-day conference held in mid-September at a location in Iowa.
• Attended by county conservation staff, especially conservation board directors and others in leadership positions.
• Includes an exhibition area with vendors and other organizations.

Iowa Streets and Roads Workshop and Conference

• Approximate date: One-day workshop and two-day conference held in September in Ames or Des Moines.
• Attended by secondary road and street maintenance supervisors and staff and others interested in road and street maintenance.
• Includes an exhibition area with vendors and other organizations.

County Engineers Conference

• Approximate date: Three-day conference held in mid-December in Des Moines.
• Attended by county engineers and other secondary road department staff.
• Includes an exhibition area with vendors and other organizations.

Field Days

Many conservation-oriented organizations and equipment dealers offer useful field days. The organizations listed below host virtual and in-person field events.

Practical Farmers of Iowa

• A series of free field days during the growing season on topics related to sustainable agriculture, including prairie seeding and burning.
• Attended by natural resource professionals and private landowners.

Prairie on Farms Program (Tallgrass Prairie Center)

• One or two field days (not held every year) on planting native vegetation in agricultural fields.
• Attended by farmers and natural resource professionals interested in prairie restoration. 

Hawkeye Cooperative Weed Management Area Invasive Species Field Day 

• An annual field day held in August at a location in eastern Iowa.
• Topics include managing invasive species and other land management topics. 
• Attended by natural resource professionals and private landowners.
• Includes an exhibition area with vendors and other organizations.

Iowa Learning Farms 

• A free webinar series on topics related to land management such as soil health, improved water quality, and pollinator conservation. 
• All webinars are archived on its website.

Email Lists and E-newsletters

Joining email lists and subscribing to email updates and e-newsletters is a good way to keep up with the latest news in roadside equipment, vegetation management, and roadside management in Iowa and beyond.

Roadside Management Email List

The TPC roadside program manager maintains a roadside management Google Group email list. Email the TPC roadside program manager to be added to the group. Group members can pose questions to the group to provide insight and search archives of previous questions. Members pose questions to the group to gain insight about others’ experiences with equipment, share job openings, and share time-dependent news that can’t wait for the monthly Roader’s Digest email update.

Roader’s Digest Email Update

The Roader’s Digest newsletter, deemed the “Newsletter of the Iowa Integrated Roadside Vegetation Management Program,” was established by the TPC roadside program as a quarterly paper newsletter from 1989 to 2009. In 2017 it was reinstated as a monthly email update. Subscribe and read previous email updates and archived issues.

Midwest Invasive Plant Network E-Newsletter

The MIPN e-newsletter contains invasive plant news from around the region. People can subscribe and read previous newsletters on the MIPN website.

Iowa Native Plant Society Discussion Group

The Iowa Native Plant Society maintains a discussion group available to anyone interested in native plants.

Professional Organizations

Belonging to one or more of the following organizations can be an avenue for making professional connections and keeping up with innovations in vegetation management:

Taking Advantage of the Living Roadway Trust Fund

Taking Advantage of the Living Roadway Trust Fund

Since 1990, counties have enjoyed support from the Iowa Department of Transportation’s Living Roadway Trust Fund (LRTF). Roadside managers submit applications each year to acquire resources for their program. The LRTF does not fund salaries, tractors, or standard pick-up trucks; some heavy-duty trucks dedicated to IRVM activities may be funded. While eligibility for this funding requires only that a county have an IRVM plan on file with the LRTF, a county’s level of commitment to IRVM is a factor when grants are awarded. Having a full-time roadside manager demonstrates a strong commitment. Applications are due June 1 each year.

Typical Equipment Needed for a Program

LRTF grants can be used to cover 80–100% of the cost of most of these items. See the latest LRTF Funding Guidelines or contact the LRTF coordinator to verify if LRTF funds can be used for a particular purchase. 

• heavy-dutypickup truck (¾ ton or large enough for a fire pumper unit)
• 60 horsepower tractor with dual rear axle
• flatbed truck for use as a herbicide spraying rig
  • Many counties are using flatbed truck mounted spray units with chemical injection, spray heads, and GPS. LRTF will fund up to 80% of the cost. 
  • Sprayers are not a high priority for LRTF, so the more of the cost the county or city can cover, the better its chances of approval. The total cost can easily be $25,000. 
• truck or trailer for hydroseeding
• broadcast seeder
• hydroseeder (minimum 800 gallons with mechanical agitation) 
• six-foot native seed drill
• cultipacker
• boom mower
• chainsaws
• brush chipper
• GPS
• utility vehicle
• fire rigs and safety equipment
• straw mulch blowers
• harrows and drags
• trailers
• silt fence equipment
• equipment shed
• storage room
• herbicide storage equipment
• brush mowers
• broadcast seeder

Roadside Vegetation Inventories  

The most effective roadside management starts with an accurate picture of the condition of roadsides in the county or city. A roadside vegetation inventory helps decision-makers set management priorities and provides baseline data for measuring program success.

Information collected in a roadside vegetation inventory includes herbaceous cover, tree and brush cover, weed concerns, bare areas, and areas with erosion and encroachment. The inventory development process typically involves a windshield survey, which means observing the roadside conditions while driving throughout the county or city. Windshield survey observations can be recorded every quarter mile or whatever interval is needed. Those conducting the inventory must be able to identify weeds, distinguish native prairie vegetation from non-native grasses, and recognize areas of erosion and encroachment. If more than one individual is conducting the inventory in separate vehicles, training must be provided to ensure accurate, uniform data collection.

LRTF funds can be used to hire someone to do the inventory. The roadside manager and county engineer make the plan for the inventory process and train the person who does the inventory so the collected data will be accurate and useful. Allow six to eight weeks to complete the inventory. It is ideal to conduct the inventory in late summer or fall since this is the easiest time to identify stands of native vegetation.

If paid for by LRTF grant funding, rules stipulate that roadside inventories must be recorded on GPS devices. The LRTF provides free software for collecting and recording roadside inventory information. The LRTF also funds the purchase of GPS units, mapping software, and laptop computers.

People who may be hired to conduct a roadside vegetation inventory include:

Identify Prairie Remnants

Every county in the state has a few roadsides containing small patches of native plants descended from the original prairie. These prairie remnants may possess just a few species or they may be quite diverse. Either way, they provide a glimpse into the past and are valued as sources of genetic material and models for future prairie restoration. They merit protection.

Look for prairie remnants in places like an old railroad right-of-way that parallels the highway or land that may have been too rocky or wet to till. A thorough survey of roadsides in your jurisdiction is the best way to document the location of remnants and prevent their destruction. Generally, do not try to enhance a remnant by inter-seeding with native seed unless that seed comes from remnants in the immediate vicinity. 

Native Seed From the Iowa Roadside Management Office

Since 1998, nearly all native seed planted in Iowa rights-of-way has been provided to counties and cities at no cost to them. The seed has been paid for with Federal Highway Administration (FHWA) grant funding secured by the Iowa Roadside Management Office at the Tallgrass Prairie Center. The FHWA program providing the grant funding has undergone several name changes over the years and is currently the Transportation Alternatives Set-Aside Program. These funds are approved annually. 

Prior to requesting free seed, counties and cities must file an approved IRVM plan with the LRTF and provide the labor and equipment to plant the seed. These native seed mixes have a value of $250–350 per acre and can only be used in road rights-of-way. For example, the seed cannot be used along trails that are outside of road rights-of-way.

Each September or October, the TPC roadside program manager emails eligible counties and cities to solicit seed requests for the subsequent year. Roadside managers will need to decide how many acres they would like to receive and provide maps showing where seed will be drilled or planted using heavy equipment that may cause rutting of the soil greater than 6 inches. The Iowa DOT archaeologist will review this information to ensure no Indigenous burial sites will be impacted. Maps do not need to be provided for sites that will be hydroseeded or broadcast seeded since these methods cause only shallow soil disturbance that will not affect burial mounds.

The seed is typically distributed over a two-day period in April, May, or June at the shed south of the Tallgrass Prairie Center. The seed must be planted by December 31 of the following year. The FHWA requires recipients to provide a seed report with maps every six months showing where the seed was planted.

A few counties have created their own seed production plots to supplement the seed they obtain from the Iowa Roadside Management Office. Counties also occasionally purchase seed from commercial sources to supplement what they receive from the Iowa Roadside Management Office.

Create Data Collection Tools and Processes Needed to Evaluate the Program

GIS mapping tools can be used to record data on roadside management activities such as brush cutting, spraying, and invasive species removal. 

County Board of Supervisors or City Council

Of all the relationships a roadside manager has, the relationship with the county board of supervisors (or city council for municipal roadside managers) is in many ways the most important. Supervisors approve integrated roadside management program budgets, support grant applications, oversee individual projects, and more. Building and maintaining a close, collaborative relationship with the board lays the groundwork for a successful roadside program and sets the roadside manager up for success.

Members of the county board of supervisors can better understand roadside management programs if the roadside manager provides quarterly reports at board of supervisors meetings and invites supervisors on regular shop visits and tours. Engaging supervisors in discussions aligned with their interests, such as spraying weeds and brush mulching, helps build good relationships.

For example, aggressively spraying noxious weeds during the peak months of June and July and communicating about that work to the supervisors via an email update is one way to gain positive attention. Demonstrating progress in problem areas by sharing pictures of spraying and quantifying the work in acres treated shows the value of the work of the roadside manager. Showcasing projects and showing the supervisors that the work of the roadside manager is just as integral as any other facet of county road maintenance also helps garner support.

County Roads Department

Internal communication and outreach help foster good relationships, collaboration, and goodwill, even with colleagues in departments roadside managers work closest with—county roads or city streets departments. A well-connected roads/streets team also makes for smoother workflows and decision-making processes. 

Keeping engineers and secondary roads superintendents updated about planned actions is key to maintaining alignment with road projects. Involving secondary roads employees in brush control activities that transition from manual to more effective methods establishes good rapport with the roads department.

Offering training sessions to secondary roads employees on invasive plants, herbicide safety, and environmental concerns is beneficial for both departments. 

Remember, because the roadside vegetation program staff consists of only 1–4 people, making connections with other staff is crucial. The benefits of being an integrated part of the county or city government are plentiful, and the consequences of allowing yourself to become siloed could put the program’s future at risk. Additional internal communication practices worth considering:

• Be responsive. Fieldwork is the lifeblood of your job, but being out of the office frequently does not mean you should be hard to reach. Schedule time at your desk so you can reply to emails and return phone calls within 24 hours.
• Share updates from roadside vegetation management with the staff member responsible for county or city internal communications. They may include what you share in internal email updates, printed newsletters, etc.
• Offer to provide content about your program’s work for bulletin boards or display cases in county or city facilities.
• Introduce yourself to the county or city director of communications (or equivalent title) and express your interest in keeping county or city staff informed about the program.

Volunteer for internal committees (e.g., social, hiring, strategic planning) to show your willingness to collaborate and make connections outside of the roads/streets team.

County Conservation

Leveraging collaboration between departments, such as the conservation board and public works staff, supports the transition toward an integrated approach in proposing ideas. Many of the tips for internal communication for the county roads department listed above can also apply to the county conservation department.

Reports About Iowa County Official Perspectives on Roadside Vegetation Management

In 2016 and 2017, the Tallgrass Prairie Center (TPC) roadside program manager conducted research funded by the Living Roadway Trust Fund (LRTF) with social scientists from the UNI Center for Social and Behavioral Research on perceptions of roadside vegetation management from roadside managers, county engineers, county conservation board directors, and chairs of the boards of supervisors. Personnel from all Iowa county officials were surveyed, regardless of if they had a roadside program or not.

The survey results provide a sense of what stakeholders you will be working closely with think about topics such as mowing, soil erosion, cost savings, and the influence of roadside managers on the county’s overall approach toward use of native vegetation. These insights can be helpful to draw on when considering what topics to prioritize and emphasize when communicating internally. It is still important to talk to the stakeholders in your county or city to find out where they stand, as their opinions may vary from the general sentiment gathered from the survey. However, the survey results do provide helpful background information that can inform your strategic communications approach. 

Survey questions for roadside managers and engineers primarily focused on how they manage roadside vegetation, such as:

Survey questions for chairs of the board of supervisors and county conservation board directors included the following:

Reports summarizing results from all of these surveys can be found on the Tallgrass Prairie Center's "Survey Reports" page.

Understanding and Responding to Landowner Concerns

Roadside managers enjoy a harmonious relationship with most landowners who live near roadsides they manage. However, some landowners will be critical of the integrated roadside vegetation management (IRVM) approach. Some fear an increase in weed encroachment from the roadside, while others object to the appearance of native vegetation in the roadside. They may contact the roadside manager to voice their complaints. It is important to ask clarifying questions to understand their concerns before responding. The following scenarios and suggested clarifying questions are based on roadside manager feedback during a presentation about communication at the 2023 Roadside Conference.

Scenario 1

A landowner who moved from a city setting to a rural setting is unsatisfied with the unclean appearance of roadside plants and brush. 

Suggested clarifying questions: 

• What brought you to the country from the city?
• Would you define “unclean look?” What specifically is unappealing to you about the roadside?
• What would you like to know about how the roadsides are managed?

This information can be used to tailor a response to address the landowner’s specific concerns:

• Talk about the vegetation, explain what species are there, and help them make a connection between specific plants and the need for them to grow in a more natural manner, which may change the person’s mind about how the roadsides look.
• Enhancing roadsides is an investment in Iowa’s native habitat and wildlife that also keeps our roadsides safe.

Scenario 2 

A landowner is concerned about roadside weeds encroaching on their property. 

Suggested clarifying questions: 

• Which weeds are causing you problems?
• What specific weed pressure issues do you have?
• What practices are you using to control weed pressure on your property? 

This information can be used to tailor a response to address the landowner’s specific concerns:

• I would like to come take a look at the problem, assess the area, and come up with a solution for both you and the county.
• Native long-lived plants in roadsides suppress the kinds of weeds that tend to cause problems in crop fields.
• Explain the source of the weeds, whether it is from a neighboring property or from the roadside. If it is from the roadside, explain how you will remedy the situation.

Preventing Mowing and Spraying of Plantings

Sometimes, even after you have spent years maintaining a planting or remnant, the adjacent landowner may mow or intentionally spray it with herbicides, violating Iowa Codes 317.11 and 317.13. If this happens routinely with the same landowner, you may want to pursue monetary redress with the county attorney. However, if you are proactive with your communication strategy, you may be able to avoid having to take such action. 

Some roadside managers have taken the preventative step of talking to landowners or placing doorknob hangers on their doors. In the form of a letter or brochure, roadside manager can explain why they are planting and maintaining native plants in the roadside, why the need for mowing and herbicide use is greatly reduced with such vegetation, and provide contact information. Subsequently, you could provide an annual one-page handout with text and photos updating landowners on progress made over the last year, any “by-the-numbers” facts (e.g., acres planted/maintained and cost-savings estimates), and any other news from the past year (e.g., new equipment purchase, new signage, grant funding secured). Make sure to include your name and a head-and-shoulders photo of yourself to make the communication more personal. 

Establishing relationships and maintaining them is crucial to preventing adjacent landowners from mowing and spraying in the roadsides. This can’t happen without communication that shows respect for landowners and an understanding of the legitimate stake they have in how the roadsides are managed. Human nature indicates the landowners will treat you with reciprocal respect and deference to your area of expertise. 

Programs, Partnerships, and Events

Public Meetings and Community Events

Attending community events and public meetings can be an effective way to engage with the community. Some roadside managers have a booth at the county fair, for example. Other events that may offer opportunities to set up an information booth include city festivals, Independence Day celebrations, harvest festivals, free outdoor concert series, farmers markets, and more.

In odd-numbered years, the Iowa Department of Natural Resources holds Resource Enhancement and Protection (REAP) regional assemblies around Iowa. These assemblies are public meetings where citizens can learn about REAP expenditures and provide feedback. Since 3% of REAP funding goes toward roadside vegetation management, roadside managers often attend the meetings in their regions to answer any questions about how those dollars are spent on managing local roadside vegetation. 

County board of supervisor meetings and city council meetings also provide opportunities to convey to the public what you do and why you do it. Citizens who are active in local government attend in person. Others may watch the meetings on local government television channels, and many meetings are streamed live and/or archived online. Local reporters also may be in attendance, providing an opportunity for additional media coverage. Maintaining a good relationship with supervisors and councilors as described above is a great way to get invited to meetings. But don’t hesitate to reach out to staff who set the agendas for these meetings if you have not presented recently. See Chapter 1: Steps to Start a Roadside Vegetation Program for more on being a part of these meetings in the early stages of implementing an IRVM program.

Organizing Volunteer Events for Residents

Volunteers familiar with the roadside program may be able to assist with community outreach through activities such as giving educational talks, writing letters to the editor supporting the roadside program, and taking attractive roadside photos. Organized events such as roadside trash cleanups could be a good activity for groups. Although coordinating with volunteers takes time, their involvement can generate support for the program and result in media coverage.

Presentations for Community Groups and Schools

In every community, there are organizations and entities looking to fill time at their meetings with presentations about what is happening in the community. Members of these groups tend to be very involved in the community and have positive relationships across all sectors of public life. They are great to have as allies. Groups that roadside managers have spoken at include local chapters of master gardeners, master conservationists, Sierra Club, Pheasants Forever, Rotary Club, and Kiwanis Club. The TPC roadside program manager has a PowerPoint template with information about the benefits of roadside programs that roadside managers can request and modify to suit their needs.

Roadside managers have also spoken to school classes and extracurricular groups. The TPC roadside program manager may have stickers available that are popular with schoolchildren. If your county has a TPC root banner, bring it with you and invite children to lay down next to the banner so they can be amazed by how their height compares. Other educational activities related to prairie roots that meet Iowa educational standards are provided on the “Educator Resources” page of the TPC website.

Press Releases

Press releases can be used to notify landowners and the public about upcoming work to maintain transparency. You can also notify local reporters in order to generate media coverage for instances such as hiring a new roadside manager, receiving grant funding, and re-approval of the county or city LRTF plan. Some roadside managers also annually issue a press release about Iowa’s law related to the restriction of citizen mowing of roadside vegetation (iowadot.gov/maintenance/row-harvesting-and-mowing) in April or early May. See an example press release in the Appendix.

County or city communications staff can help write and distribute press releases. If you are distributing them on your own, email them (in the body of the email) to any reporters who have covered your work in the past and any generic or press release email addresses at local newspapers and television stations.

Collaborating With Nonprofit Organizations

Assisting with events such as field days and prescribed prairie burns hosted by nonprofit organizations can lead to valuable partnerships and publicity. 

Providing Equipment Rentals

Some county roadside programs, especially those located within the conservation department, will rent equipment such as seed drills to the public to build goodwill with the community.

Adopt-a-Prairie Program

A few county roadside programs have partnered with landowners to reestablish prairie vegetation in the roadside bordering their property. Landowners can apply and, if approved, the roadside manager removes the existing vegetation and replaces it with native vegetation. There does not need to be a road regrading project associated with the reseeding. See an example application for participating in an adopt-a-prairie program from Scott County.

Outreach Materials and Signage 

Signage for Plantings

Installing signage lets the public know that a planting is intentional and can help to avoid the perception that native roadside vegetation is just a bunch of weeds. Use signage in plantings and high-quality areas to showcase native species. Some counties prefer to print their own signs that include the county logo. Iowa Prison Industries (iaprisonind.com) is commonly used to print signs for local governments. Signs can include language such as “Roadside Prairie” or “Native Vegetation—Do Not Mow or Spray.” Counties that have an adopt-a-prairie program for residents and want a large number of signs can check with the LRTF coordinator to see if they can apply for an LRTF grant to cover the cost. Counties can also obtain signs from the TPC roadside program manager, who uses LRTF funds to pay Iowa Prison Industries to print a limited number of signs each year. Check with the program manager to see what signs are available.

For landowners who want to know where they can get signs for their prairie plantings on private property, see suggestions from the TPC.

Frequently Asked Questions

As you communicate with various constituencies, they are likely to have questions, a good sign they are interested and engaged. To help you as you field questions, the TPC website includes a list of frequently asked questions and responses regarding roadside vegetation management. If you are asked questions frequently that you think would be helpful for others to know, let the TPC roadside program manager know.

Posters and Guidebooks

The Living Roadway Trust Fund has free eye-catching posters available such as the seven beautifully illustrated guides to prairie plants and animals in the “Jewels of the Prairie” poster set; the pollinator poster series; and a “Roadsides of Opportunities” poster. 

The LRTF also has free spiral-bound guidebooks on how to identify pollinators, seedlings, trees, and shrubs. These books are great to have available when tabling at community events. The TPC roadside program manager may also have some available.

Brochures 

Roadside Management Series

The TPC roadside program manager has brochures on roadside vegetation topics such as Iowa’s mowing law and landowner questions regarding roadsides. 

How to Restore Prairie

The TPC has a set of 10 brochures that provide detailed how-to technical information for topics such as collecting seed, designing seed mixes, site preparation, seeding, and maintaining plantings. The information is distilled from the TPC Guide to Prairie Restoration in the Upper Midwest.

Banners and Roots

Banners with life-size images of roots available for ordering from the TPC capture people’s attention by conveying the tremendous density and size of prairie root systems like those found in roadside vegetation. Approximately 14-feet long when unfurled, these portable and durable banners roll up for easy storage. Some counties or cities display them in the local nature center, library, or county courthouse.

Prairie Root Specimens

Prairie root specimens from the TPC that are up to ten-feet long are an especially effective physical tools for public outreach. Similar to the prairie root banners, counties may display prairie root specimens at the local nature center, library, or county courthouse. To cover the cost of growing the roots over three years, the TPC charges over $2,000 per root specimen plus shipping. 

Other Promotional Materials

Stickers 

The TPC roadside program manager may have stickers available that read “Roadsides for Wildlife” or have the Iowa Roadside Management logo.

Pull-up Banner

The TPC roadside program manager may have pull-up banners with roadside vegetation information that can be borrowed for tabling at local community events. They may be shipped or picked up at the TPC in Cedar Falls.

Wall Calendar

The TPC roadside program manager produces an annual wall calendar with a theme related to roadside vegetation management. Previous themes have included “Historic Roadsides,” “Celebrating Remnants,” and “Plant This Not That.” Wall calendars are mailed to roadside programs in the fall.

Lesson Plans

The following lesson plans are available on the Tallgrass Prairie Center website.

Iowa Roadside Curriculum Project

The Iowa Roadside Management Office collaborated with a team of Iowa educators to create nearly 30 educational activities that relate to roadside vegetation, with topics including changes in roadside vegetation over time, how we define what a weed is, and looking for roadside wetlands. 

Prairie Roots 

In collaboration with the Tallgrass Prairie Center, a team of Iowa educators created a set of prairie roots lesson plans that align with Iowa Core standards for upper-elementary and middle-school students. Roadside managers can share the lessons with local educators or teach them when visiting schools.

Social Media

Social media platforms like Facebook, Instagram, and others are great ways to engage with those who support your efforts and other users (through shares from your followers) alike. It is most common for roadside programs to occasionally help draft posts for larger umbrella social media accounts, such as the county conservation board, county road department, or the main county or city accounts. A few roadside programs also have their own social media accounts. It is best to post at least once a week to encourage engagement and garner reach. 

The TPC roadside program manager maintains Iowa Roadside Management Facebook, Instagram, and YouTube accounts. 

Recordkeeping and Cost Data

Good recordkeeping is an important part of effective communication because it facilitates transparency, builds trust, and helps to justify the roadside manager position. Accurate and up-to-date digital recordkeeping is a vital part of a roadside manager’s job and should be started immediately. Detailed, readily-accessible records provide an easy data supplement (including number of acres planted, volume of seed obtained through the Transportations Alternative Program, and the number of locations sprayed) when roadside managers report to county boards of supervisors or city councils. 

Documenting expenses and material use is particularly useful, as it can be used as proof of the money and labor-saving benefits of IRVM, particularly when it comes to reduction of mowing and spraying. It is advisable to keep separate records for herbicide applications, as roadside managers are required to document every time they spray. 

As mentioned earlier, records documenting locations of roadside plantings are especially useful. Many roadside managers have partnered with their county’s geographic information system (GIS) division to develop useful tools for this purpose.

Report About Public Perspectives on Roadside Vegetation

In 2016, Trees Forever received funding from Living Roadway Trust Fund to oversee research on how key stakeholders, legislators, and other citizens view LRTF’s mission. Reports summarized results related to target audiences, resonating messages, and ways to drive engagement and support. These findings may be useful as you conceptualize your communications plan.

More on Communication Strategies

For more information on internal and external communications strategies related to roadside vegetation management, see the National Academies of Sciences’ “Pollinator Habitat Conservation Along Roadways, Volume 10: Midwest” guide, "Chapter 11: Communication Support.” 

Use seed adapted to local climate and growing conditions

Yellow Tag Seed

Iowa source-identified seed, distinguished by the yellow tag that marks it, is highly recommended for roadside plantings. The Iowa Crop Improvement Association certifies that this seed originates from Iowa prairies, which means it is adapted to Iowa climate and soil. This seed is often collected from multiple sites within a region of the state, giving it a broad genetic base and potentially making it adapted to a wide range of growing conditions. Buying yellow-tag seed also reduces the risk of accidentally introducing new weeds to Iowa. Most of the seed provided through the Tallgrass Prairie Center is yellow-tag seed.

Sources of yellow tag species and related information can be found in the Iowa Crop Improvement Association’s Iowa Seed Directory. Additional native seed sources and information can be found on the Tallgrass Prairie Center’s Iowa Prairie Seed and Service Providers page.

Local Ecotype

Local ecotype seed originating from Iowa or nearby that is not yellow-tag certified is also appropriate for roadside plantings. Counties or cities can obtain this seed by requesting it from vendors. Some counties establish their own local ecotype prairie grass and wildflower production plots with seed collected from prairie remnants within their county or region. This seed needs to be cleaned and tested to know how much live seed (the percentage of a seed lot that is viable and able to germinate into a seedling) is actually being planted. 

Cultivars

Cultivars or cultivated seed varieties are generally not recommended. Cultivars are often derived from regions too far south and west of Iowa, making them adapted to a different climate and growing season. Most are only available in a limited variety of species, are developed for forage production, and can be too aggressive in diverse plantings. 

Learn to read them

Commercial seed labels contain information related to seed quality. Labels include some or all of the following:

The amount of weed seeds in a sample can vary widely. Some amounts may seem high but are not necessarily a cause for concern. 

Roadside Real Talk

Insights From Roadside Managers and Other Professionals

It does seem high to have, for example, 380 noxious weed seeds per pound of native seed. But I sometimes get seed lots with over 1,000 noxious weed seeds per pound. In my mind, it's negligible since the actual weed seeding rate ends up being very low, and they are not necessarily all live seeds. The noxious weeds that show up in these tests are almost invariably annual agricultural weeds, so they will probably be gone within 2–3 years. The weed seed bank (at least in post-agriculture settings) is many orders of magnitude higher than these small amounts. Weeds listed as noxious on the tag are not necessarily Iowa noxious weeds either, so depending on who you buy from, they might not even need to report it that way. In other words, you may be seeding these weeds anyway without knowing their identity (they would be listed as a whole in the weed seed percentage). For example, wild buckwheat is noxious in Minnesota but not in Iowa. It could be labeled as a weed to cover bases for interstate commerce. While I wouldn't reject a lot like this, it would be worth keeping an eye on the planting.
—Justin Meissen, Research and Restoration Program Manager, UNI Tallgrass Prairie Center, 2024

As previously mentioned, some counties maintain seed production plots to supplement the seed they receive through the Transportation Alternatives Set-Aside Program or purchase. To learn how to establish and harvest seed production plots, refer to the Tallgrass Prairie Center’s Native Seed Production Manual. After becoming familiar with the basics of growing and harvesting seed, it can be helpful to talk with county conservation employees and roadside managers who have plots about their experiences. You can find out who currently maintains plots by emailing the roadside management Google Group email list, talking to the roadside program manager at the Iowa Roadside Management Office, or networking at the annual roadside conference or winter Association for Integrated Roadside Management (AFIRM) meeting.

Keep Seed Cool and Dry

The viability of native seed deteriorates rapidly at high temperatures and in high humidity.

A general rule of thumb for seed storage: temperature (Fahrenheit) plus percentage relative humidity should not exceed 100. Additional seed storage considerations include:

• Most seed will last at least a year at 50°F and 50% relative humidity.
• For each 10°F increase in temperature, seed longevity is halved.
• For each 1% increase in moisture content of the seed (not relative humidity), longevity is halved.

Example: Seed stored at 70°F and 6% moisture content has only one-quarter of the lifespan of seed stored at 50°F and 6% moisture. Likewise, seed stored at 50°F and 8% moisture content has only one-quarter of the lifespan of seed stored at 50°F and 6% moisture.

Ideal seed storage specifications vary with individual species, but most can be stored in a temperature- and humidity-controlled environment for at least a year without significant loss of viability. Some IRVM programs have a dedicated seed storage facility. These insulated rooms and small buildings are rodent-proof, air-conditioned, and sometimes have industrial dehumidifiers. In the absence of a dedicated seed storage facility, seed should be stored in the coolest place possible. Air circulation can improve conditions if it is impossible to control temperature and humidity. Most seeds can tolerate short periods of storage in temperatures over 100°F, but long-term exposure to such heat can destroy embryos. 

No reliable scientific guidelines support increasing seeding rates to account for lower seed viability when stored in suboptimal temperature and humidity conditions. Instead, the safest bet is to find funding for a proper seed storage facility to ensure seed viability.

Commercially produced seed is properly dried before being bagged. For counties and cities growing their own seed and bagging it, seed storage bags should be made of breathable materials such as cloth or woven nylon. Well-dried seed (8–14% moisture content, depending on the species) can be bagged and stored in garbage cans, larger plastic bags, or other sealed containers without suffering damage from fungus or freezing. Seed should be monitored for moisture buildup. Additional information on seed quality, processing, and storage can be found in the Tallgrass Prairie Center’s Native Seed Production Manual.

Roadside Real Talk

Insights from Roadside Managers and Other Professionals

We’ve noticed Liatris grows very poorly unless it’s dormant seeded shortly after harvest. Perhaps it loses viability or vigor when stored over winter, or maybe it needs to be stored at a higher humidity than most seed. 
—Jim Uthe and James Devig, Dallas County, 2024

With a little increase in rate per acre, I think year-old seed can be used with no problem. We use older seed (2–3 years) at whatever rate it takes to use it up over the course of the season. I add a reduced rate of new seed to cover any loss of germination. 
—Linn Reece, Hardin County, 2010

Take advantage of prairie diversity

Native seed mixes for roadsides must include species adapted to various growing conditions, from wet to mesic to dry. In order for the native plants to outcompete weeds, mixes should also include species that occupy different ecological niches, grass and broadleaf species, warm-season and cool-season species, plants that are tall enough that they produce shade that prevents weeds from growing, and small plants to fill in underneath.

When planting in narrow ditches, such as those found within a right-of-way that is 66 feet wide, it is most efficient to design one seed mix that includes species for a wide range of site conditions—from the gravelly, well-drained soils at the top of the slope, to the heavy, saturated soils at the bottom of the ditch. The same mix can be applied over the entire area and left to sort itself out. Wider rights-of-way may have larger wet or dry areas to justify designing and planting a seed mix specific to those spots.

To achieve a well-rounded seed mix with all the benefits of native vegetation, include species from each functional group described below.

Quick-Establishing

These native species establish faster than others, provide early erosion control, and show demonstrable progress to community members while slower species establish.

Warm-Season Grasses

Roadside plantings rely heavily on these prominent members of the native plant community. These grasses continue to grow through the hot summer months. They provide long-term erosion control and good fall color.

Cool-Season Species

Roadside plantings are strengthened by a species component that greens up early in the spring. These plants provide late winter/early spring erosion control and occupy the niche sought by non-native, cool-season competitors like smooth brome.

Legumes

The prairie flora includes many legumes that thrive in roadside plantings. They fix nitrogen, or in other words, with the help of bacteria that grow on their roots, they convert atmospheric nitrogen gas that plants cannot use into a usable form of nitrogen, such as nitrate, that plants can use to grow. When legumes die and decompose, the nitrogen in their root and leaf tissue is released into the soil. By making nitrogen more readily available in the soil to various plant species, legumes improve growing conditions for many different types of plants.

Showy and Easy

These crowd pleasers establish readily, are relatively inexpensive, and create masses of color noticeable to residents swiftly driving by.

Showy

The following species cost a little more or are harder to establish but still add important color and habitat.

Early Bloomers

Extending a planting’s blooming season into the fall is relatively easy, but spring color is harder to come by. The following plants provide the earliest color visible from the road.

Wet Species

Upland species that are adapted to dry (xeric) or moderate soil moisture (mesic) conditions dominate roadside seeding mixes to reflect the growing conditions along the upper and middle part of the ditch. Species adapted to wet areas are needed for moist ditch bottoms.

For additional assistance with designing seed mixes, see the Tallgrass Prairie Center’s Designing Seed Mixes technical guide and seed calculator.

A Note About Tall Grasses and Non-Native Perennials

For visibility and safety, tall grasses—such as big bluestem and Indiangrass—should not be planted at intersections or driveways. However, omitting these grasses from other roadside areas will limit a planting’s adaptability. Big bluestem and Indiangrass are versatile and adapted to conditions from medium-dry to medium-wet. Short native grasses, on the other hand, are generally adapted only to dry sites.

Non-native perennials—such as tall fescue, perennial ryegrass, crown vetch, and birdsfoot trefoil—are very competitive and will persist to the point of adversely affecting the survival of native seedlings. These species should not be used in permanent or temporary mixes for native plantings.

Seed Mixes for Shoulders

Native species are not to be planted on the shoulder. Seed mixes that withstand repeated mowing and are well-suited to shoulder conditions include:

• 50% Kentucky bluegrass, 31% fescue, and 50% perennial ryegrass
• 45% Kentucky bluegrass, 31% fescue, 45% perennial ryegrass, 6% medium red clover, and 4% alsike clover
• 35% fawn tall fescue, 35% perennial rye, 20% Timothy, and 10% alfalfa or hairy vetch

Roadside Real Talk

Insights from Roadside Managers and Other Professionals

Keep in mind, in most situations, we’re not recreating a diverse prairie. We’re stabilizing the roadside with native plants.

We use local ecotype hand-harvested forbs and combined seed from our native seed nurseries to add diversity to our roadside seed mixes. 

Try to tailor your mix so the right-of-way has color all year long.

—Joe Kooiker, Story County, 2024

Aspect and shading sometimes need to be taken into account, especially on small plantings or problem areas. In shaded areas, we use savanna species in the mix. If there’s a lot of shade, we may plant a non-native, cool-season mix. 

Depending on soil type, we may use up to one-and-a-half times the rate of native seed to help speed establishment and stabilization.

—Jim Uthe and James Devig, Dallas County, 2024

Put Down Enough Good Seed to Get Timely Vegetative Cover and Ensure Planting Success

Steeper slopes require heavier seeding rates. To achieve adequate erosion control, increasing the amount of grass in the mix is more cost-efficient than increasing the forbs. As a result, roadside plantings tend to have a higher grass-to-forb ratio than other prairie restorations. No matter how much native grass seed is included, at least 25% of the mix’s weight should be a forb component to achieve adequate diversity and long-term stability. For even more diversity that will provide more visual appeal to drivers and attract pollinators, increase the proportion of forbs to 50%. Some counties and cities—especially those with their own forb seed plots—may exceed 50% forb content for intersections and other highly visible plantings.

Seeding rates are calculated in one of two ways:

• seeds per square foot (seeds/sq. ft.)
• lbs. per acre (lbs./acre)

Though frequently used, lbs./acre is not a precise way of measuring the number of seeds planted since seed weights vary greatly between species. For example, one ounce of compass plant contains 660 seeds, while one ounce of black-eyed Susan contains 92,000 seeds. Under actual working conditions, even the best attempts at measuring seed quantities in the field will be imprecise. However, for the most accurate calculation of seeding rates, use seeds/sq. ft.

Seeding rates for roadside mixes are determined by the slope of the roadside where the seeds will be planted and, to a lesser degree, the seeding method that will be used (i.e., drill seeding, broadcast seeding, or hydroseeding). Cost can also be a factor. The following chart provides general guidelines for how many seeds should be planted.

Minimum Recommended Seeding Rates

These rates apply to drill seeding, broadcast seeding, and two-pass hydroseeding. When hydroseeding with seed mixed in the slurry (one-pass method), increase rates by 15–30% to compensate for seeds that are stuck in the mulch, preventing the seed-to-soil contact needed for the soil to germinate.

The Sample Native Seed Mixes appendix contains a sample diversity mix and ditch cleanout mix with seeding rates. The seeding rates can be adjusted, depending on the slope of the roadside and the seeding method being used.

For additional assistance creating custom seed mixes, visit the Tallgrass Prairie Center’s Iowa Prairie Seed Calculator. This web resource allows users to enter variables such as soil moisture, seeding method, planting season, etc., and get a custom-recommended native prairie seed mix with a cost estimate and a list of vendors who sell the seeds in the mix.

May and June are ideal for seeding, but road construction during these months limits opportunities. The following provides suggestions for protecting slopes and improving seeding success throughout the year.

January to Mid-March

Winter months occasionally present windows of opportunity for frost seeding if the soil temperature is around freezing (32°F), daytime temperatures are above 32°F, and nighttime temperatures are below 32°F. Frost seeding involves spreading seed over bare soil made friable (loose or porous) by a cycle of freezing and thawing. Results can be good, but opportunities for frost seeding can be brief, and adhering to the following tips can increase the chances for success:

• Be ready to jump on it when the conditions are right.
• Include oats as a cool-season nurse crop.
• Do not frost seed on areas covered with ice or snow.
  • Occasionally, native seed is sown on top of snow. Technically, this is not frost seeding but can be an effective winter seeding method for relatively level sites.
• Frost seeding on slopes is not recommended.

Late March Through April

If the ground is not frozen or too sloppy, this can be a good time for seeding. Warm-season grasses will not germinate until soil temperatures reach 60°F. Oats should be included as a cool-season nurse crop.

May and June

This time of year provides the best soil temperature and moisture conditions for germination and survival of warm-season species, including most prairie grasses and wildflowers.

July and August

Although every county can point to instances of successful plantings during these months, hot and dry summer conditions are generally less favorable for planting natives. Temporarily seeding a quick-growing stabilizing crop such as oats (see the “Cover Crops” section in this chapter) can be considered during these months, followed by permanent native seeding in the fall or the following spring.

If local circumstances dictate that natives must be seeded now, following these tips can increase the chances of success:

September and October

Native seed germinating this late in the season is unlikely to develop enough root reserves to overwinter (i.e., live through the winter). Yet some of these plantings succeed, perhaps because a lot of the seed does not germinate until spring. While more research is needed to know what contributes to successful planting during these months, the following tips are worth considering:

• Erodible sites must be stabilized with winter wheat.
• Increase the seeding rate by 25%.

November and December

Dormant seeding involves seeding when the ground is not yet frozen but cold enough that seed will not germinate until the warmer spring months. The majority of native seed will remain dormant over winter. It is considered a good option on level ground but is more complicated on erodible slopes. Cover crops seeded this late will not provide erosion control until spring. While some forb species do better when dormant seeded, some native grass seed planted at this time will deteriorate over winter. Some tips for dormant seeding:  

• Erodible sites must be stabilized with winter wheat.
• Increase the seeding rate by 25%.

Roadside Real Talk

Insights from Roadside Managers and Other Professionals

Timing is everything. Watch the weather, and don’t just seed a site to get it off the list.

—Joe Kooiker, Story County, 2024

Ideally, we begin dormant seeding in October or November once the 4-inch soil temperature reaches 50 degrees, but if erosion is a concern or there is an issue regarding a regulatory permit, we will seed earlier and may increase the seed rate some and hope for dormant seed.

—Jim Uthe and James Devig, Dallas County, 2024

I try not to seed in August, September, or early October. I prefer to wait until November, then drill into a cover crop and mow the following spring. If weather conditions deteriorate in November, I can still seed in the spring. However, there are many factors that can influence when seeding gets done, including size of project, time available, topography, etcetera. Small sites and those that are not conducive to drilling typically get seeded as soon as possible. I don’t intentionally wait to frost seed. I might consider it, but only on flat areas in perfect conditions.   

—Wes Gibbs, Jones County, 2024

Site preparation enhances seed-to-soil contact, helps ensure proper planting depth, and can even provide erosion control. Many roadsides that need to be seeded already have bare soil because vegetation was removed as part of the regrading work associated with a road project or because a ditch cleanout project removed silt that had run off from an adjacent field. Whether existing vegetation needs to be removed or not, additional preparation can increase planting establishment.

Before working on a site:

Seedbed Preparation for Drill Seeding

Seedbed Preparation for Hydroseeding

Heavily Compacted Soils

Roadside Real Talk

Insights from Roadside Managers and Other Professionals

Getting your seeds to grow is a priority. Try to get good seed-to-soil contact when possible.

—Joe Kooiker, Story County, 2024

For hydroseeding, we prefer the site to be rough and a little soft. We seed immediately after the construction equipment has left, with no additional seedbed preparation. The rough texture keeps the seed in place, and the softness allows for better root penetration. However, for drill seeding, firmness is the most important factor. It is easy for seed to get buried too deep in soft seedbeds, either during or post planting.

—Doug Sheeley, Dallas County, 2024

Cover crops help hold the soil in place and reduce erosion. They are recommended on slopes 3:1 (meaning a 3-foot horizontal run for every 1 foot of vertical rise) or steeper. Some roadside managers will only use cover crops on slopes they consider to be steep. However, they can also be used on more level ground to reduce the amount of weeds. Cover crops can outcompete weeds by taking up nitrogen and phosphorus from the soil, reducing the amounts that could otherwise fuel weed growth. Since cover crops are annual plants, they will be gone by the time native plants start to take off during the second growing season after initial planting.

There are two kinds of cover crops. Cover crops planted with the permanent native seed mix are called “nurse crops” or “companion crops.” Those planted by themselves outside of the optimal native seed planting season are called “temporary seedings” or “stabilizer crops.”

Oat (Avena sativa), annual ryegrass (Lolium multiflorum), and winter wheat (Triticum aestivum) are excellent cover crops because they are inexpensive, easy to establish, and not overly competitive.

Ryegrass

Many kinds of ryegrass are used as cover crops, including annual ryegrass, perennial ryegrass (Lolium perenne), and winter/cereal/grain ryegrass (all names for the same plant, Secale cereale). Perennial ryegrass is less aggressive than Secale cereale. Some roadside managers may include low rates of perennial ryegrass as a cover crop but use a shorter turf variety rather than a robust forage variety.

For native plantings, winter wheat is preferred over Secale cereale for cover crop purposes. Secale cereale is taller, more persistent, and can produce allelopathic compounds, meaning it could release biochemicals that inhibit the growth of wildflowers. Planting minimal amounts of ryegrass (5–10 lbs./acre) will reduce competition with natives. Annual ryegrass may germinate better with dormant or frost seeding. 

Recommended Nurse/Companion Crops (Planted With the Native Seed)—per Acre

Recommended Temporary Seedings/Stabilizer Crops (Native Seed to Follow in the Spring or Fall)—per Acre

Summer

• 1 bushel oats plus 10 lb. annual rye and one of the following warm-season species:

  • 5 lb. piper sudangrass
  • 10 lb. millet (Japanese or Pear varieties)
  • 30 lb. sorghum (grain or forage)

Use moderate rates when seeding piper sudangrass, pearl millet, or sorghum. One good rainfall can cause mass germination. Piper sudangrass may cause concern among landowners because it is sometimes confused with the weed “shattercane.”

Fall

• 3–5 lbs. of annual ryegrass
• 45 lbs. of winter ryegrass
• 60 lbs. of winter wheat

Preventing Competition Between Cover Crops and Native Plants

Mowing plantings one or two times in the summer to a height of 20–24 inches will keep the cover crops and weeds from shading out the native plants.

Roadside Real Talk

Insights from Roadside Managers and Other Professionals

Cover crops are as much for public perception as they are for erosion control. Having your plantings turn green in a timely fashion is essential for a program’s success.

—Joe Kooiker, Story County, 2024

We use a bushel per acre of winter wheat as a nurse crop when dormant seeding with a hydroseeder. In the spring, when hydroseeding, we use a bushel of oats if the soil prep and soil moisture forecast are appropriate. We may continue to use oats through summer in good soil that’s adequately prepped and if moisture is in the forecast. We will blend in annual rye and/or even pearl millet or may substitute the oats for these species as the soil conditions and forecast become less favorable.

In addition to increasing our native seeding rate on very steep slopes, we also increase our cover crop rate. We essentially do this by applying more material out of the hydroseeder as the concern for erosion increases.

In typical Iowa soils, fertilizer and plant growth hormones aren’t needed. However, we’ve used various growth stimulants along with starter fertilizers and various other amendments on steep slopes with poor soil and have had very good results. It’s cheaper to quickly establish a cover crop than to spend the time and resources repairing or redoing a project. It’s also good PR with the engineering staff and public to see a quick green-up. Again, we only use this practice on areas with very poor soil with a lot of erosion potential or to protect a high-dollar project.

—Jim Uthe and James Devig, Dallas County, 2024

The majority of our regraded slopes are steep. I regularly use 2.5 bushels of oats, 6 pounds of annual rye, and 3 pounds of Timothy [a cool-season grass] along with the permanent seed mix. This provides a better chance of stabilizing the slopes while the permanent seeding establishes, and I haven’t noticed any detrimental effect on the planting’s long-term success. 

—Linn Reece, Hardin County, 2011

The nurse crop can be added to the slurry in the second pass with good success. Wheat and oats are very difficult to keep in suspension in pure water, so it’s better to include them in the mulch in the second pass.

On large, contracted projects, we fertilize the cover crop to DOT specs; the flush of weeds has usually subsided by the time we plant natives in the fall or the following spring. We do not use fertilizer when hydroseeding. 

When broadcasting in light tillage, we use some, but sparingly. I wouldn't recommend fertilizer with natives, but it does help cover crops planted in nutrient-deficient soils. 

—Wes Gibbs, Jones County, 2024

I have used several different cover crops, from oats, winter rye, buckwheat, and perennial rye, to experimenting with sorghum grain and Sudan grass, and millets for summer ditch cleanouts and other projects. I will utilize these species because they are drought-tolerant and fast-growing. I plant oats at 30–40 pounds per acre, winter rye at 1 bushel per acre, and perennial rye at 10 pounds per acre. I keep the rye and oats thin to get some fast green on projects, but then the natives can out-compete them in the long run. I plant buckwheat at 10–20 pounds per acre on summer projects. I keep it on the lighter side with oats and perennial rye because they have a large leaf and can shade out natives until mowing a first-year seeding. I like buckwheat in my summer blend because it is fast-growing and drought-tolerant.

Most of these cover crops are broadcast-seeded. However, I have done some drilling and mixed it in with the hydroseeder as a method of seeding. I have seed success with all application methods.

Oats are a good cover crop to drill natives into because oats are fast-growing, short, and mature before the summer takes off. It is relatively cheap seed to purchase per bag and in large quantities. Oats also flow well in drills because of their large seed size, and they are easy to calibrate your drill to.

Here are my preferred cover crop seedings, mixes, and rates per species:

—Griffin Cabalka, Black Hawk County, 2024

Native seed can be ordered pre-mixed. However, if species are ordered individually, they must be mixed thoroughly. Seed can be mixed by mechanical mixers or by using the following tips:

There are three main seeding methods: drill seeding, broadcasting, and hydroseeding. Each method has advantages and disadvantages.

Drill Seeding

Seeding with a native grass drill is the preferred method on level roadsides. Drilling is a quick one-step process that effectively and rapidly establishes native grasses and is cheaper than hydroseeding.

Drilling should be avoided on slopes. At 3:1 or steeper, the drill will try to slide sideways, causing the disc openers to dig in and bury the seed. Projects with silt fences present another challenge, as maneuvering a tractor and drill around these fences is difficult.

Drill Seeding Tips

Hydroseeding and Hydromulching

Hydroseeding involves the spraying of a slurry comprised of water, seed, dye that is typically green, and optional fertilizer. It is ideal for bridge approaches, cleanouts, culverts, and wet or steep slopes. In most cases, the entire project can be hydroseeded from the shoulder. Hydromulching involves the same process with mulch added to the slurry. Other advantages to these approaches include:

• Hydromulching reduces soil erosion.
• Hydroseeding eliminates the possibility of seeding too deep.
• Hydromulch that is made colorful with the addition of a dye makes a positive impression on the public.

Filling the hydroseeder takes time, so drilling or broadcasting are usually quicker approaches for larger projects. Other hydroseeding and hydromulching disadvantages include:

• Mulch is expensive and can double the cost of a seeding project.
• The seeding rate is harder to control.
• Hydroseeding and hydromulching are strictly bare-ground applications.

Hydroseeding can be done using either a one-step process or a multi-step process. For the one-step process, the slurry is sprayed onto bare soil. When a one-step process is used, the seeding rate needs to be increased since the seeds are part of a mixture and may not have good soil-to-seed contact. As in other situations, the seeding rate should also be increased on particularly steep slopes. When seeding in the fall, when wildflowers germinate better, some roadside managers will increase the proportion of the seed mix that consists of wildflowers.

For the multi-step process, the seed is sprayed first, followed by mulch. Some roadside managers spray the cover crop first, then the seed, and finally, the mulch on top of the cover crop and seed mixture.

Regardless of the process used, following up with straw will help reduce erosion until the cover crop and native seed mixture gets established. Depending on the topography, it may not always be possible to get in and crimp the straw.

Hydroseeding and Hydromulching Tips

For more information on hydromulching, see “Chapter 6: Erosion Control.”

For more information on hydroseeding, see the Tallgrass Prairie Center’s “Hydroseeding Survey of IRVM Counties in Iowa.”

Broadcast Seeding

Broadcast seeding is a viable option with clean, non-fluffy, commercially available native seed. This debearded seed can be widely distributed when applied with broadcast seeding equipment. 

Broadcast Seeding Tips

Hand Seeding

Scattering seed by hand followed by light raking is very effective for smaller sites and prevents fine seed from being planted too deep.

Hand Seeding Tips

• To improve distribution, mix the seed with a carrier. Sand is best, but cat litter or oats can also be used.
• Mix the seed and carrier in a bucket and scatter it over the site by hand.
• Many species planted in wet prairies have fine seeds and should be hand-seeded.

Packing the Seed

Packing seed tightly to the soil ensures a more consistent flow of moisture from the soil to the seed, which results in better germination and seedling survival.

• Packing is most important after broadcast seeding but is always beneficial.
• A 4-foot cultipacker on a 3-point hitch system is very effective and will go places the tractor and drill cannot go, such as slopes that are especially steep.

Drones

Recently, drone seeding has emerged as another method for seeding cover crops and native seed. However, drone seeding can be pricey. Many Natural Resources Conservation Service (NRCS) offices maintain a list of drone seeding contractors for those interested in learning more. 

For roadside managers interested in using a drone for seeding, local agriculture co-ops may have one available to rent, or counties or cities can purchase one. Many resources, such as YouTube videos, explain how to apply native seed using a drone.

Roadside managers who want to operate a drone for seeding must also obtain a drone license. Contact the Federal Aviation Administration to learn more about the required license type.

Roadside Real Talk

Insights from Roadside Managers and Other Professionals

We lightly disc the seedbed before hydroseeding, if possible, cultipack after we seed, then apply mulch for a two-pass method. Hydroseeding is a great method of seeding, but not always necessarily the tool for the job.

—Joe Kooiker, Story County, 2024

When filling a hydroseeder from a creek, know your source. Don’t fill from an area with invasives, such as purple loosestrife. When hydroseeding, be sure to mix seed thoroughly in the water, both initially and periodically, during application. Our Finn hydroseeder can reverse the mechanical agitation, which is helpful.

There’s been some concern about high mulch rates affecting seed germination. I don’t think that’s an issue with large grass seeds, and even small seeds aren’t affected when dormant seeding with a high mulch rate since the mulch softens and breaks down over the winter. The seed can’t germinate if it’s washed away, so use enough mulch to get the job done right. 

When mixing seed, we mix 10 acres worth of the fluffy grass, such as sideoats grama, big bluestem, Indiangrass, little bluestem, Canada wild rye, and compassplant and put it in large plastic garbage cans. Then we mix 10 acres worth of the remaining forbs in a large rubber tote and put the two slick grass seeds, rough dropseed and switchgrass, in a third tote. Our fluffy grass rate is around 10 to 12 bulk pounds per acre, our forbs are usually around 3 to 4 pounds per acre, and our slick seed is around 2 pounds per acre. When hydroseeding, we bump these rates an extra 30 to 50 percent at times, depending upon site conditions and current climatic factors. We pretty much always seed with mulch, and we typically use 1,500 pounds of wood fiber mulch per acre. Our 3,300-gallon unit seeds about 0.9 acres pretty well with 1,350 pounds of mulch in it, or 3,600 gallons of material per acre. Some people I know put 1,500 pounds in a 3300-gallon seeder and seed a full acre, but we always seem to run a little short doing it that way. 

—Jim Uthe and James Devig, Dallas County, 2024

Filling near the site with a trash pump has drastically improved the efficiency of the process. We mounted the pump on the seeder, so we simply drop a fill line into the water and turn on the pump.

—Josh Brandt, Cerro Gordo County, 2010

We have better germination with lighter hydromulch rates of 400 to 500 pounds per acre.

—Dave Sedivec, Chickasaw County, 2010

Don’t trust your drill to meter your seed. Know your acreage and equally distribute the seed.

—Wes Gibbs, Jones County, 2024

When hydroseeding, you initially have to know how much area you are covering with a full load. With our Finn T-90, I cover a third of an acre per load. That may be more than is recommended for that size of a machine, but it means fewer loads per job and is quicker to finish. With our 22-foot wide ROWs on average, we travel 660 feet to make that one-third of an acre. With practice, you can become pretty accurate—arriving at 660 feet with an empty hydroseeder. If we use UNI’s recommended rates, then big bluestem at 1.5 pounds per acre, for example, uses 0.5 pounds per load. We weigh out the amount of each species needed for one-third of an acre and put it in one bag ahead of time. Then, we can just dump the bag in each load. This holds true for the nurse and temporary crops as well. 

—Linn Reece, Hardin County, 2011

Occasionally, landowners will contact the county or city to request a native planting in the roadsides adjacent to their properties. If the site is conducive to a successful native planting, some counties and cities accommodate these requests. Converting roadsides from non-native to native requires eliminating the existing vegetation, usually by application of glyphosate, a herbicide used to kill certain weeds and grasses. Cool-season grasses such as smooth bromegrass, fescue, and Kentucky bluegrass can be persistent and might require more than one application.

Conversion Tips

Establishment Mowing

During the first growing season, native seedlings remain small and can suffer losses due to competition with tall, thick weeds.

• Mow the planting three or four times during the first growing season.
• Do not wait until the weeds are too tall.
• The ideal mowing height is 8 inches to avoid mowing the vegetation so short that the stems are exposed, but as low as 4 inches would also work. 

Evaluating New Plantings

First-year native seedlings are small, making them hard to see and identify. As a result, people often worry that the plantings are a failure. These tips can lead to a more accurate evaluation of the progress of native plantings:

The following types of soil erosion are of greatest concern for roadside managers.

Occurring on Slopes

Splash Erosion

Raindrops dislodge exposed soil particles, causing erosion. These particles settle in soil pores and, when dry, form a crust, reducing infiltration during subsequent rains.

Sheet Erosion

This type of erosion occurs in heavier rains on uniformly smooth soil surfaces. The raindrops carry soil particles away in a shallow sheet of water.  

Rill Erosion 

Slight differences in soil surface elevation cause runoff to concentrate and form a pattern of cuts or rills. This type of erosion is more likely to occur than sheet erosion since slopes are rarely uniformly smooth.

Occurring in Concentrated Flow Areas

Channel Erosion 

This type of erosion is due to the force of flowing water. Many, if not all, roadsides are conduits for this kind of concentrated stress on the soil.

Erosion control objectives should be considered in the planning stage of every roadside vegetation project. Many factors affect a site’s erosion potential. Some of those same factors also affect how quickly vegetation will establish and provide stabilization. The following interconnected factors should be analyzed to determine what, if any, erosion control practices are necessary:

• time of year (How long will the soil be exposed?)
• soil type and fertility
• slope length, grade, and aspect
• potential for off-site surface water to flow into the project area
• type of seed mix (e.g., warm-season seed establishes slower than cool-season seed)
• weather forecast
• the consequences of failure, which may include weakening the stability of the road or infrastructure such as culverts
• the presence of sensitive areas (e.g., wetlands, sensitive waterways and critical habitats for threatened and endangered species that may be negatively affected by an influx of soil and pollutants associated with erosion).

Erosion Control and IRVM

Some IRVM programs will be more involved in erosion control than others. Sediment control and long-term erosion control may be the responsibility of other county or city departments or a hired contractor.

However, at a minimum, all IRVM programs are responsible for short-term soil protection through proper site preparation and use of nurse crops, stabilizer crops, and mulches.

General short- and long-term erosion control techniques are outlined below. At the end of this chapter, there is a list of useful erosion control industry websites with up-to-date technical specifications and guidelines. Take advantage of these resources and other educational opportunities to stay well-informed about this rapidly evolving industry.

Soil Preparation

Strike a balance between striving for an ideal seedbed and maximum erosion control. Firm, friable soil surfaces—recommended for seeding—can be susceptible to erosion. Loose, rough soil surfaces slow runoff and provide better infiltration. Surface roughening practices, such as directional tracking and grooving, slow runoff by creating depressions or grooves perpendicular to the water flow. On steep slopes, these practices must be used with other methods, preferably hydroseeding, described in detail below. 

Directional Tracking

Driving a bulldozer or other tracked vehicle up and down a slope leaves depressions perpendicular to the slope (Caution: Driving a tracked vehicle across the slope can increase erosion). Tracking may not be appropriate on clayey soil since compaction can inhibit vegetation establishment. Severe compaction can even prevent no-till drills from penetrating the soil. Concerns regarding compaction decrease when hydroseeding or broadcasting during the dormant season since freezing and thawing will loosen the soil.

Grooving

Pulling a disc or ripper behind a tractor or dozer or back-dragging a toothed bucket with a loader across a slope creates a series of ridges and grooves. If these particular grooving approaches are not feasible, other implements that a department has can be used. Grooving can be more effective than tracking because the depressions are usually deeper and the soil is left looser. 

Statewide Urban Design and Specifications (SUDAS) specifies that grooves should be no more than 15 inches apart and 3 inches deep, though groove depth is subject to differing opinions. Deep grooves improve erosion control but increase the likelihood of seeds being buried too deep to germinate. The seeding method will help determine the appropriate groove depth. One-step hydroseeding calls for deeper grooves since mulch keeps the seed near the surface. If the seed is not incorporated in a slurry when planted, lighter grooving is recommended.

Mulch

Mulch helps prevent splash erosion and holds seeds in place by absorbing rainfall impact and binding soil particles together. Mulching is accomplished by applying straw or hydromulching (i.e., spraying a slurry comprised of water, seed, mulch, dye, and optional fertilizer).

Straw

Dry cereal straw—free of noxious weed seed—can be applied alone or on top of the seed to provide short-term erosion protection, conserve moisture, and suppress weeds. Oat or wheat straw is typically used at a rate of 1–1.5 tons per acre. Straw applied evenly at the correct rate will allow approximately 50% of the soil to be visible. If applied too heavily, seed germination may be affected. It is better to use longer mulch, and some bale processors can be adjusted to apply mulch in this way.

Straw mulch must be crimped or tacked (using a binding agent) in place to keep it on-site; otherwise, it is prone to blowing away on windy days. Roadsides that can be driven on can be crimped. Crimpers (also known as “mulch tuckers” or “mulch discs”) are mounted on a 3-point hitch and pulled with a front-wheel assist tractor. Test runs are necessary to ensure the crimper wheels go into the soil at least three inches—enough to anchor the straw. Properly anchored straw mulch will stand straight and look like oats mowed high.

Tacking is accomplished by adding tackifier to water in a hydroseeder. Tackifier rates vary depending on the brand. Rates are provided on the bottle in pounds per acre. If too much tackifier is added, the mixture will get slimy, preventing the pump from priming. The tackifier solution should be applied evenly on top of the straw until the straw is wet but not running off. The solution will dry and act as an adhesive to hold the straw in place. 

Some IRVM programs use prairie hay harvested from plots or straw mulch plantings. The application method is similar to that for straw, though tackifier rates may vary depending on the dominant species in the hay and how likely it is to blow away. Fewer bales will be necessary because hay weighs more than straw.

Roadside Real Talk

Insights From Roadside Managers and Other Professionals

We use wheat straw. It seems to be longer than oat straw and is typically the same price. I have worked with a local contractor who brings up Kansas wheat straw. We have also used Iowa certified weed seed-free straw. We use an agricultural-type bale processor (no cannon). I use the rate of one-and-a-half tons per acre 1.5 T/acre as a minimum when planning. Just be sure you aren’t blanketing over your seed. You should be able to barely see the ground through the mulch before it is crimped. Tractor, bale processor, and crimper are the equipment I have found most helpful for erosion control. Dollar for dollar, straw mulch is the best money spent on erosion control. 
—Wes Gibbs, Jones County, 2024

With oats or wheat straw, I’ve used seed-bearing stalks to my advantage; it can work as a good cover crop. To apply straw mulch, I use a small bale blower with a gas motor. It does a nice job of shredding up the bales. The process is labor intensive, so I usually only tackle small projects with it. The big round bale blowers/shredders, I don’t have one, are less labor intensive and can cover a lot more area in less time. This method requires mobilization for the bales and a large tractor to run it. I generally mulch at 1,000 to 1,500 pounds per acre. If harvested in the fall just after the seed heads have matured, prairie hay bales will carry enough seed to plant a new site. Some seed supplements may need to be used. I think prairie hay works better than straw. It is just reedy enough that it lays out and kind of locks together. Straw is a lot lighter and doesn’t lay down as well. 
—Ben Hoskinson, Mahaska County, 2024

Our mulch tucker/cultipacker combo is 8 feet wide and weighs 1,600 pounds. We pull it with a 95 horsepower tractor—you might be able to go a little smaller as long as you have sufficient weight in front to balance it when in the “up” position. 
—Wes Gibbs, Jones County, 2024

We always use one-and-a-half tons per acre of straw mulch.
—Ole Skaar, Roadside Development, Iowa Department of Transportation, 2011

We have a couple of organic farmers in the county. When I need straw, I buy it from them. They usually have a field in their rotational plan that will be in oats. I support the concept and like to help them in this small way.
—Linn Reece, Hardin County, 2011

Hydroseeding

Hydroseeding is a planting method that uses a hydroseeder to spray bare soil with a slurry of water, mulch, tackifier, fertilizer (optional), soil amendments (e.g., plant growth stimulant such as microbial inoculant), and seed. See Chapter 5: Seeding for information on how to conduct a successful hydroseeding project.

Hydromulch

Hydromulching combines water, seed, mulch, dye, and optional fertilizer in a slurry. Hydromulch conserves soil moisture and can prevent splash, sheet, or rill erosion. However, hydromulch is not suitable to withstand the shear stress experienced in areas with concentrated flow that causes channel erosion. See Chapter 5: Seeding for additional information on hydromulching as it relates to seeding efforts.

Hydromulching Rates

Hydromulching rates vary by mulch brand. An example mixing rate for hydromulch is 500 pounds of mulch for 1,200 gallons of water. However, this rate can be adjusted depending on the brand of mulch used. Thicker mulches can be applied at a lower ratio. Do not exceed rates recommended on the product label. Rates also vary depending on the equipment being used. Getting the right rate is often a trial-and-error process, but these suggested rates are a good place to start:

• 

  1,000 lbs./acre—a token amount to help carry the seed and show what area has been seeded

• 2,000 lbs./acre—appropriate for most 3:1 slopes
• 3,000 lbs./acre—a very heavy rate for long, steep slopes

Common Types of Hydromulch

As slope length and gradient of the roadside increase, water travels faster, resulting in more erosion. Certain types of hydromulch provide greater erosion control. See Figure 1 for a graphic recommendation of hydromulch by slope length and angle.

Cellulose (Paper)

Cellulose, made from recycled newspapers, magazines, and corrugated cardboard, is the least expensive hydromulch. Its advantages include: greater water retention, quicker mixing, and better pumpability. Cellulose may be the least effective at controlling erosion since it does not have long, interlocking fibers. Avoid applying cellulose too heavily or with too much tackifier (known as the “paper mache effect”), which reduces moisture and airflow to seed. Additionally, some roadside managers have observed that native plants do not grow well when cellulose is used.

Wood Fiber

Wood fiber mulch is produced from milled wood, typically aspen. It is more expensive than cellulose and does not hold as much moisture. However, it has more loft, and the interlocking fibers provide more effective erosion control.

Bonded Fiber Matrix (BFM)

BFM is a wood fiber mulch, usually with elongated fibers, containing various adhesives, binders and synthetic fibers. It retains its strength much longer than traditional mulches.

Wood Fiber/Cellulose Blend

Blended mulch usually consists of 50–70% wood fiber and 30–50% paper products. It falls in the middle of wood fiber and cellulose mulches in terms of cost, water retention, pumpability, and erosion protection.

Mechanically Bonded Fiber Matrix (MBFM) and Flexible Growth Media (FGM)

These mulches contain elongated wood fibers, crimped synthetic fibers, and various adhesives and binders. The crimped fibers provide a strong, mechanical, fiber-fiber-soil bond. The resulting hydromulch slurry does not require any time to go through a curing process to provide erosion protection.

Hydromulch Application

To create hydromulch, mulch is mixed with water and often a tackifier in a truck- or trailer-mounted tank, and the resulting slurry is sprayed onto the site. Tackifiers bind mulch fibers together and bind the mulch fibers to the soil, enhancing erosion protection. Tackifiers are preblended in BFM, MBFM, and FGM products and undergo a chemical process known as “cross-linking,” which prevents rainfall from rewetting and dissolving the tackifier after it is applied. Organic and synthetic tackifiers can also be purchased separately to mix with other mulches. See mixing rates recommended by the manufacturer before application.

Though they are often referred to interchangeably, hydroseeding differs from hydromulching, which involves adding mulch to the slurry. Amendments accelerate seed germination and establishment by adding nutrients to soils that are low in nutrients. Amendments include water-soluble fertilizers, water-storing polymers, and plant growth stimulants. Refer to the manufacturer for recommended mixing rates. Peat moss and compost screenings can also be added as a soil amendment, though little research exists on mixing rates.

Synthetic fibers can be added as an amendment to traditional wood fiber and blended mulches to increase their mechanical bond.

Recommended hydromulching rates are shown in Table 6.1. Maximum slopes, benefits, limitations, rates, and longevity considerations for erosion control methods and further discussed in Chapter 3: Seeding.

Roadside Real Talk

Insights From Roadside Managers and Other Professionals

An important factor that can get overlooked when dealing with sheet erosion is the additional overland flow that may be coming from the roadway. This can really affect hydroseeded areas, and increased rates of hydromulch may be needed. This doesn’t seem to be an issue when using blankets—which makes sense since blankets are appropriate for protection against channelized flow.

SUDAS section 7E-5 deals with mulching to prevent sheet erosion, but we feel they are overly cautious. For instance, they don’t recommend hydromulching on slopes steeper than six-to-one. We recommend looking at manufacturer specs for available products.
—Jim Uthe and James Devig, Dallas County, 2024

I use a wood/paper blend, which I think works the best. The wood I’ve used by itself doesn’t have enough substance. I also use FGMs or BFMs as a supplement to the wood/paper or as a stand-alone.
—Ben Hoskinson, Mahaska County, 2011

Compost Blanket

Typically used on nutrient-poor soil, a compost blanket is a 1–4 inch layer of compost made of a blend of coarse and fine materials. If seed is applied with the blanket, the layer should not exceed 2 inches; establishing roots may not penetrate the underlying soil if the blanket is deeper. Be sure the compost is well-cured, meaning it has finished the composting process and has cooled. If the blanket is applied while the compost is still hot, vegetation may not establish.

A compost blanket should not be used where overland flow is expected. While it will safely absorb rainfall, overland flow can erode the compost. 

Compost blankets effectively prevent erosion and promote seed growth, but only when applied correctly. Specialized equipment, such as a blower truck, is necessary to apply compost blankets properly, so a contractor is typically hired. Due to the high cost of hiring a contractor, the contract for the job should include a guarantee that the job will be done correctly.

Rolled Erosion Control Products

Rolled erosion control products (RECPs) are arguably the best way to stabilize most areas susceptible to channel erosion. They are also used to stabilize slopes. Because RECPs need vegetation to function properly, site conditions must be conducive to establishing vegetation. In extremely nutrient-poor soils or deep shade, riprap (a layer of large stones) or erosion stone may be the best option. Temporary and permanent RECPs are available. Temporary RECPs prevent erosion while the vegetation matures, after which the temporary RECPs eventually degrade. They are more often used on moderate slopes. Permanent RECPs are applied in areas where vegetation alone will not provide enough erosion control, such as steep slopes and areas with a lot of water runoff.

Manufacturers of RECPs provide specifications for their products online. Most manufacturers also provide software for practitioners that helps them determine the appropriate product for a given site. A database of virtually all RECP manufacturers on the market and their specifications is available in the Geosynthetics Specifier’s Guide.

Types of RECPs

Erosion control blankets (ECBs)

Erosion control blankets are temporary, degradable rolled products. They are made of natural or polymer fibers that are mechanically, structurally, or chemically bound together to form a continuous matrix.

Netless Blankets

These consist of fibers stitched together with a biodegradable thread. Because there is no net, this product is typically used in frequently mowed areas and areas where animals could become entangled in netted blankets.

Single- and Double-Net Blankets 

These consist of one or two polymer or jute nettings interwoven with natural fibers—typically straw, coir (coconut), and/or excelsior. In general, netless and single-net blankets are used on slopes or in low-flow channels. Double-net blankets can be used on slopes and in higher-flow channels.

Turf Reinforcement Mat 

Turf reinforcement mats (TRMs) are permanent, non-degradable, rolled products made of synthetic materials. These three-dimensional mats provide immediate erosion protection, enhanced vegetation establishment, and long-term functionality by permanently reinforcing vegetation. TRMs are typically used in high-flow ditch channels and on very steep slopes where unreinforced vegetation may not provide adequate erosion protection.

See the SUDAS Design Manual for the classification of TRMs by material and by their performance in channel and slope applications.

Selecting the Appropriate RECP

Slope Applications

Consulting manufacturers’ general application guidelines (e.g., North American Green) is the easiest way to select an appropriate RECP. Slope length and grade are key selection criteria. When using degradable products, product longevity (determined primarily by material weight) must also be considered. Time of year, soil fertility, aspect (i.e., position of the slope relative to water flow), seed mix, and other factors affect how quickly vegetation establishes. A product may be appropriate for a specific slope length and grade, but if installed over a planting in poor soil, it may deteriorate before vegetation establishment.

Manufacturer software (e.g., North American Green, Profile Products, American Excelsior) is also used to select products for slope protection. Users enter slope length and grade, surface condition of the soil, and the soil erodibility (K) factor for the soil type (found in the NRCS soil survey for each county). The software then suggests multiple appropriate products. Growing conditions and seed mixes determine the appropriate functional longevity.

Channel Applications

When stabilizing a concentrated flow area with temporary RECPs, estimate the amount of flow and time it will take for vegetation to establish. Then use manufacturer specifications to select a blanket with the appropriate strength and longevity.

For large-scale projects, especially in high-flow situations, it may be necessary to conduct the following additional analysis: 

1. Determine channel dimensions, including the width and grade of the channel bed and slopes on each side of the channel.
2. Determine the amount of flow in cubic feet per second (CFS). Flow determination for a given rain event can be done with complex mathematical formulas (performed by engineering staff) or by observing the channel’s watershed and making an educated guess. When protecting channels at culvert outlets, design protection to withstand maximum discharge.
3. Consider the consequences of failure to decide whether the project requires protection against a two-year storm, five-year storm, ten-year storm, etc. According to Certified Professional in Erosion and Sediment Control guidelines, when using permanent RECPs (i.e., TRMs), projects are usually designed to withstand the ten-year frequency, 24-hour duration rainfall event. This is about 4 inches of rain in northern Iowa and 5 inches in the southern part of the state.
4. Enter channel dimensions and flow into the manufacturers’ software, available on their websites, to determine an appropriate blanket.

Installing RECPs

Erosion Control Blanket Installation

• 

  Provide good blanket-to-soil contact by removing debris such as rocks, roots, twigs, and existing vegetation to create a smooth soil surface.

• Trench the top of the blanket to a depth of 6 inches and staple at the bottom of the trench.
• Any overlap between adjacent blankets should be at least 6 inches to prevent gaps between sections.
• Refer to the manufacturer’s specifications for recommended stapling patterns. The area to be protected, often the top of the slope or drainage channel, is used as a reference point and the center point of the blanket is a specified distance, such as 2–3 feet from the reference point. In the absence of recommendations, staple in a staggered pattern using 3-foot centers on a slope and 2-foot centers on a channel.
• In channel applications, center a blanket in the channel bottom to avoid having a seam under the area of maximum flow. At 25–30 feet intervals, place a check strip of staples 2–4 inches apart across the blanket.
• Install additional staples on uneven ground to ensure good soil contact, especially in low points.

RECPs are often maintenance-free after vegetation has been established. Until then, inspect them after every runoff event, adding staples where erosion has occurred. Routine maintenance is easier than repairing and reseeding the large ruts and gullies that can form under improperly installed or maintained RECPs.

Turf Reinforcement Mat (TRM) Installation

• When used in areas that experience weeks-long periods of saturation, provide subsurface drainage to prevent erosion under the mat.
• Anchor mats with 6-inch staples. Use 8-inch staples or stakes in high-flow and loose-soil situations.
• For slope stabilizations, anchor mats with high-performance duckbill or flow transition mat anchors.
• Seed should be drilled or hydroseeded (not broadcast) to prevent small seeds from floating up through holes in the mat and washing away during high-flow events.
• In high-flow situations, BFMs can be used under the mat. Laying sod underneath will provide instant erosion control.
• In slope stabilizations, soil can be placed on top of the mats. In concentrated flow areas, the top layer of soil will wash away unless a straw or erosion control blanket is placed on top.
• TRMs can be infilled with BFMs and FGMs in both channel and slope applications.

Roadside Real Talk

Insights From Roadside Managers and Other Professionals

We had heard at one time that forbs germinate better under straw than erosion control blankets, but we’re starting to become skeptics on that claim. For instance, we just inspected a project where we used an erosion control blanket, and there were just as many partridge pea seedlings in the blanketed areas.

TRMs can stabilize very steep slopes, but in a typical county roadside setting, it may be cheaper to buy more right-of-way, grade it to a general slope, and stabilize it by hydroseeding or seeding/mulching.
—Jim Uthe and James Devig, Dallas County, 2024

If you’re doing a lot of RECP installations, get a staple gun. It’s worth the money! And if you need to cover a lot of surface area, I suggest the 16-foot rolls versus the more common 8-foot rolls). They’re still fairly easy to handle and they cut your installation time and labor almost in half. 
—Wes Gibbs, Jones County, 2024

We do not use straw or straw or coir blankets in channels. Those materials don’t absorb water, so the blankets float if rain causes any flow. You might get them to work with sediment logs or lots of staples, but that isn’t cost-effective. Nothing beats good wood erosion control blankets.
—Ole Skaar, Roadside Development, Iowa Department of Transportation, 2011

Other

Flow Transition Mats

Flow transition mats are an environmentally sound alternative for riprap or concrete in the transition area between flow outlets and channel flow. The semi-rigid, plastic mats— approximately 4 feet by 4 feet and a half-inch—have holes that allow vegetation to grow. The mats are installed on top of a TRM in areas of high scour, such as culvert outlets. Flow transition mats can provide better protection than riprap, and installation is an easy, one-person job. Here are some tips for the installation of flow transition maps:

• When placing transition mats on top of the fill, make sure the area is well-compacted to prevent failure from settling.
• Use subsurface drainage in areas that experience long periods of saturation.
• For best results, place sod underneath the TRM.
• If sod is not used, high-flow events could cause erosion before vegetation establishes. To help minimize erosion, install a staple check strip in the TRM directly downstream from the transition mat.
• Check mats after every runoff event during the first two seasons to make sure anchors are still tight.

Roadside Real Talk

Insights From Roadside Managers and Other Professionals

Flow transition mats can be used as a riprap alternative for channel protection if flow occurs only during larger rain events. The channel needs to dry out at times so vegetation can establish.
—Ole Skaar, Roadside Development, Iowa Department of Transportation, 2011

IRVM programs will be responsible for containing eroded soil on the project site. Basic sediment control products likely to be used on county rights-of-way are described below.

Wattles, Sediment Logs, and Filter Socks

Wattles and sediment logs are tubes of straw, coir, or wood fibers encased in burlap or degradable plastic netting and anchored in the ground by wooden stakes. Both filter sediment and slow down water flow. Wattles and logs containing densely packed material—especially straw—are good as slope interrupters. Wood fiber logs are more porous and less likely to float, making them better suited for ditch checks. Both are good for perimeter applications and inlet protection.

Filter socks are degradable tubes filled with compost. They are generally used for perimeter control or at intervals along a slope to capture sheet flow. Polyacrylamide (PAM) may be added to the compost to enhance sediment control. PAM captures clay particles, creating cleaner runoff.

Wattles, sediment logs, and filter socks are usually easy to install and can be put on bare soil or over erosion control blankets.

Silt Fence

Silt fences are geotextile barriers trenched into the ground and supported by posts. They are useful on perimeters and in channels with relatively low flow. As runoff passes through the fabric, silt fences filter out small amounts of sediment. They must be kept clean to function properly and are removed after final stabilization. Silt fences are easy to install and relatively inexpensive.

Silt fences are ineffective in high-volume flow areas and should not be used as check dams, which would be ineffective and can cause more erosion. 

Improper installation of silt fences, which is common, renders them ineffective. For proper installation techniques, follow up-to-date specifications.

Check Dams

Check dams should be constructed across the water flow using clean rocks, permeable plastic berms, or similar products. Unlike silt fences, check dams do not cause water to dam up. Instead, they let water pass through, slowing its velocity and dissipating its energy.

Sedimentation can occur on the upstream side of check dams. If sedimentation becomes too heavy, check dams will turn into waterfalls and may be rendered ineffective. Monitor check dams and excavate the upstream side if necessary.

Plastic berms should not be placed in areas where they would be susceptible to filling with debris (e.g., corn stubble from a field waterway). One heavy rain can cause these berms to fill, causing the water to dam up.

Improper design of check dams, which is not uncommon, renders them ineffective. Follow current design specifications and account for the individual characteristics of each site.

Roadside Real Talk

Insights from Roadside Managers and Other Professionals

If a rain event is relatively small, silt fences will function properly as a check dam. But, small rain events typically cause little to no erosion. Silt fences may be good for PR, but they create a point of failure for the project. A roadside is essentially a headwater stream. Stream dynamics show that flow equals the area times the velocity. When the water from a flat, six-foot wide channel is concentrated into a width of typically less than a foot at the low point of a silt fence, the water’s velocity increases substantially, thus erosion is caused instead of prevented.
—Jim Uthe and James Devig, Dallas County, 2024

Rock check dams should mostly be below ground. The waterfall problems can be eliminated if the check doesn’t extend above ground level.
—Wes Gibbs, Jones County, 2024

Soil Characteristics

• NRCS Web Soil Survey
• National Cooperative Soil Survey Soil Characterization Data

Manuals

• Erosion and Sediment Control Field Guide
• Iowa Statewide Urban Design and Specifications Design Manual–Chapter 7: Erosion and Sediment Control

Erosion Control Products

• American Excelsior Company
• ASP Enterprises
• Mat, Inc. Erosion Control Products
• terrafix®
• North American Green
• Profile Erosion Control Products
• Ramy Turf
• Stormwater Supply
• ECBVerdyol
• Western Excelsior Erosion and Sediment Control Products

Hydroseeder Manufacturers

• Apex
• Bowie
• Easy Lawn
• Finn Corporation
• Kincaid Equipment Manufacturing
• TurboTurf Hydroseeding

Native vegetation is the cornerstone of IRVM and the front-line approach to weed control. Iowa native plants can thrive in tough roadside growing conditions and are naturally adapted to the state’s climate. Their height and deep roots help prevent weeds. If you have the time and trained personnel, keep the natives healthy with the use of prescribed fire. See Chapter 9: Prescribed Burning for more information.

Overusing herbicides weakens all vegetation, making roadsides more susceptible to weed invasion. Herbicide overuse also eliminates desirable and harmless broadleaf species that would otherwise reduce weed invasion by taking up space and outcompeting weeds with similar light and nutrient requirements. In other words, when plant species have similar ecological roles and occupy the same space or niche within the environment, one will outcompete the other. Facilitating the growth of plenty of desired broadleaf species means there are more plants to shade out potential weeds that might creep in. Conversely, leaving a large area of bare soil with plenty of sunlight creates an environment that invites weeds to invade again. For these reasons, IRVM calls for careful spot herbicide use for weed control.

For plant species that need to be managed using herbicides, talk to herbicide sales representatives and other roadside managers to learn more about how to most effectively and strategically use herbicides. The CDMS advanced search has information for all the chemical labels in the industry.

Before resorting to herbicides, consider whether mowing is a viable alternative. The effectiveness of mowing depends on the timing and which species are targeted. The feasibility of mowing depends on the roadside slope and available equipment. Even if the road right-of-way is not suited to mowing with a tractor, spot mowing is still a viable weed control option.

Biological control is a method of managing invasive species using living organisms such as insects, animals, and plants. For example, roadside managers who want to reduce a weed population may purchase and introduce to a weed-infested area an insect species that consumes the weed’s seeds or roots. 

This method of weed control is inexpensive but can be slow to produce results. Biological control rarely eliminates the entire population of a weed in a given area but may reduce the size of the population. The Minnesota DOT recommends using biological control in areas one-third of an acre or larger and avoiding medians and roadsides that will be disturbed regularly.

Some weedy plant species that can be managed with biological control include spotted knapweed (Centaurea stoebe), leafy spurge (Euphorbia esula), and purple loosestrife (Lythrum salicaria).

To find out which insects are used to control a plant species, check recommendations in the Midwest Invasive Plant Network database or another resource that is updated with the latest information. Check to see if the insect you are considering using has any documented history of causing negative non-target impacts by also consuming desirable plants in the same area. Before introducing any insects for biological control, contact the Iowa Department of Agriculture and Land Stewardship to see if you need a permit. To learn more about where to purchase biological control insects, call your local county agricultural inspector, the Iowa Department of Agriculture and Land Stewardship, or search the web for companies that provide biological control insects.

Timing is key to successful mowing and spraying for weed management. Hiring a full-time roadside manager is the best way to provide professional, proactive, and systematic weed control. A roadside manager who is familiar with all of a county or city’s roadsides can better strategize where weed control efforts will be most effective and monitor the results of control strategies over time. Temporary contractors do not have this type of holistic understanding of local roadsides.

There is no such thing as total weed eradication, so it is important to have realistic goals that involve keeping the presence of weeds at a manageable level. Weed species that pose no real threat to agriculture or natural areas should be left alone. Additionally, highly traveled roads should be prioritized.

Annual Weeds 

Annual weeds have a one-year life cycle. They germinate, grow, flower, set seeds, and die in one year or less. They spread only by seed. Common roadside annuals include common ragweed and giant ragweed.

Controlling Annual Weeds

• Mow before the weeds set their seeds.
• Eliminate bare soil and disturbances to vegetation.

Biennial Weeds

Biennial weeds have a two-year life cycle. In the first year, a basal rosette (circular cluster of leaves on or near the ground) is produced. A central flowering stalk elongates in the second year, and the plant dies after seed maturation. Biennials spread only by seed. Common roadside biennials include musk thistle, bull thistle, poison hemlock, wild parsnip, and wild carrot.

Controlling Biennial Weeds

• Mow before the weeds set their seeds for five consecutive years.
• Treat basal rosette plants with herbicides in fall or early spring when results are typically best before their stalks have elongated (at which point they become more tolerant of herbicides) and damage to desirable plants can be minimized.
• Establish native vegetation to deprive biennials of sunlight during their weak seedling stage.

Perennial Weeds 

The lifespan of perennial weeds can vary from a few years to many years. Some perennials spread only by seed, while others spread by seed and a variety of underground reproductive structures. Because of their extensive root systems, controlling such perennials may be very difficult.

Controlling Perennial Weeds

• Treat perennials with herbicides.
• Mow to prevent seed maturation and extend the herbicide treatment window.
• Establish a diverse native plant community.

Noxious weeds are plants that may damage agriculture, recreation, wildlife, or public health. Iowa’s noxious weed law (Iowa Code Chapter 317) gives each county, and specifically the weed commissioner, the authority to order the destruction of weeds classified as noxious by the state. In some counties, the roadside manager also serves as the weed commissioner, while in other counties, the roadside manager and weed commissioner are two separate positions.

The Iowa Legislature established the noxious weed law and lists weeds that were declared noxious in Iowa Code Chapter 317.1A. However, according to Iowa Code Chapter 317.1C, the legislature can modify the list via administrative rule. Therefore, for the most updated list, refer to Rule 21.58.4, “Noxious weeds list,” in the Iowa Administrative Code, Chapter 58 in the Agriculture and Land Stewardship Department section, instead of the list in Iowa Code 317.1A. 

There are two types of noxious weeds listed. “Class A noxious weed for eradication,” which are weeds that are of the “highest priority for eradication of existing infestations and prevention of new infestations.” There are also “Class B noxious weed for weed control,” which are “a priority for preventing new infestations and stopping the spread of the species.” Refer to the resources in the “Weed and Invasive Species Information” section later in this chapter to learn how to best manage the species on the noxious weed list.

Herbicide Labels

Labels explain how to use herbicides effectively while protecting non-targeted plants, the environment, and people (including those applying the herbicide). Reading the label may be the most valuable use of your time related to weed control.

Adjuvants

Adjuvants are substances that are added to the herbicide solution to increase its effectiveness. These products are put in the water tank at labeled rates. The following adjuvant types are often used when using herbicides in roadsides.

Surfactants

These chemical compounds improve dispersion and reduce the surface tension of spray droplets. This results in increased penetration and absorption into the weed.

Crop Oils and Crop Oil Concentrates

Similar to surfactants, these also improve dispersion. The oil keeps leaf surfaces moist longer than water, allowing more time for penetration into the weed.

Stickers

These compounds cause the herbicide to stick to the weed and help prevent the solution from being washed off leaves by rain, evaporation, or runoff.

Drift Inhibitors

When herbicide droplets drift in the air, they tend to move away from their intended weed targets. These compounds reduce herbicide drift and increase spraying accuracy by increasing the size of the droplets sprayed.

Antifoaming Agents

These agents reduce foaming in the tank so it can be filled easily.

Water Conditioners

Ensure that hard water containing a high amount of dissolved minerals doesn’t affect the active ingredient in your herbicides. You can use a simple pH meter or test strips to test the hardness of your water. Water is generally considered hard if mineral levels exceed 120 mg/L.

If you have hard water, mix in a chemical water conditioner with your herbicides. Water conditioners prevent minerals such as calcium and magnesium from interfering with the herbicide’s active ingredient. Read the label on the water conditioner to determine what pH and hardness conditions it can be used with, since this can vary.

Iowa’s noxious weed list includes a few woody species. Additionally, several trees and shrubs that are not listed have nonetheless become troublesome in non-agricultural land throughout the state. In roadsides, all trees and brush are potential safety hazards. The primary goal of roadside tree and brush control is to increase safety on the roads. Safety goals include:

• Providing motorists with unobstructed lines of sight.
• Ensuring visibility of all signs in the roadsides.
• Eliminating immovable objects that can cause a dangerous collision if vehicles leave the road in an accident.
• Alleviating snow drifts caused by the presence of trees and brush.
• Reducing shade where it prolongs ice on the roads.

Most roadside tree and brush control is accomplished mechanically or chemically. However, a correctly timed prescribed burn can also control brush.

For complete brush control information, see Chapter 8: Brush Control, and refer to “Tree and Brush Control for County Road Right-of-Way,” a 2002 manual from the Iowa Highway Research Board and the Iowa Roadside Management Office. 

Resisting outside pressure to apply more herbicides might require educating landowners—or even county or city elected officials—on why spraying would be inappropriate. The following points can be helpful when talking to someone whose weed control philosophy is based primarily on experience with row crops and lawns.

• Roadside weed control bears no resemblance to row crop weed control. Corn and soybeans are annual species maintained in bare soil, a practice that invites weeds and requires continuous cultivation and herbicide use. On the other hand, native seed mixes designed for roadsides create diverse stands of perennial vegetation that prevent weeds by occupying all available space. Overuse of herbicides works against this method of weed control.
• Native prairie grasses and wildflowers may be tall and appear unkempt, but they are the plant species most adapted to Iowa’s climate and growing conditions. Their extremely deep roots enable them to survive environmental stressors, and their unique metabolism allows them to grow tall and thrive during long, hot summers. Because of these characteristics, native plants outcompete weeds.
• Broadleaf wildflowers included in native seed mixes are part of the weed control plan. They occupy a niche in the plant community otherwise occupied by weeds and are not a threat to agriculture.
• A pure stand of any grass is an unnatural condition that is sustainable only through the use of herbicides. Diverse prairie plantings are better able to outcompete weeds and require fewer herbicides than a stand of one species.
• Overuse of herbicides in any roadside creates openings for weeds by weakening grasses and eliminating beneficial broadleaf wildflower species.

Landowner Permits and Letters

According to Iowa Code Section 317.13, counties must require individuals to obtain work permits for the burning, mowing, or spraying of roadsides included in an IRVM plan. These activities must be consistent with the county’s adopted IRVM plan. For a sample of what these permit applications look like, see Appendix 7A: Sample Landowner Work Permit.

Counties may also choose to create permits or request forms for individuals to collect seeds, plant native seed or plants, or manage the invasive species in roadsides bordering their property. Landowners who do not want the roadside vegetation adjacent to their property sprayed with chemicals make up the bulk of these permit applications. For a sample of what these request forms look like, see Appendix 7B: No Spray Request.

Investigating Suspected Landowner Spraying Encroachment

For roadside sites that you suspect have been sprayed, you can contact the Pesticide Bureau at the Iowa Department of Agriculture and Land Stewardship (IDALS). The bureau will send a pesticide inspector who will investigate to determine whether it was a result of direct spraying or drifting. The inspector will issue a report but cannot pursue legal remediation on your behalf; that is in the purview of the county attorney. If you want to pursue monetary damages for a violation of Iowa Code, consult with your county attorney, who can notify the responsible landowner. If the spraying was inadvertent, the landowner or farm operator may have liability insurance that can result in a settlement with the county attorney in 9–12 months. Word gets around, and enforcing Iowa Code related to roadside vegetation sends a message to landowners that there will be consequences for people who spray roadside vegetation.

The Iowa State Association of Counties General Counsel (515-369-7014) is a good resource for questions regarding sections of Iowa Code that apply to roadside vegetation management.

Most counties that execute their weed control plan in-house do so with the following parameters:

• 

  one full-time employee for much of the summer

• two seasonal employees
• one primary spray rig
• $15,000–$30,000 spent on chemicals each year (as of 2024)
• at least half of the county roadsides are managed for weeds each year; often, one-half of the county will be managed one year, then the other half the following year
• herbicide applicator licenses and certifications maintained
• proper herbicide storage
• proper disposal of herbicide containers
• awareness of the latest developments in herbicide and sprayer technology

The benefits of providing in-house county weed control include:

• The county has control over how roadsides are managed. Sensitive areas such as gardens, bee hives, organic farms, prairie remnants, and roadside wildflowers are protected.
• Having someone on staff who can apply herbicides and effectively control weeds is a great asset for roadside managers and county recreation staff.
• When the person executing the plan lives in the county, personal pride and accountability become part of the equation, resulting in a more conscientious effort.

In the early days of IRVM, many counties sent crews into ditches equipped with backpack sprayers to carefully spot-spray weeds. While this method provided good weed control with a minimal amount of herbicide, roadside managers soon learned they could not cover enough of the county since it takes a lot of time to manage weeds on foot.

Since then, IRVM has helped drive the development of spray truck technology that delivers herbicides with the accuracy and control needed to live up to the program’s original principles—killing target species without weakening non-target species or putting too many chemicals in the ground. Progress has been made, not just with more responsive on/off control switches and multi-directional spray nozzles, but also with systems that monitor flow, record data, and significantly reduce operator exposure. As with any spraying equipment, the technology is only as good as the person whose finger is on the trigger. The objective is still to spot spray. Beware of getting comfortable and sitting too long in the cab, which can make you drowsy and more likely to miss problem weeds. Be conscientious, stay alert, and be ready to grab the handheld sprayer and walk to that distant shrub to treat it properly. Never underestimate the value of handheld labor; sometimes, it is still best to put on the old backpack.

Roadside Real Talk

Insights from Roadside Managers and Other Professionals

We don’t spray shoulders, just bridge abutments and guardrails. We don’t spray wild parsnip unless asked or if there’s a really rank patch. Unfortunately, if we tried to spray every parsnip plant, we’d essentially be blanket-spraying many areas. 
—Jim Uthe and James Devig, Dallas County, 2024

I publicize in the paper when we will start spraying and encourage people to call me with locations of sensitive areas—gardens, bee hives, people who have allergies, etcetera. I have “No Spray Zone” signs for willing landowners. 
—Jeff Chase, Des Moines County, 2024

High-diversity roadsides are more robust and more resistant to weeds. Maintain high diversity even if you don’t have the opportunity to establish natives. Don’t spray species that are not creating problems. Our goal each season is to cover half the county for noxious weeds and the other half for brush. Most of the weed spraying is noxious thistles and teasel. When spraying brush, we try to cover areas in which brush and trees were cut the prior winter to catch any regrowth.  

We have isolated patches of garlic mustard that get sprayed. However, what exists in the ditch is usually spillover from the woods. What makes it to the ROW is just the tip of the iceberg, so I don’t get too excited about chasing it down. We have plenty of parsnip that, historically, were sprayed every year. Still have plenty of it. We currently do not spray parsnip. 
—Wes Gibbs, Jones County, 2024

I feel like addressing the spraying of noxious weeds was one way we built some goodwill as we have aggressively attacked those during the peak months of June and July.
—Sean O’Neill, Sac County, 2024

I mostly use the web or my sales rep for technical support. It’s too hard to maintain up-to-date, written information on the most effective herbicides for each species. But like anything else, the advice is only as good as the source.
—Josh Brandt, Cerro Gordo County, 2009

Counties and cities typically use truck- or trailer-mounted chemical injection (high-end) or tank mix (basic) herbicide spray systems. The following is a description of one county’s two spray rigs, which are representative of the range of equipment available.

Our high-end unit is a chemical injection system. This unit has a GPS to record the rate, type, and amount of chemical used. We download that info to our desktop and print our reports. Our system has three injection pumps with three chemical tanks and a 300-gallon water tank, all on a skid for easy loading and unloading on the pickup. All the controls and the electric start are mounted in the cab on a computer stand. We have three bumper-mounted spray nozzles—6 feet, 20 feet, and 30 feet—and a hose reel with 300 feet of hose in the back. We like this unit because we can easily switch chemicals to spray something else, and one person can load and unload everything in less than an hour. A downside of this system—we can only use liquid chemicals, otherwise, everything gets plugged up.

Our basic unit can also be loaded in the truck by one person. Just about any chemical can be used because it’s a tank mix system with an agitator in the tank. It has a 200-gallon tank, also on a skid, run by a five-and-a-half horsepower motor. We have two nozzles, a 6-foot and a 30-foot on the right front bumper. There is a hose reel in the back with 200 feet of hose. There’s no GPS on this system, so we have to keep track of everything. We mounted switches in the cab to run the nozzles, but we have to get out to turn the system on and off.

Another type of truck-mounted herbicide spray system used in roadsides is invert emulsion. It was developed to reduce herbicide drift and volatilization by producing large droplets of water surrounded by oil. The droplets do not dry as fast as water, so leaf penetration is greater. Invert emulsion sprayers do not work with all types of chemical products; liquid formulations usually work best. Due to the oil used in invert emulsion, roadsides treated with this method should be monitored for phytotoxicity, which is when a chemical substance hinders the growth of plants such as perennial grasses.

Spray Nozzles

Bumper-mounted spray nozzles or raised, multi-section, nutating spray nozzles are typically used on county rigs. Here is one county roadside manager’s description of both nozzle types:

A multi-section, nutating spray head allows a mindful operator to choose which section of the ditch to spray—in two, four, or six-foot increments out to 30 feet. A system with multiple bumper-mounted nozzles can spray different distances, too, but they tend to spray everything up to that distance. The multi-section system uses less herbicide primarily by hitting a narrower band. But if operators of multi-section systems hit all seven switches every time they spray a single thistle—just to make sure they don’t miss—there won’t be much reduction in herbicide. Ultimately, a good operator still makes the difference.

Spray System Components With Options/Suggestions

Installation Method

• skid-mounted
• permanent truck or trailer

Water Tank

• 300–750 gallons (typical)
• 1,000 gallons (requires a commercial driver’s license to operate)

Chemical Mixing System

• tank-mix system with mechanical agitation (chemicals added manually to the large water tank) 
• chemical injection system with 2–3 separate chemical tanks (chemicals mixed with water after passing from the tank)

Water Pump

• roller
• piston
• centrifugal
• diaphragm 

Water Pump Motor

• 5.5–11 horsepower

Injection Pumps

• application of at least 20–40 gallons per minute

Hose Reel

• 

  capable of storing a hose 200–300 feet long and ½ to ¾ inches in diameter of the threaded fitting inside the hose (electric rewind recommended)

Propellant Method

• spray gun to deliver the spray
• spray wand attached to a hose to extend the reach of the spray gun
• one-sided truck-mounted spray heads
  • 2–4 bumper-mounted nozzles 
  • raised nutating head with multi-direction spray sections

Console

• 

  featuring controllers, switches, GPS, computer

Controller

• with adjustable application rate

Flow Meter

• records herbicide application data

GPS

• maps spray location
• GPS units may come with additional software that is installed on a tablet or computer 

Backpack Sprayers

The backpack sprayer is the best way to reduce herbicide use and target specific invasive plants, especially in diverse wildflower plantings. Consider the following tips:

• Use a low-volume backpack sprayer. Birchmeier and Solo are brands trusted by roadside managers.
• A 4-foot wand reaches right down to the target plant.
• Herbicides made to kill broadleaf weeds will also kill wildflowers.
• Transline works on tough weeds without a lot of residual effect.
• Follow the spray mixing rates on the label.

Roadside Real Talk

Insights from Roadside Managers and Other Professionals

We have an 800-gallon tank. We like using a lot of water; bigger droplets equals less drift.

Our spray rig came with an 8-horsepower engine which failed due to a mechanic’s error and was replaced with an 11-horsepower  due to availability. It lasted 8 or 9 years and was replaced with a 13-horsepower, which lasted 8 or 9 years, too. We are on our second 13-horsepower HP now. Our pump is a Hypro centrifugal pump with an electric clutch. The Legacy 6000 can be used as a datalogger and rate controller. When our old datalogger died, we just piggybacked the Legacy onto our existing rate controller because it was a lot less work than redoing everything. We recommended a minimum of two chemical injection tanks, one brush and one thistle. We used to put 2,4-D in our third tank for use on large patches of various undesirable weeds—giant ragweed, hemp, crown vetch, parsnip, hemlock, etcetera. Now we put a low rate, 5 ounces per acre, of Method herbicide in the third tank and use it in addition to our brush mix when spraying honeysuckle.  
—Jim Uthe and James Devig, Dallas County, 2024

Excellent up-to-date information about controlling invasive species is available on the web. Take advantage of the following websites.

Weed and Invasive Species Information

• 

  Iowa Weed Commissioners: This website includes weed identification brochures from nearby states and the Hawkeye Cooperative Weed Management Area. It also has presentations about products and calibration sheets.

• Midwest Invasive Plant Network Invasive Plant Control Database: Information on controlling common Midwest invasive plants.
• Invasive Plant Fact Sheets: This information is from the Pennsylvania Department of Conservation and Natural Resources, though many of the species covered are also troublesome in Iowa. The fact sheets discuss the identification, distribution, and biology of invasive plants.
• Invasive Plants | Missouri Department of Conservation: These pages outline the identification and control of many invasive and troublesome species common to Iowa.
• Weed Science | University of Wisconsin-Madison: Good general invasive plant management information and fact sheets from the University of Wisconsin’s Integrated Pest and Crop Management program.
• Invasive Plant Atlas of the United States: Many of Iowa’s invasive/nuisance plants are included in this list of invasive species of the Eastern United States. Pictures and control methods are provided.

Herbicide Information

• Herbicide Effectiveness on Invasive Plants in Wisconsin: This table details the effectiveness of 35 herbicides on 32 different invasive plants based on research and field observations.

Herbicide Suppliers

• Corteva Agriscience
• Envu
• Midwest Spray Team & Sales, Inc.
• Nutrien Solutions
• Van Diest Supply Company 

Herbicide Spray Equipment and Software Companies

• AgTerra Technologies
• C&R Supply
• Dultmeier Sales
• SpraySync
• Wanner Hydra-Cell

The lower dose of 2 ounces of aminopyralid for Canada thistle seems to knock them out while not visually impacting common milkweed that may be within or close proximity to the thistle patch. Here in Black Hawk County we have found several problem weeds and brush. This year we started to use aminopyralid, triclopyr, metsulfuron-methyl for our brush and broadleaf herbicide, and we also have several spots of Japanese knotweed that we sprayed with triclopyr and completely killed. We sprayed it early to mid-summer and only a handful of small re-growth occurred. Then we also sprayed the regrowth, and it’s now dead. 
—Griffin Cabalka, Black Hawk County, 2024

Consider hitting teasel rosettes again in the fall after the main spraying is done because you just don’t have time to hit everything during the season. Rosettes can be missed and you can go back in the fall in bad areas and hit what you missed and get ahead for the next growing season.
—Josh Batterson, Wapello County, 2024

With spring burns for multiple years in a row up to four years with follow-up mowing and spot spraying, we saw a huge reduction, close to 90 percent, in wild parsnip in a native plot we manage using this technique.

Mow or cut Japanese knotweed mid-summer, then apply aminopyralid in the fall right before the first frost. 

To manage phragmites, use a strong solution of glyphosate mid-summer with yearly follow-up and re-treat.

For leafy spurge, use two applications of potassium salt of aminocyclopyrachlor at least two weeks aparat in the spring and a fall application if possible.
—Lakota Kirst,  Cerro Gordo County, 2024

Aminopyralid achieves a very high level of control on thistle with minimal disturbance to grass. A custom mix for spraying cut stump, cut stubble, and basal is better than premixed stuff.
—Wes Gibbs, Jones County, 2024

Several IRVM plans state that all woody vegetation in the right-of-way is subject to removal unless otherwise directed by the engineer. Some counties list exceptions to woody vegetation removal. For example, Linn County’s IRVM plan includes a provision that some brush and trees may remain undisturbed in the right-of-way under the following conditions:

• The vegetation’s proximity to existing private fences or other structures prevents removal without causing damage to private property.
• The vegetation is located on or behind non-traversable back slopes and banks.
• The vegetation is located a safe distance away from the guardrail.
• The vegetation is located more than 30 feet away from the road.

Within the right-of-way, the priorities for brush removal can vary. For example, some counties prioritize controlling brush near the edge of the road, down the foreslope, and in the ditch bottom. Brush in these areas where errant vehicles are most likely to enter the roadside poses the greatest safety risk.

Other counties prioritize brush removal depending on the type of road. For example, near hard-surface roads with high traffic volumes, the county removes brush from the edge of the road to the ditch bottom. Near Level B roads (those that receive minimal maintenance) and dirt roads, which have low traffic volumes, the county does not prioritize brush cutting or mowing unless the trees and limbs contact vehicles on the road.

Most brush control occurs during winter, which is the most effective time to employ many of the chemical and mechanical brush control methods to kill woody vegetation. Roadside managers and their assistants also have more time to dedicate to brush control, unlike during the growing season, when they are busy managing herbaceous vegetation. 

Some IRVM plans leave the timing of brush control open-ended. It may vary according to staff and resource availability or the danger and sight impairment posed by trees and shrubs in the right-of-way. 

Protecting Endangered Bat Habitat

The Indiana bat (Myotis sodalis), the northern long-eared bat (Myotis septentrionalis), and the tricolored bat (Perimyotis subflavus) are listed as endangered under the federal Endangered Species Act. This designation provides protection for their habitat, which includes forested areas of large portions of Iowa during the growing season. As determined by the U.S. Fish and Wildlife Service, suitable habitat for these species includes forests containing live trees or snags equal to or greater than 5 inches in diameter at breast height (dbh) with cracks, crevices, or hollows. These trees can occur in linear settings such as fencerows and are considered suitable habitats if located within 1,000 feet of other forested or wooded habitats. Trees in highly developed urban areas are not deemed to be suitable habitats.

To avoid impacting these bats, counties could adopt a policy requiring the removal of trees at least 5 inches dbh between October 1 and March 31, when the bats are hibernating in caves and abandoned mines. According to the U.S. Fish and Wildlife Service, if trees must be removed outside of this time frame, the months of April, August, and September are preferred in order to avoid the times when bat colonies are most dense and young bats cannot fly.

Migratory Bird Treaty Act Compliance

The Migratory Bird Treaty Act prohibits the killing of protected migratory birds without prior authorization by the U.S. Fish and Wildlife Service. The act protects all native North American birds and their nests, which includes over 1,000 species. Before roadside vegetation management is implemented, precautions should be taken to prevent the disturbance of active nests (those with eggs). Active nests will most likely be present from April 1 to July 15.

History

The era of using chemical methods for controlling roadside brush began in 1945 with the commercial availability of 2,4-D. These early days of roadside vegetation management consisted of blanket spraying of herbicides across vast swaths of roadside vegetation. However, because this method did not attempt to target only specific unwanted brush species, it also killed desirable vegetation. Without long-lived perennial vegetation competing with undesired vegetation, annual weeds and short-lived perennials grew and dominated roadside ditches. Additionally, early herbicides, such as Agent Orange, were also associated with increased risk for various types of cancer.

From the late 1980s until now, many Iowa counties have adopted IRVM principles to manage their roadsides. In the 2000s, cities also began to practice IRVM. Because the blanket spraying techniques described above were ineffective in terms of safety and effectiveness, IRVM emphasized strategic spraying to manage weeds and brush. 

Timing of Strategic Herbicide Application

Some programs do not cut or mow in areas where herbicide is applied to allow time for the chemicals to completely kill the treated shrubs and trees. Regardless of the application method used, treating woody vegetation when it is young is more cost-effective and takes less time than using mechanical equipment to remove large trees and shrubs. Killing trees when they are young and small also prevents residents from becoming attached to the trees and objecting to their removal. 

Worker Safety Around Chemicals

Though not part of a brush control strategy, pesticides are another chemical that may occasionally be used in some IRVM plans. Roadside managers should be aware of worker safety concerns related to herbicides and pesticides. Federal and state laws require that people using pesticides on public property, such as the right-of-way, be certified as pesticide applicators. For information on pesticide applicator certification, consult the Iowa Department of Agriculture and Land Stewardship. 

Safety Tips When Applying Chemicals

• Always read the label; this is critical to ensure you use the product correctly and take appropriate precautions.
• Follow these personal protective equipment tips:
  • Wear clean clothes, such as a long-sleeved shirt, long pants, closed-toe and nonporous shoes, and chemical-resistant coveralls.
  • Wear safety goggles or glasses to protect your eyes.
  • Wear a cap or hard hat to protect your head.
  • Wear heavy rubber (not cloth) chemical-resistant gloves.
    • Tuck the gloves inside your shirt sleeves.
    • If the label indicates they are safe to reuse, wash gloves with soap and water after every use.
    • Disposable latex gloves can be used, but must be discarded after every use.

Sensitive Areas

Consider using non-chemical methods to control woody vegetation in the following areas that are easily affected by chemical herbicides:

• row crops
• organic farms
• windbreaks
• bee habitat, including nearby flower sources
• homes and yards
• flower and vegetable gardens
• landscape trees
• pets
• human health
• residences housing people with lung conditions such as asthma or COPD
• prairie remnants and reconstructed prairies
• decorative flowers planted in the ditch by residents
• other plant communities
• trails in the right-of-way

If it is determined that herbicides must be used, communicate with landowners who may be affected and take extra care to avoid chemical drifting.

Pesticide applicators must follow what is known as Iowa’s “Bee Rule,” Iowa Administrative Code Chapter 45 21–45.31(206). Under this rule, commercial pesticide applicators cannot use pesticides labeled as toxic to bees for blooming crops within one mile of a registered apiary (a collection of beehives) between 8 a.m. and 6 p.m. Beekeepers can take legal action if they believe their site has been affected by pesticide spray.

Pesticide applicators must also avoid spraying near organic farms, as drifting onto the farm could lead to decertification of the farm’s organic status. For the farm to be certified organic, it must be chemical-free for three years. 

Pesticide applicators can identify sensitive areas, including organic farms and apiaries, by checking the Iowa DriftWatch map, which is available as a website and on the FieldCheck by FieldWatch mobile app. Applicators can register by email if they want to be notified when new sites are added near a given location.

Some counties have a no-spray program, where landowners adjacent to county roadsides may request that the roadside not be sprayed. The landowner must agree to remove noxious weeds using non-chemical methods. Consult with the county engineer for details about local policies.

Foliar Spray Treatment

Foliar spray is used on growing plant leaves, stems, trees, and shrubs shorter than 10 feet tall and too numerous or small to cut efficiently. The herbicide absorbed through the leaves and stems moves through the plant, killing the growing parts and preventing regrowth. The lower canopies make it easier to completely cover the shrubs and trees with herbicide. However, it is not recommended for taller trees because it can be more difficult to obtain full coverage on them, and spray drift into nontarget areas is more likely.

Foliar spray is applied during the growing season from May to October to increase maximum absorption. Use extra caution to avoid spray drift onto private property or the vicinity of a waterway such as a creek, river, or drainage way. If spray drift is a concern in sensitive areas, consider using basal bark spray or cut stump treatment instead.

Low-Volume Foliar Spray

Applicators use handheld or backpack sprayers to treat tree foliage with a fine coating of herbicide. This method improves precision, saves money on chemicals, and reduces damage to nontarget vegetation. This method is more appropriate for smaller areas of vegetation than high-volume foliar spray.

High-Volume Foliar Spray

Applicators use mechanically powered equipment, such as truck-mounted sprayers with high-pressure nozzles, to treat the foliage of target shrubs and trees using 25–200 gallons or more of herbicide per acre. This method can be appropriate for large areas of dense vegetation.

Some more commonly used herbicides for foliar spray include triclopyr, triclopyr choline, metsulfuron-methyl, aminopyralid, and aminocyclopyrachlor. Before mixing herbicides, check the labels for proper instructions.

Frill Treatment

Also known as “hack-and-squirt,” this method of controlling invasive trees involves cutting the bark at least one inch deep to create frill cuts where herbicide can be applied to the cambium (the tissue layer that is the growing part of the trunk). Frill treatment is appropriate for large trees or trees at least one inch in diameter, where foliar spray is not feasible because of hard-to-reach brush and trees or nearby sensitive areas. The best time of year to use frill treatment depends on the herbicide; some can be applied at any time of the year, while others are applied only during periods of active growth. Spring, when sap flow is heavy, is typically avoided because the sap can reduce herbicide effectiveness.

To execute a frill treatment, cut the tree below the last live branch. Use a hatchet or other sharp blade to make downward cuts or frills at a 45-degree angle around the tree trunk to reach the cambium layer (the layer of cells that produces new wood and bark). Space the cuts evenly around the trunk, leaving spaces between them so the herbicide can move throughout the tree. For larger trees, a one-inch space between cuts is recommended.

The cuts should be immediately filled with herbicide from a spray bottle or backpack sprayer. The chemical is absorbed into the tree’s vascular system and transported throughout the tree, resulting in its death. Water-soluble herbicides like clopyralid, glyphosate, imazapyr, and triclopyr may be used. Read the label to ensure the product is approved for frill treatment.

Waiting at least a month after treatment before removing the tree ensures the herbicide reaches all parts of the tree and completely kills it. After the tree is dead, it can be felled using appropriate tree-felling techniques.

Basal Bark Spray Treatment

This efficient, targeted method involves spraying herbicide on live bark near the base of a plant. The bark does not need to be cut. An oil carrier in the herbicide solution facilitates penetration through the bark into the plant.

This method is more likely to be used within native plantings and areas that cannot be cut with equipment, such as brush in fencelines. Basal bark spraying is effective on shrubs and trees 2 inches or less in diameter at the base of the tree because the bark of these younger trees is thin enough for the herbicide to penetrate. The bark should be sprayed 12–18 inches above where the shrub or tree meets the ground. Using a dye to mark treated stems may assist in tracking which plants have been treated. A penetrating oil should be added if it is not included in the dye. Check the label for the recommended ratio of chemical to oil. Basal bark spray treatment is a slow process because trees must be treated carefully to avoid affecting nearby vegetation. It can take several weeks to see signs of herbicide impact. Depending on the species, it may take several months for the plant to completely die.

As with frill treatment, the best time of year for basal bark spray depends on the herbicide used. Some IRVM plans say the best treatment window is between November and March. If there is so much snow on the ground that you cannot reach the base of the tree, it is not a good time for basal bark treatment. Times of heavy sap flow should also be avoided. Spraying when the weather forecast calls for dry conditions for four days can prevent rain from washing the herbicide into adjacent vegetation, which could create a “ring of death” of dead vegetation around the base of the tree that has been sprayed.

The applicator uses a backpack or handheld sprayer to spray herbicide on the stems of target trees. The spray is applied around the entire circumference of the tree to the lower part of the trunk, about six inches off the ground, where the bark is thinner. After the herbicide is absorbed, it moves throughout the plant and kills it.

Examples of herbicides used in basal bark spray include triclopyr, triclopyr + 2,4-D, aminopyralid, aminocyclopyrachlor, and imazapyr. Check the labels for proper instructions.

Cut Stump Treatment

For this method, vegetation must first be cut at the stump to within 3–4 inches of the ground and then treated with herbicide, which enters the cambium and moves into the roots. Cut stump treatment quickly targets and kills the root systems of trees or shrubs. Stumps that are not treated with herbicide will typically resprout. Cut stump treatment is also used for woody vegetation larger than 6 inches in diameter that is too large for basal bark spraying. Treatment can be done at any time of year when the sap is not flowing, but many roadside managers prefer October through early March for the best results.

Use a chainsaw or other equipment to cut the tree as level to the ground as possible so the stump will not affect any vehicles entering the area. Treat the exposed stump within a few minutes of cutting. Otherwise, the stump can seal itself off and prevent the herbicide from penetrating. Applying herbicide immediately also avoids missing stumps. Apply the herbicide directly to the lighter-colored greenish cambium tissue layer on the stump's outer edge. 

Triclopyr and glyphosate products can be used in sensitive areas because they are relatively nontoxic to aquatic wildlife and leach slowly through the soil. Picloram, potassium salt of aminocyclopyrachlor, and aminopyralid can be used in other areas; they are not appropriate for sensitive areas because of their greater toxicity in aquatic environments and ability to stay in the soil for many months. Potassium salt of aminocyclopyrachlor and aminopyralid can effectively treat species that are tougher to kill. Use herbicides labeled as safe to use near waterways when treating brush adjacent to sensitive aquatic areas.

Mechanical methods are the most appropriate for controlling woody vegetation on a large scale. If trees or brush on private property need to be cut as part of the plan for a particular site, a signed written agreement should be obtained before the work is performed.

Equipment

Excavator

While excavators are often used to move large amounts of earth and rock, they can also be used to clear trees and brush. The excavator operator can use the large bucket attached to the hydraulic arm to dig around the root ball of a tree to grab it and pull it out of the ground. This method of permanently removing the plant is known as “grubbing.” A disadvantage of grubbing is the soil disturbance it causes, which can result in erosion and the growth of invasive weeds unless the site is reseeded with vegetation. The cost of reseeding should be considered. Alternatively, to minimize soil disturbance, the cut stump treatment can be applied. 

For smaller brush, the excavator bucket teeth can be used to rake woody debris into piles. Contracting with an outstanding excavator operator can facilitate the efficient clearance of large trees and brush.

Bulldozer

Bulldozers can be used to push over trees with their large blades. Invasive species may invade the bare ground left in areas treated by bulldozers unless the ground is reseeded.

With both excavators and bulldozers, it is important to have skilled operators who know how to properly fell a tree so it does not damage equipment or injure people.

Bucket Truck

A bucket truck can lift roadside managers into the tree and shrub canopy in areas where steeper grades limit access by foot or branches on tall trees overhanging the road need to be managed. While in the bucket, staff may trim branches with a chainsaw or pole pruner.

For safety, employees should wear a fall-restraint safety belt system or a full-body harness fall arrest system that tethers the worker to the lift. Follow Occupational Safety and Health Administration guidelines (1910.333(c)(3)(i)) that call for remaining a safe distance from powerlines. 

Boom Mower

A boom mower attaches to a tractor or loader and can be used to cut brush, small trees, and grass in areas that are difficult to reach, such as behind guardrails and down steep slopes. The hydraulically operated arm can be raised, lowered, and angled as needed.

Forestry Heads

A forestry head is a cutting head that can be attached to a skid steer, tractor, excavator, or bulldozer. Forestry mulchers are a type of forestry head that uses a rotating drum or blades to cut and grind woody vegetation, turning it into mulch. Depending on the model, forestry heads are designed to mulch much larger vegetation. They can cut and mulch trees up to 15 inches in diameter and mulch smaller trees up to 8 inches in diameter. However, some species are more stringy and difficult to cut and mulch with a forestry head (e.g., elm and hackberry).

Forestry heads can be used to remove brush and grind stumps. They are more powerful than handheld brush cutters (see the “Brush Cutters” section below) and more suitable for clearing dense brush and trees. Forestry mowers, another type of forestry head, can typically handle woody vegetation up to 8 inches in diameter, although some models can cut larger vegetation.

There are two types of forestry mowers, rotary and drum, which are described separately below. The necessary maintenance is minimal for both, consisting of greasing and rotating the blades or cutting teeth. Carbide cutting teeth last longer than blade systems and may be preferred unless shrubs are the primary vegetation being cut. Some roadside managers have noticed that the teeth can last a long time if they are kept high enough during the cutting process so that they do not get too dirty with soil, and if the teeth are cleaned regularly.  

Rotary Forestry Mowers

These mowers employ a spinning set of blades or teeth on a rotating drum to cut and shred vegetation. They can clear more acres in a day than drum forestry mulchers. However, rotary-style mowers may throw large chunks of mulch onto the road, which can be dangerous if left there. Chunks may also be thrown into adjacent farmers’ fields, which can impact farming efforts and upset the farmers. Roadside managers should set aside time after mowing with rotary forestry mowers to pick up any flung chunks.

Drum Forestry Mowers 

These mowers use a cylindrical drum with multiple cutting teeth that rotate vertically to mulch material. They are slower than rotary forestry mowers but leave behind a cleaner work area by producing smaller chips that are not thrown as far as the chunks produced by rotary forestry mowers. Drum heads are also better at grinding stumps, including large stumps, into chips by going over them multiple times. The drum can then be put into the ground to incorporate the chips into the soil.

Tree Shear

Tree shears can be placed on skid steers on a smaller piece of equipment than a forestry head. They shear trees with a pair of blades, which is effective for cleanly cutting small-diameter trees while producing minimal debris. Because of their precision, tree shears can be useful for selective tree removal. Depending on the species, some trees removed this way may regrow, and the stumps may need to be treated with herbicides so they do not regrow.

Wood Chipper/Tree Shredder

A wood chipper, also known as a tree chipper, cuts branches into smaller wood chips for mulch or compost, making it easier to transport tree waste to the landfill or public works department. Similarly, a tree shredder processes smaller plant material, such as small branches and twigs. When it comes to these two machines, it is more common for roadside managers to use wood chippers. The woody vegetation that goes into wood chippers or tree shredders is cut down using equipment such as loppers, bow saws, chainsaws, or forestry mowers. The type of equipment needed will depend on the size of the shrub or tree. Roadside managers then feed the branches into the wood chipper. For trimming small woody roadside vegetation, a wood chipper with a capacity of 9 to 12 inches will probably be sufficient. A chipper with a capacity of 15 to 19 inches is better for large trees. Check with an equipment dealer to ensure you get the right capacity for your needs.   

Diesel wood chippers typically cost more than gas wood chippers, but usually use less fuel, are more powerful, and can handle larger branches. While diesel wood chippers may be more durable than gas wood chippers, they also have a more complex design and may require more maintenance.

Another choice to make when buying a wood chipper is whether to buy one with a drum or a disc. Drum chippers use a rotating drum with knives, while disc chippers use a disc with blades. Drum chippers can quickly process large amounts of wood. Disc chippers are better at producing more uniformly sized chips. With their larger size and greater power, drum chippers typically cost more than disc chippers. 

Wood chippers can be towed behind a dump trailer or box-bed truck. This allows for chipping and mulching directly into the truck bed and easy dumping of the mulch afterward.

A wood chipper winch (a mechanical rotating spool for pulling a cable attached to an object back toward the spool) pulls large and difficult-to-reach branches and limbs up to the chipper, requiring less manual labor from the chipper operator. It is handy when pulling brush from narrow locations that a wood chipper cannot access, such as the roadside. It also makes the work safer, since operators spend less time near the chipper’s feeding mechanism. 

Brush Mower

These mowers, also known as “rotary cutters,” use wedge-like blades to cut through thick vegetation, such as small trees and bushes, and are effective for clearing large, overgrown areas. Tow-behind brush mowers can be used with ATVs, UTVs, or lawn tractors. Brush mowers can throw roadside debris, such as metal cans, at high velocities toward the road and the mower operator. To reduce this safety risk, check chains (also known as “deflector chains” or “rock guards”) or heavy mesh screens can be installed on the front and back to deflect or slow down debris. 

Brush mowers are also available as large, heavy, and powerful walk-behind lawnmowers. They use a heavy blade to cut through woody brush and saplings. Some units must be pushed, while others are self-propelled, so the user only has to steer. Brush mowers are helpful for small patches of brush.

Tow-behind and walk-behind brush mowers are available in electric- or gas-powered versions. Electric-powered brush mowers have a lower noise level, lower emissions, are easier to maintain, and weigh less. Gas-powered brush mowers have more power and are better for cutting through thick vegetation. Gas-powered brush mowers are more flexibly mobile since they do not rely on a power cord or battery.

Brush Cutter

Brush cutters (also known as “weed eaters” or “clearing saws”) are handheld metal blades with multiple cutting edges or thick nylon cords attached to a spinning head. They cut thick weeds, small saplings, and light brush by chopping them as the head moves through the plants. They are easy to operate and effective on smaller woody vegetation. Unlike mowers, brush cutters cut and trim, leaving behind debris instead of mulch. 

Chainsaws

Chainsaws are available in many sizes and at various prices. They are used to fell trees, prune branches, and cut logs into smaller pieces. The chainsaw bar length should be at least two inches longer than the diameter of the vegetation being cut. Branches should be pruned following the American National Standards Institute A300 Tree Care Standards.

When using a chainsaw to fell a tree, cut the stumps to within 3–4 inches of the ground. Treating stumps with herbicide after cutting with the cut stump treatment approach described previously prevents the stump from producing sprouts.

Loppers

A type of pruning shear with long handles and fixed blades, loppers are used to cut branches or stems that are 0.5–1 inch in diameter. They are very portable and useful for pruning shrubs and trees or cutting the trunks of small groupings of trees and shrubs.

Burning

Under Iowa Administrative Code 567—23.2(455B), open burning is generally prohibited. However, the following exceptions pertaining to the disposal of woody vegetation that has been removed from roadsides may allow for the burning of cut brush.

At a municipal burn site, trees and tree trimming not originating on the premises may be burned provided that:

• the site is operated by a local government entity
• the site is fenced and access is controlled
• burning is supervised and conducted regularly
• burning is conducted when conditions are favorable to the surrounding property
• unless a written waiver is obtained, the burn site is limited to areas at least 1/4 mile from any inhabited buildings

Before burning for the first time, check with the relevant city or county department since local rules may be more prohibitive than state ordinances. Some counties require obtaining a permit before burning. When burn bans are in place, most open burning is not allowed.

Chipping

Brush that is chipped into mulch may be collected and trucked to county locations, such as a secondary road department shop yard.

Leaving Alone

Some brush may be left to provide wildlife habitat on site as it naturally deteriorates. Small mammals such as squirrels, foxes, and chipmunks may use brush piles as shelter. Songbirds may use brush piles for shelter and as a source of nesting material.

During active brush control work, equipment on the side of the road may distract drivers. Roadside managers need to plan how they will keep workers and motorists safe. Refer to the Manual on Uniform Traffic Control Devices for Streets and Highways for more detailed information on safely diverting traffic from a work area. 

The following recommendations for conducting safe roadside brush control with equipment in the roadside are excerpted from “Tree and Brush Control For County Road Right-of-Way.”

Short-Term Roadside Work With No Encroachment on the Roadway

• Workers and equipment operate within 15 feet of the edge of the traveled way for up to one hour (see below for work lasting more than one hour).
• Whenever appropriate, vehicles should be parked in entrances and driveways. If that is not possible, vehicles should be parked on the shoulder as far from open traffic lanes as possible.
• Vehicles should be equipped with a yellow revolving light or yellow strobe light.

Lengthier Work and/or Minor Encroachment of a Work Zone Onto a Two-Lane Road

• This work can occur on either gravel or paved roads.
• The work could include chainsaw work, cut stump treatment, chipper work, foliar spraying, and basal bark spraying.
• Signage is required in the opposite lane of traffic only when sight distance is restricted.
• Traffic control via flaggers is not required if bidirectional traffic can move freely through the work area at a reduced speed.

Major Encroachment and/or Lane Closure on a Gravel Road With Self-Regulating Traffic 

• The work could involve the use of aerial lift trucks, tractors with boom mowers, excavators with brush cutters, tree shears, a bucket and thumb, and other heavy equipment.
• Diagram how lanes of the road would be closed for the brush control project during daylight hours.
• Traffic volume must be less than 2,000 vehicles per day.
• Work vehicles should not be parked on the opposite shoulder within 500 feet of the work area.
• Traffic in the open lane should be allowed to flow freely.
• Cone spacing should be based on the posted speed limit.
• Traffic control via flaggers should be required if:
  • visibility is less than a quarter mile
  • workers are on the road or close enough to the road that they need to be protected from traffic 
  • traffic flow is more than 15 vehicles per 15 minutes
• When access to the truck is necessary and the side being accessed is exposed to traffic, a 2-foot safety zone is required between the cones and the truck.
• Open lanes should be at least 10 feet wide. If a lane is 9 feet wide, it may remain open for short-term use if traffic is low in speed and volume and does not include long, heavy commercial vehicles. The lane should be closed if it is less than 9 feet wide.

One Lane Closed of a Two-Lane Road for Less Than a Quarter Mile Long

• The work taking place could include extensive brush clearing, the use of excavators with brush cutters, tree shears, a bucket and thumb, and other heavy equipment.
• The work should take place during daylight hours only.
• Work vehicles should not be parked on the opposite shoulder within 500 feet of the work area.
• Cone placement guidelines:
• Space the cones 10 to 20 feet apart to create a taper that gradually narrows the amount of the road available to traffic. 
• A minimum of five cones are to be used in a taper.
• Cones that are part of a taper around a curve should be placed at the following intervals: 
  • every 20 feet where the horizontal curve radius (a measure of the bend in the road) is less than 300 feet
  • a minimum of every 50 feet where the horizontal curve radius is 300–1,000 feet
  • every 120 feet when the speed limit is 60 miles per hour or above
    • Individual cones that would interfere with the work may be omitted during work hours, except for cones in the taper, which are required at all times
• Traffic control flagger guidelines:
  • The flagger should stop the first vehicle from the position shown in Figure 8.4 and then cross traffic to the other lane to stop other vehicles.
  • Additional flaggers should be stationed at intersections or crossings within the work area to prevent vehicles from entering against the flow of traffic.
  • For a short time, the length of the work area may change as much as half a mile to improve the flagger’s sight distance. For example, the work area and flagger’s sight distance may need to be adjusted to account for changing visibility conditions due to weather or the amount of daylight.

Prescribed burns can prevent shrubs that invaded native prairie plantings from getting too big. To conduct prescribed burns, cities and counties should have staff who have completed wildland fire training (training courses S-130 and S-190). See Chapter 9: Prescribed Burning for more information. 

Roadside Real Talk

Insights from Roadside Managers and Other Professionals

Fall prescribed fire works very well for controlling small-to-medium eastern red cedar, especially if done following earlier foliar spraying to help stress the tree. 

—Lakota Kirst, Cerro Gordo County, 2024

The keys to a successful and safe prescribed burn are adequately trained staff, the right equipment, and advanced planning.

Training Requirements

Though there are no statewide minimum training requirements for individuals participating in roadside burns, the Iowa Department of Natural Resources (DNR) offers training that provides basic information about executing safe prescribed burns.

The minimum recommended training to participate in a prescribed roadside burn is the Introduction to Wildland Fire series that covers the basics of fire behavior and wildfire firefighting techniques, consisting of the following courses:

• NWCG S-130, Firefighter Training (Wildland) Q0900 - S130
• NWCG L-180, Human Factors in the Wildland Fire Service Q0902 - L180
• NWCG S-190, Introduction to Wildland Fire Behavior Q0901 - S190

These courses, totaling 40 hours, are offered online through the Wildland Fire Learning Portal, maintained by the National Wildfire Coordinating Group’s Wildland Fire Learning Portal Governance Board. An in-person field day is required to receive certification for this training. The Iowa DNR Fire Management Training website includes a calendar with upcoming in-person training days. The website also has an Iowa Annual Fireline Safety Refresher that can be completed online.

Roadside managers and other staff wanting to go beyond the introductory training to add more expertise to the crew conducting prescribed roadside burns can become certified as a Firefighter Type 2 (FFT2). This is also known as “red card” certification, in reference to the card that FFT2s receive, certifying they are qualified to work on wildland fires. For more information on becoming certified, check the Wildland Fire Learning Portal. 

Staffing Requirements

Staffing requirements for roadside burns vary with the conditions at each site; the recommended size of the crew depends on the size and complexity of the burn. As a general rule, two to four qualified people can safely execute most roadside burns. Burning alone or conducting an understaffed burn is not advised. Coordination with other agencies may be necessary if internal staffing is inadequate. Possible collaborators include secondary road maintenance crews, county conservation boards, local fire departments, and other county IRVM programs.

Minimum Suggested Personal Protective Equipment

Personal Protective Equipment (PPE) standards vary among agencies. If specific policies are not in place, the following minimum PPE is recommended:

• leather work boots
• gloves
• safety glasses
• clothing made of natural fibers

It is important to communicate information about the purpose and timing of the prescribed burn to adjacent landowners and the public. See Appendix 9A for a sample press release announcing a prescribed burn and Appendix 9B for a sample adjacent landowner notification memo. Additionally, see Appendix 9C for a sample burn site spreadsheet cataloguing controlled burns in the county, Appendix 9D for a sample prescribed burn management plan, and Appendix 8E for a sample weather data report. Typically, the local fire department will require a copy of the prescribed burn plan so it can be prepared in case the fire gets out of hand. Be aware of your local regulations regarding prescribed burns, including any requirements for a permit. 

Roadside Real Talk

Insights from Roadside Managers and Other Professionals

Burning in the ROW can be dangerous and difficult, but it is an important part of the roadside program that should be utilized. Try to minimize smoke over the road and set up work zone flagging if necessary. 
—Joe Kooiker, Story County 2024

Plan for the worst with water and equipment so you’re not underprepared. Roadside burns can be challenging, but when done correctly, they’re not a big deal. It’s an accepted management practice that’s cheaper than spraying and cutting.
—Wes Gibbs, Jones County 2024

Stick with your burn plan. Even if you’ve spent a lot of time getting equipment and personnel to a burn site, if on that day conditions in the field do not meet what was written in your burn plan, do not burn. 
—Linn Reece, Hardin County, 2011

A small test burn at the anchor point will indicate fire and smoke behavior and the feasibility of continuing with the prescribed burn. We use strip head fires to speed up the burn without using a full-blown head fire. It works well with a smaller crew. Multi-use tanks and pumping systems should be thoroughly cleaned inside and out before being used for a new purpose.
—Jon Steege, Fayette County, 2011

We try to vary burn seasons and intervals between burns so we aren’t adversely affecting any one set of desirable species.
—Jim Uthe and James Devig, 2024

Temperature

• 

  All seasons are becoming warmer (see Figure 10.5), especially spring and winter (except for February).

• There are fewer cold nights.

Precipitation

• Heavy downpours with 2–3 inches of rain or more in one event are becoming more common.
• Spring and fall are becoming wetter on average, especially in April and October.
• Rapid-onset droughts that are short in duration are becoming more common in the summer with warm conditions and reduced precipitation in July and August.
• Most of the state experiences more than 40% of its annual precipitation on the 10 wettest days of the year.

Growing Season

• The duration of the growing season has increased by 8–12 days.
• Spring frosts are occurring earlier and fall frosts are occurring later than they used to.

• Soil erosion, runoff, and flooding are becoming more common.
• Dry conditions lead to more dust from gravel roads landing on roadside vegetation, which decreases the effectiveness of herbicides
• Drier summers mean less soil moisture available to plants.
• Nitrogen deposition in the soil is 2–6 times what it was in pre-industrial times, which gives invasive species a competitive advantage
• Weeds and woody species, including eastern red cedar, are expected to expand because of warming temperatures.
• Cool-season invasive grasses like smooth brome grass are increasing, possibly because of increased rainfall early in the season.
• Increasing outdoor carbon dioxide levels help some invasives, such as poison ivy, thrive. Poison ivy also becomes more toxic because of rising carbon dioxide levels
• Tick populations are rising.
• It is unclear if the types of species that are common in prairie vegetation will change in the coming years. Plantings and remnants with many plant species are more resilient, as the variety ensures the inclusion of plant species that are adapted to different conditions.

• Consult with herbicide vendors to discuss mitigating the effects of reduced herbicide effectiveness due to dust. Mitigation strategies may vary depending on the brand of herbicide.
• Add as much plant diversity as you can afford when planting roadsides; a diverse seed mix provided for free from the Tallgrass Prairie Center includes species adapted to many types of moisture conditions, from drought-tolerant to wet.
• Seed when weather conditions are favorable (see Chapter 5: Seeding)
• It is best to seed after it has rained, not before.
• If seeding in the spring, you may need to increase the seeding rate to compensate for seed that is dislodged during heavy spring rain events.
• If possible, do more dormant seeding, when the ground is not yet frozen but cold enough that seed will not germinate until the warmer spring months, to reduce the chances of extreme weather affecting your plantings.
• Conserve water by reducing mowing during drought conditions. If feasible, mowing vegetation at a height of 10 inches or more also helps conserve water.

• Iowa Environmental Mesonet
• Iowa Climatology Bureau
• Chicago Wilderness Prairies Climate Adaptation Resource
• Fifth National Climate Assessment
• Iowa Climate Assessment (an in-depth analysis of Iowa’s past and potential future climate in the planning phase as of 2025)

Timing of Mowing

Mowing can negatively impact pollinators by reducing floral resources and host plants, which are specific plant species that a given insect species is adapted to for food, shelter, or reproduction. For example, it is well known that monarch butterflies only lay their eggs on milkweed plants, though adult monarchs will forage on many plant species. 

Mowing can also disturb or kill nesting pollinators or pollinators in early developmental stages, such as larvae and pupae that cannot escape during mowing.

Best practices for mowing that support pollinators include:

• Mowing only in clear zones, which are roadsides clear of objects, where vehicles that have left the roadway can traverse safely.
• For narrower roads with less traffic, maintain narrower clear zones compared to wider, more trafficked roads.
• Outside of clear zones, mow roadsides only very early and/or late in the growing season; summer mowing causes a lot of pollinator mortality.
• When possible, leave perennial shrubs and standing woody stems as habitat for nesting bees.

Herbicide Application

Herbicide spraying may hurt pollinators by killing or harming eggs, larvae, and adult pollinators. Sublethal effects are non-lethal effects and may include weakening of the immune system, disrupted foraging and navigation behaviors, impaired reproduction, and shortened lifespan. Spraying can also reduce the availability of floral resources and host plants that pollinators depend on.

Best herbicide application practices for supporting pollinators include:

• Use targeted spraying of weeds rather than blanket spraying to reduce the area affected by the herbicide.
• Spray early in the growing season, before plants start flowering.
• Avoid spraying when weeds or nearby plants are flowering.
• Spray on days with little wind that can cause the herbicide to drift onto desirable plants.
• Limit herbicide use altogether to address noxious weeds and other high-priority plants to remove.
• Do not spray insecticides.

Planting Native Vegetation to Attract Pollinators

Best native vegetation planting practices for attracting and supporting pollinators include:

• Do not plant in medians, which increases the risk of pollinator mortality from collisions with vehicles.
• Plant diverse mixtures of native forbs and grasses. A general recommendation is to have three forb species that bloom early in the season, three that bloom in the middle of the season, and three that bloom later in the season, so there are flowering resources throughout the season.
• Remember that a balance with roughly 50% of the mix consisting of grasses and 50% consisting of forbs (by weight of the seeds) helps pollinators. Grasses help reduce the spread of weeds within the habitat, ensure there is enough fuel for a prescribed burn, and ensure there are some host plants for caterpillar larvae that depend on grasses rather than flowers.
• For more information on flowering plants that are especially attractive to pollinators, check with a reputable native seed nursery or the additional resources listed below.

• Roadside Best Management Practices that Benefit Pollinators | FHWA handbook
• Maintaining Roadsides for Pollinators Establishment, Restoration, Management and Maintenance: A Guide for State DOT Managers and Staff
• Roadside Monarch and Pollinator Habitat: A Guide for Communities | National Wildlife Federation
• Managing Roadsides and Rights-of-Way for Pollinators | Xerces Society
• Roadside Habitat for Monarchs | Monarch Joint Venture

You may encounter residents who want to learn about planting pollinator habitat on their property. The following resources may be of interest to them.

Planning, Designing, Implementing, and Maintaining 

• Mowing to Monarchs Program | Dubuque County Conservation
• NRCS USDA Pollinator Gardens | United States Department of Agriculture
• Creating Your Own Native Garden: A Guide To Creating Beautiful Home Landscapes | Wild Ones

Sourcing Materials 

• Seed and Service Providers List and Live Plant Materials List | Tallgrass Prairie Center
• Search for local native plant sales put on by conservation groups. For example, Hartman Nature Reserve’s annual native plant sale in Black Hawk County and Golden Hills RC&D’s annual native plant sale in Pottawattamie County.

Funding

• Connect with your local Trees Forever Field Coordinator
• List of funding sources | Blank Park Zoo’s Plant.Grow.Fly conservation initiative

Books 

• Prairie Up: An Introduction to Natural Garden Design, By Benjamin Vogt
• Planting in a Post-Wild World, By Claudia West and Thomas Rainer
• The Gardener’s Guide to Prairie Plants, by Hilary Cox and Neil Diboll

Use this survey as a tool for evaluating existing roadside management practices. The results will identify strengths and weaknesses of the current approach and be a guide for shaping future roadside vegetation management practices. The survey is primarily intended to be used by an integrated roadside vegetation management steering committee. Responses can be subjective, varying widely from one person to the next. Interviewing roadside management personnel will add validity to the results.

1. Existing tree and brush control

a. Maintenance of sight lines

b. Maintenance of the recovery zone

c. Removal of trees that present immovable objects

d. Removal of hazardous tree limbs

e. The amount of tree cutting in general

f. Quality of tree and brush cutting

2. Existing weed control

a. General perception of roadside weed control

b. The amount of roadside spraying being done

c. Effectiveness of roadside weed spraying

d. Characterize the application of herbicides

e. Do spray crews need to cover more of the county each year?

f. Is most weed spraying completed during May, June, and September, when spraying is most effective?

g. When a landowner complains about roadside weeds, but the weeds in question are not considered much of a problem, do you...

3. Who does the roadside seeding?

4. When is native vegetation used in roadsides? Circle all that apply.

5. Equipment needs

(Consider working condition, current technology, appropriateness, and availability of each of the following and recommend what equipment needs to be replaced or added. Circle all that apply.)

6. Number of employees with:

Weed control as primary responsibility during spray season: ___
Brush control as secondary responsibility year-round: ___
Herbicide applicator certification: ___
Chainsaw and boom mower experience: ___
Vegetation management knowledge/background: ___
Native plant establishment/management experience: ___
Prescribed burn experience/certification: ___

7. How much is the county currently spending on:

Tree and brush control: $_____
Weed control: $_____
Seeding road projects: $_____
Erosion control measure installation: $_____
Weed commissioner salary: $_____

8. Based on your overall assessment of the current roadside vegetation management approach, which of the following would you recommend?

Hire a full-time professional roadside manager
Hire a 9-month assistant roadside manager
Hire more seasonal help
Hire better-qualified seasonal help
Free up more existing personnel for roadside management
All of the above
None of the above (because the current approach is effective)

The following position description contains typical duties and qualifications used by counties or cities in position descriptions when hiring a roadside manager. This description may serve as a template that counties or cities can modify to fit their needs. 

Note: The description is written for a county hiring a roadside manager. However, most references to “county” can be interchanged with “city” for municipalities using this template to hire a roadside manager.

Position Title: Roadside Manager/Roadside Vegetation Manager/Roadside Biologist/Roadside Vegetation Specialist

Department: County Engineer/County Conservation/Independent

Supervisor: County Engineer/Conservation Director/County Supervisors

Salary Range: $48,000–$85,000 (salary dependent on location and years of experience)

Definition

A permanent, full-time position for the general implementation of the county’s Integrated Roadside Vegetation Management (IRVM) program and duties associated with all aspects of vegetation management within county secondary road right-of-way (ROW) corridors. Primary work activities are focused on the continued maintenance and development of safe travel corridors for vehicles and the application of sound ecological principles to manage desired vegetation types along those corridors.

Optional

• Will perform related duties as required by the county engineer.
• Will work directly with parks, wildlife area, and conservation managers to assist them with routine public land and facility management goals and objectives.

Duties and Responsibilities

Required Qualifications

To perform this job successfully, an individual must be able to satisfactorily perform each essential duty. The qualifications represent the required knowledge, skills, and abilities.

Skills and Abilities

Education and Experience

Communication Abilities

Reasoning Ability

Certification and Licensure

Physical Demands

Work Environment

Other

1. Must be insurable for driving under the county insurance company policies.
2. Applicant will be subject to post-offer, pre-employment drug and physical testing.

The County is an Equal Opportunity Employer. In compliance with the Americans with Disabilities Act, the County will provide reasonable accommodations to qualified individuals with disabilities and encourages prospective employees and incumbents to discuss potential accommodations with the employer.

Prairie County Engineer
1234 Highway 1
Prairie City, Iowa, 54321
555-123-4567

FOR IMMEDIATE RELEASE

March 1, 2025
Contact: Mike Jones, Prairie County Roadside Manager
555-123-4567
irvm@prairiecounty.iowa.gov 

Iowa Mowing Law Protects Roadside Habitats

Prairie County Integrated Roadside Vegetation Management (IRVM) reminds Prairie County residents to protect roadside habitat for nesting game birds and songbirds this spring and early summer.

According to Iowa Code 314.17, mowing roadside ditches is restricted until July 15 to protect young pheasants and other ground-nesting birds until they are ready to fledge. The law, which applies to county secondary roads as well as state primary and interstate highways, also protects habitat for pollinators and other beneficial insects, including crop-pest predators.

The law includes the following exceptions that do allow for mowing prior to July 15: 

• Within 200 yards of an inhabited dwelling.

• For visibility and safety reasons.

• For access to a mailbox or for other accessibility purposes.

• Within 50 feet of a drainage tile or tile intake.

• In the right-of-way within one mile of the corporate limits of a city.

• To promote the growth of native vegetation or other long-lived and adaptable vegetation.

• To establish control of damaging insect populations, noxious weeds, and invasive plant species

• Within rest areas, weigh stations, and wayside parks.

• In agricultural demonstration or research plots that are adjacent to the right-of-way.

Prairie County’s roadsides provide a valuable refuge for wildlife. This law serves as a reminder to only mow shoulders during the critical nesting season and leave the rest of the roadside for the birds. For more information, see a brochure called Iowa’s Mowing Law for Roadsides, available at tallgrassprairiecenter.org/roadside-management-brochures.

Established in 2018, Prairie County Integrated Roadside Vegetation Management cares for roadsides along county roads using a variety of management techniques with sound ecological principles. The IRVM approach centers on planting and maintaining safe, healthy, and functional native prairie vegetation, which reduces erosion, enhances rainfall infiltration, creates habitat for pollinators, nesting birds, and other wildlife, and more. The IRVM approach also includes strategic herbicide application and mowing, and weed and brush control.

Prairie County IRVM is a division of the County Secondary Roads Department of Prairie County. For more information, visit prairiecounty.iowa.gov/IRVM.

SAMPLE

(Note: This is provided to show what is generally included in the seed request form. The form has minor changes (e.g., due dates) each year. Therefore, this form is only intended as a sample. Please do not fill out and submit this version of the form. The forms to be filled out and submitted will be emailed to roadside managers each year by the Tallgrass Prairie Center roadside program manager.)

To be picked up at the Tallgrass Prairie Center in spring/early summer 2025

An approved IRVM plan must be on file with the Iowa DOT 
in order to request seed.

Check with Tara Van Waus, Living Roadway Trust Fund coordinator, if you are unsure if your county or city has an IRVM plan. tara.vanwaus@iowadot.us 515-239-1768

Please submit the completed form to Kristine Nemec at: kristine.nemec@uni.edu or UNI Roadside Program, 2412 W. 27th St., Cedar Falls, IA 50614 no later than October 18, 2024.

County or City: _____________________________
Name:________________________________
Email address:_____________________
Phone number:___________________________
Signature:_________________________________
Date:____________________

Acres of seed requested (either 2.5 acres or in 10-acre increments, e.g. 10, 20, 30, etc. acres. Please no 5, 15, 25, 35, etc. acres). This seed is only to be used within county or city rights-of-way. All seed picked up in 2025 must be planted no later than December 31, 2026.

______ Acres of cleanout mix (around 20 native grass, forb, and sedge species)
______ Acres of diversity mix (around 35-38 native grass, forb, and sedge species)

Check all methods you will be using to plant the seed:

______ Hydroseeding
______ Hand broadcast seeding
______ Broadcast seeding with equipment that will not cause rutting
______ * Broadcast seeding with heavy equipment such as a tractor that may cause rutting
______ * Drilling

*If you are planning to drill, or use heavy equipment such as a tractor that may cause rutting more than 6 inches to broadcast seed for any of the 2025 seed that you will receive, note the requirement for ensuring cultural resources compliance. The locations for seed that will be drilled or seeded using heavy equipment between when you pick it up next spring and December 31, 2026 are also due by October 18, 2024 as described below. If you are hydroseeding, mechanically broadcast seeding using equipment that will not rut, or hand broadcast seeding all of the seed, you only need to report the number of acres of seed you would like, you do not have to report seeding locations.

Because the seed is acquired through a federal grant through the Federal Highway Administration, every year IDOT reviews the grant on behalf of FHWA to ensure it meets federal environmental and cultural regulations. Even if the roadside construction/maintenance project did not involve federal funds, the planting of the seed is subject to federal review. Through this process seeding locations need to be provided for review. Per the National Historic Preservation Act, the Iowa State Historic Preservation Officer and other consulting parties (Native American Tribes/Nations) are allowed to review and comment on these undertakings regarding the presence or treatment of historic properties. Our focus is to ensure drill seeding and equipment does not disturb burial locations. Please submit your drilling and heavy equipment locations to me in the format below and the tribes will review it. Do your best to anticipate the locations of any construction projects that you will drill or use heavy equipment on by the end of 2026, erring on the side of including a bit more than the area anticipated to be safe.

Google Earth files (.kmz) are required. For those who may be unfamiliar there is very good instruction on the internet and YouTube on how to create polygons in Google Earth. Truly, Google Earth is easy to use and really helps expedite this process.     

• create a polygon for each drill seed location, or where heavy equipment will be used (points or pins are insufficient)

• label the polygon with name of the road used on Google Earth (if there is more than one, use sequential numbering, Casper Ave 1, Casper Ave 2, etc.); 

• make each polygon slightly larger than will be needed (general rule of thumb is 100 feet in each direction)

• each county needs to complete the attached table (very basic – one table per county)

It is important to comply with this request to be good stewards of cultural resources and follow state and federal laws. Although the entire ROW is often assumed to be disturbed, there are recorded burial sites in the roadside located in various counties around the state. Archaeologists and contractors find unrecorded burial sites regularly. It is critical that you avoid unintentionally uncovering or disturbing a burial site during a road project not only for the bad publicity for the county but to avoid jeopardizing receipt of Transportation Alternatives Program funds by the Iowa IRVM program in the future. 

In the long-term, your county may benefit from having a desktop cultural resources study done by a consultant. A consultant can review records and provide the county an inventory of burial locations within and near the ROW. Certain county employees then have internal access to proactively check for burial sites before any roadside project, whereby being able to avoid these locations in the future and streamline the seeding review. Contact Brennan Dolan, IDOT cultural resources manager/archaeologist, at brennan.dolan@dot.iowa.gov or 515-239-1795 for more information on consultants who can conduct a study. There may be a cost savings for neighboring counties to join together to have a desktop study done for their counties.

2025 Cleanout Mix, 10 Acres

Group I—Grasses and Grass-Like Plants

*These are in the forb bags.
PLS = pure live seed

1 Black Bag, Blue Tie

Group II—Forbs

PLS = pure live seed

2025 Diversity Mix, 10 Acres

Group I—Grasses and Grass-Like Plants

*These are in the forb bags.
PLS = pure live seed

1 Black Bag, Grey Tie

Group II—Forbs

PLS = pure live seed

Wet Species

PLS = pure live seed

Note: The last species will grow best in a wetter habitat, a location with more soil moisture such as the ditch bottom. The 3 species labeled as having small seeds won’t grow if they get buried. One way to plant them would be to mix the seed in a bucket of sand and scatter it by hand on the soil surface towards the bottom of the ditch.

Native Plant and Seedling Guides

Books

• An Illustrated Guide to Iowa Prairie Plants by Paul Christiansen and Mark Müller (1999).
• How to Know the Grasses by Richard Pohl (1978).
• The Prairie in Seed: Identifying Seed-Bearing Prairie Plants in the Upper Midwest by Dave Williams (2016).
• Roadside Plants and Flowers by Marian Edsall (1985).
• The Tallgrass Prairie Center Guide to Seed and Seedling Identification in the Upper Midwest by Dave Williams (2010).
• Tallgrass Prairie Wildflowers: A Field Guide to Common Wildflowers and Plants of the Prairie Midwest by Douglas Ladd and Frank Oberle (1995).
• The Vascular Plants of Iowa by Lawrence Eilers and Dean Roosa (1994).
• Wildflowers of the Tallgrass Prairie: The Upper Midwest by Sylvan Runkel and Dean Roosa (2009).

Free Online Publications

• Central Region Seedling ID Guide for Native Prairie Plants by Natural Resources Conservation Service Plant Materials Program and Missouri Department of Conservation (2005).
• The Prairie Seedling and Seeding Evaluation Guide by Santec for the Iowa Department of Transportation Living Roadway Trust Fund.
• Wetland Plants and Plant Communities of Minnesota and Wisconsin by Steve Eggers and Donald Reed (2015).

Restoration and Management Guides 

Books

• A Practical Guide to Prairie Reconstruction by Carl Kurtz (2013).
• The Ecology and Management of Prairies in the Central United States by Chris Helzer (2010). 
• The Tallgrass Prairie Center Guide to Prairie Restoration in the Upper Midwest by Daryl Smith, Dave Williams, Greg Houseal, and Kirk Henderson (2010).
• The Tallgrass Restoration Handbook edited by Stephen Packard and Cornelia Mutel (2005).

Free Online Publications

• Native Seed Production Manual by the Tallgrass Prairie Center.
• Tree and Brush Control for County Road Right-of-Way by Iowa Highway Research Board—Iowa Department of Transportation and Roadside Management Program at the University of Northern Iowa (2002).

Weed and Weed Seedling Guides

Books

• Invasive Plants of the Upper Midwest: An Illustrated Guide to Their Identification and Control by Elizabeth Czarapata (2005).
• Weeds of the Midwestern United States & Central Canada edited by Charles Bryson and Michael DeFelice (2010).
• Weeds of Nebraska and the Great Plains by James Stubbendieck, Geir Friisoe, and Margaret Bolick (1995).
• Weeds of the Northern U.S. and Canada: A Guide for Identification by France Royer and Richard Dickinson (1999).

Free Online Publications

• A Field Guide to Terrestrial Invasive Plants in Wisconsin edited by Thomas Boos, Kelly Kearns, Courtney LeClair, Brendon Panke, Bryn Scriver, and Bernadette Williams (2010).
• Common Weed Seedlings of the North Central States by Andrew Chomas, James Kells, and J. Boyd Carey (2001).

According to Iowa Code Section 317.13, landowners who want to burn, mow, or spray in roadsides must obtain a work permit. The following sample work permit contains excerpted sections from permits found in county integrated roadside vegetation management (IRVM) plans. This sample permit is not meant to be comprehensive or a direct template. See the county IRVM plans on the Living Roadway Trust Fund’s IRVM website for examples of actual permits.

Prairie County Secondary Roads Department 
Permit to Perform Work Within the Right-of-Way

Date:____/____/________

Name:______________________________________________________________________

Address:____________________________________________________________________

Phone:______________________________________________________________________

Email:_______________________________________________________________________

Work site address or road name(s):______________________________________________

Section:_______________________ Township:_______________________

Other identifying information (e.g., near a landmark): _______________________________

Request details (what work do you want to do and why?): ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

1. Permits are required before any physical change can be made. 
2. Work must comply with the County's integrated roadside vegetation management regulations any all laws now in effect or that may be hereafter enacted.
3. The permittee must take all reasonable precautions during the work to protect and safeguard the lives and property of road users and adjacent property owners. The County shall be held harmless for any injuries, damages, or losses that may occur. Proper warning signs and/or devices in compliance with the Uniform Traffic Control Devices for Streets and Highways shall be used to alert road users of work being done. 
4. The permittee shall hold the County harmless for any damage to the road due to the work being done. The permittee shall reimburse the County for any costs incurred due to the permittee's work. 

Foliar Brush Control Herbicide Recommendations

Roadside manager notes (2011) — Foliar herbicide:

• Garlon/Escort is a common mix for brush control. Where Garlon (triclopyr) is noted, either Garlon 3A (amine formulation) or Garlon 4 (ester) can be used. Garlon 4 is usually more effective but in hot weather can volatilize drift and affect non-target species. 3A is non-volatile and usually considered the best choice for hot weather. 
• We quit spraying Tordon in roadside situations due to standing water and high water tables.
• Arsenal usually kills cool season grass, which can eventually create thistle problems. We limit its use to Japanese Knotweed.
• We've had good luck with Opensight at 3.3 ounces per acre plus an additional 1 ounce per acre of Escort on all of these trees.
• Honeysuckle control is different. When isolated patches are found, consider basal treatment.

Basal Bark Brush Control Herbicide Recommendations

Roadside Manager Notes (2011) — Basal Bark Herbicide:

• We've started adding about 0.5–1% Stalker to our 25% Garlon 4 mix. We used to add 3% Stalker, but our "ring of death" seemed to last for three or more years rather than just one.
• It helps to hack up thick- or corky-barked tress and trees > 2 inches in diameter.
• For most trees, we use 2.5 gallons Garlon plus 4 quarts Stalker plus 12.5 gallons diesel fuel or basal oil to make about a 15 gallon mix.

2002 herbicide recommendations taken from Tree and Brush Control for County Road Right-of-Way.

Some landowners prefer that herbicides are not used to manage weeds in the roadsides that border their property. The following sample no-spray request form contains excerpted sections from similar forms found in county integrated roadside vegetation management (IRVM) plans. This sample permit is not meant to be comprehensive or a direct template. See the county IRVM plans on the Living Roadway Trust Fund’s IRVM website for examples of actual forms.

Prairie County Secondary Roads Department
No-Spray Request Form

I, __________________________, hereby request that the Prairie County Integrated Roadside Vegetation Management (IRVM) department, within the Secondary Roads Department, refrain from applying pesticides in the right-of-way adjacent to my property, located at the address of _______________________________________, on the ________ side of the road in Section_______ of ________________________Township along ___________________ road. In return, I agree that I am responsible for the vegetation management of the above-described portion of the right-of-way, including the destruction of noxious weeds and the prevention of new growth or regrowth of trees and brush. This request is valid for one growing season.

I understand that other parties (e.g., electric, gas, phone companies) may apply pesticides and herbicides and cut trees and brush within the right-of-way.

I acknowledge that if I fail to properly manage the right-of-way by non-chemical means, Prairie County reserves the right to spray the area, at which time the agreement becomes null and void and the right-of-way is returned to the IRVM for management. 

I understand that it is my responsibility to post and maintain “No Spray” signs provided by Prairie County Conservation at a rate of $____ per set. Signs must remain visible from the roadway. If they are not visible or properly maintained, the agreement becomes null and void.

Approval is ▢ given ▢ not given from date below to the end of the current calendar year. It is the applicant’s responsibility to submit a renewed application by January 1, ________.

Iowa Pesticide Applicator Licenses and Certifications 

Certified Applicators 

Each individual who applies pesticides for a state or county agency, municipal corporation or other government entity is required to be certified. Certified public applicators may obtain a one-year certification for $10 or a three-year certification for $15. Certifications are valid only when associated with a valid licensed agency. Written examinations are required for first-time applicators. Written exams are also required for individuals adding on certification categories and those persons choosing not to maintain continuing instruction credit hours.

The core examination and appropriate category test(s) must be successfully passed before application for certification can be made. Additional categories may be added anytime with no extra charge. Any category will carry the same expiration date as the card on which it is added. Each certified individual must be listed as an applicator under a current Iowa pesticide applicator license for that certification to be valid. 

Renewal of Applicator Certifications 

Each applicator is placed on a three-year “qualification cycle.” During those three years, an applicator may maintain a single-year certification by submitting a one-year fee and renewal form (certification renewal forms are provided by the Pesticide Bureau). A 30-day grace period from the date of expiration will be allowed for the renewal of the certification. At the end of the qualification cycle each applicator must indicate a method of renewal by: 

1. Declaring that at least two hours of continuing instruction for each certified application category has been received for each of the previous three years and verification of having received training is on file with the applicator’s employer; or, 
2. Completing written tests at the end of the third year of the “qualification cycle;” or, 
3. Maintaining a combination of training and testing. 

Note: An applicator who misses two hours of training for any one category for any one year is required to complete written tests for that particular category. There are no provisions for “making up” missed continuing instruction hours to avoid the written test. 

Written applicator tests are offered daily, Monday through Friday from 9 a.m. to 3 p.m. at the Wallace Building at East Ninth and Grand in Des Moines. If a group of ten or more is involved, please call (515) 281-4339 or (515) 286-5601 and make an appointment. Otherwise, no appointment is necessary. Photo identification is required. Tests are also offered on a limited basis at some cooperative extension service area offices. Please contact either the area office or the Pesticide Bureau for a current testing schedule.

Contact Information 

Restricted-Use Pesticide Recordkeeping 

These rules apply to both certified private and commercial applicators. The Iowa Pesticide Act requires applicators to keep records of all pesticide applications for 3 years. The federal regulations require pesticide applicators to record the following information within 14 days of the restricted use pesticide application: 

• The brand or product name and the EPA registration number of the restricted use pesticide that was applied. 
• The total amount of the restricted-use pesticide applied. 
• The location of the application. 
• The size of the area treated. 
• The crop, commodity, stored product or site to which the pesticide was applied. 
• The month, day and year on which the restricted-use pesticide application occurred. 
• The name and certification number of the certified applicator who applied the restricted-use pesticide.

More information can found in this IDALS document. 

Controlling brush in roadsides enhances driver safety and is a key component of any Integrated Roadside Vegetation Management (IRVM) plan. The following excerpts from IRVM city and county plans across Iowa serve as examples of policies in place used to manage roadside brush.

Removal of a public tree shall be complete, and the work site shall be cleaned up promptly and all tree trunks, limbs, branches, twigs and brush shall be disposed of in an authorized manner.
—City of Davenport Procedure for Tree Removal section

As stated in the previous section about chemicals, the goal is to utilize native forbs, grasses, and sedges to compete with weeds and woody species to reduce the amount of pesticide needed in the future.
—Polk County Tree and Brush Control section

A systematic approach will be needed to control brush…the control of brush from the fore slope to ditch bottom should be managed countywide. As time and resources allow, additional areas of the ROW can be controlled for brush.
—Bremer County Noxious Weed and Brush Control section

Brush control represents the major thrust of mechanical or "hands-on" implementation for Des Moines County's Roadside Vegetation Management program. Small brush will be controlled using spot-treatment techniques designed not to disturb beneficial plant communities.
—Des Moines County Brush Control Plan section

Tree and brush control (non-herbicidal) is conducted on all portions of the right-of-way in IRVM seedings as time and resources allow.
—Guthrie County Tree and Brush Control section

The number one concern for a brush removal policy is safety for the traveling and general public... There are certain conditions within the Right of Way in which brush or trees present clear hazards. In these situations, the brush and trees which are in close proximity to the road surface must be removed. Trees within the Right of Way, but greater than 30 feet from the road surface present reduced hazard and may be considered individually.
—Johnson County Brush Control Policy

Webster County currently has a contractor hired to spray brush by a foliar application on a four-year rotation. The county is divided up into 4 horizontal tiers in which one tier is sprayed each year. The Secondary Road Department works two tiers ahead of the contractor cutting down larger brush and trees. When the contractor arrives at that site two years later the re-growth is the proper size to receive a foliar application.
—Webster County Brush/Tree Control section

Prairie County Engineer
1234 Highway 1
Prairie City, Iowa, 54321
555-123-4567

FOR IMMEDIATE RELEASE
March 1, 2025
Contact: Mike Jones, Prairie County Roadside Manager
555-123-4567
irvm@prairiecounty.iowa.gov

Prescribed Burning in County Roadsides

Prairie County Integrated Roadside Vegetation Management (IRVM) will be conducting prescribed burns in roadsides adjacent to county roads during the next few months. Prescribed burns are an effective resource management tool utilized to discourage the growth of weeds and woody vegetation, while promoting the growth of desired native prairie vegetation in roadsides. All staff members working on prescribed burns are certified in wildland firefighting and take all necessary safety precautions to minimize the risks associated with a prescribed fire. Please use caution when approaching a burn site, as staff members and equipment may be near the road.

Established in 2018, Prairie County Integrated Roadside Vegetation Management cares for roadsides along county roads using a variety of management techniques with sound ecological principles. The IRVM approach centers on planting and maintaining safe, healthy, and functional native prairie vegetation, which reduces erosion, enhances rainfall infiltration, creates habitat for pollinators, nesting birds, and other wildlife, and more. The IRVM approach also includes strategic herbicide application and mowing, and weed and brush control.

Prairie County IRVM is a division of the County Secondary Roads Department of Prairie County. For more information, visit prairiecounty.iowa.gov/IRVM.

P R A I R I E  C O U N T Y  E N G I N E E R
1 2 3 4  H I G H W A Y  1
P R A I R I E  C I T Y ,  I O W A  5 4 3 2 1
5 5 5 - 1 2 3 - 4 5 6 7

MEMO

TO: Joan Q. Public
FROM: Mike Jones, Prairie County Roadside Manager
DATE: MARCH 10, 2025
RE: Controlled burning in the roadside

Joan Q. Public
4321 Apple Avenue
Prairie City, IA 54321

 A prescribed burn for the roadside in the vicinity of your residence is scheduled to be conducted this spring by Prairie County Integrated Roadside Vegetation Management. The burn will be conducted by adequately trained personnel and only under the safest conditions. The purpose of this memo is to notify you that:

1. A prescribed burn will occur in the roadside on Apple Avenue between 120th Avenue and 130th Avenue.
2. Smoke will be produced in and around the vicinity of the burn for a short time.
3. This action may require minor traffic control around your residence.

Why Prescribed Burning?

In order to encourage the establishment of native plants in our county roadsides, Prairie County Integrated Roadside Vegetation Management uses various management techniques with sound ecological principles. Prescribed burning (not to be confused with wildfire) is any fire ignited by management actions to meet specific objectives. Goals of prescribed burns in terms of roadside management include stimulating the growth of desirable species such as native grasses and flowers, impeding the growth of undesirable species such as weeds and woody vegetation, and giving desirable species a competitive advantage over undesirable species. In some instances, a prescribed burn may replace the need to use herbicides in the roadside. 

For any questions, comments, or concerns about this notice, please contact:

Mike Jones, Roadside Manager/Weed Commissioner
Prairie County Integrated Roadside Vegetation Management
Prairie County Secondary Roads Department
1234 Hwy 1
Prairie City, IA 54321 
555-123-4567
irvm@prairiecounty.iowa.gov 

Burn History

Last updated: 5/1/2025

Location: west side of Apple Ave. between 120th St. and 130th St.

Date: April 18, 2025

Prescribed Burn Parameter for This Location

Temperature: 40–70°F

Wind direction(s): East or southeast

Wind speed: <15 miles per hour

Relative humidity: >30%

Personnel requirements: 1 crew boss, 1 additional

Equipment requirements: 1 pump truck (300 gallons), hand tools, 1 backpack sprayer

Potential hazards:

• Wood utility poles (x6)
• Phone box 20 yards north of farm drive
• Corn stubble in adjacent field (tilled)
• Stop sign
• Plastic culvert under farm drive

Prepared Fire Breaks Required

Description:

• Wet line near the intersection of Apple Ave. and 120th St.
• Wet lines around potential hazards

Potential anchor points: Northwest or southwest corners

Special concerns:

• Heavy traffic on Apple Ave. after 3 p.m.
• Acreages/farms located to the west and northwest

Notes:

Smooth brome is abundant on the north end–early spring burn is desired

Emergency Phone: Conservation Board office, 555-111-5678

Local Fire District: Prairie City Fire Department, 555-111-8765

Location: west side of Apple Ave. between 120th St. and 130th St.

Date: April 18, 2025

Personnel:

• Crew boss: Mike Jones
• Crew: James Smith

Forecasted Weather Data

Source: NOAA

Forecast time frame: 9–11 a.m.

Temperature: 60–68°F

Relative humidity: 55–62%

Relative humidity: 58%

Dew point: 32°F

Wind direction: southeast

Wind speed: 7–10 mph

Cloud cover: partly cloudy

Beginning On-Site Weather Data

Time: 9:35 a.m.

Temperature: 64°F

Dewpoint: 32°F

Wind direction: east-south-east

Wind speed: 8–10 mph

Cloud cover: Mostly sunny

Ending On-Site Weather Data

Time: 10:15 a.m.

Temperature: 66°F

Relative humidity: 53%

Dewpoint: 30°F

Wind direction: southeast

Wind speed: 8–10 mph

Cloud cover: Partly cloudy

Notes: 90% burn–approximately 2 acres