Lycopus americanus Muhl. ex W.P.C. Barton 

Alternate Common Names: American bugleweed, cut-leaved bugleweed

Scientific Synonyms: Lycopus americanus Muhl. ex W.P.C. Barton var. longii Benner, Lycopus americanus Muhl. ex W.P.C. Barton var. scabrifolius Fernald, Lycopus sinuatus Elliott

Family: ‌Mint family (Lamiaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial with sprawling stems when not supported by neighboring plants, spreading by rhizomes to form loose to dense colonies.

Height: 1 - 2.5 ft  

Leaves and stem

Leaves opposite, larger and more deeply lobed near the base of the plant, nearly hairless, no minty scent when crushed, often turning purplish red in fall; stem four-angled, grooved, and mostly hairless, typically unbranched or with few branches.

Flower, fruit and seedhead

Flower: Small (1/8 in) white flowers in dense clusters at leaf axils, calyx (sepals) fused into a tube with 5 triangular lobes; flower clusters bloom from the bottom to the top of the plant over the long flowering period.

Fruit/seed head: Four nutlets form in each calyx tube; nutlets are shorter than the calyx lobe, helping to distinguish this species from northern bugleweed (L. uniflorus).

Pollination: Small bees, wasps, flies, and other insects.

Seed

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 155,000 (Prairie Moon Nursery)

1000 seed weight: 0.14 g (Seed Information Database)

Description: Seed unit is a wedge-shaped, medium-brown nutlet, about 1 mm long, with clear beads of resin on one surface. Markings in the seed photo show millimeters.

Typical seed test 

PLS: 73.8% (n=4)

Purity: 81.5% (n=4)

Germination: 2% (n=2)

Dormancy: 40% (n=2)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Moist to wet soils, full sun to partial shade; disturbed to high quality wet prairies, fens, marshes, shores, ditches; Wetland Indicator Status is OBL (obligate, almost always found in wetlands); irrigation is needed for seed production.

Conservation status: Global- G5 (secure); Colorado- S3 (vulnerable); North Carolina, South Carolina- S2 (imperiled); Alaska, Georgia- S1 (critically imperiled); in all other states, status is S4 (apparently secure) to S5 (secure) or unranked. 

General Comments

American water horehound is not a particularly showy plant, but its long flowering time provides nectar and pollen resources for small bees, wasps, flies, and other pollinators for much of the summer into early fall. This species is found in both high quality and more disturbed remnant habitats in our region. While collecting this species for development of Iowa Source Identified stock seed, we found American water horehound in nearly every remnant wet prairie, sedge meadow, fen, or marsh we visited. This species even persists in some sites that are now dominated by cattails and reed canary grass. This species grows quickly from plugs in irrigated production rows and is productive in the establishment year. The vegetative spread of the plants produces a dense, leafy canopy that excludes many weeds, and harvesting and cleaning the seed is uncomplicated.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience with direct seeding this species for seed production.

 

‌‌Greenhouse

Seed pre-treatment: 60 days cold/moist stratification.

Sowing: Surface sow in greenhouse about 2 months before last frost. Use caution when watering to avoid splashing out small seeds. Most seeds will germinate within two weeks of sowing and grow vigorously.

Transplanting: When plugs are well rooted, move them outside to harden off, then transplant into irrigated rows with plastic mulch at 8-12 in spacing.

‌Appendix A

Stand management

Weeds: Prepare a clean, weed-free bed. Plastic mulch suppresses weeds in the first growing season but should then be removed to allow vegetative spread of plants. Plants grow densely and exclude many weeds. Mow or cultivate between rows. Hand rogue small seeded weeds that could contaminate the seed.

Pests: None noted.

Diseases: None noted.

Seed production

First Harvest: Plants grow rapidly, flower and set seed in their first growing season from transplants.

Yield: 480 - 600 pounds/acre (extrapolated from harvests of one plot)

Stand Life: The first year’s harvest may be the highest yielding. We observed slightly lower yields in the second year and will continue to track yields for another year or two.

Flowering Date: late June - early Sept 

Seed maturity/Harvest date: mid to late October

Seed retention: low risk of shattering

Harvest date range at TPC (2024-2025): Oct 20 - Oct 21

Recommended Harvest Method: combine (may need fairly high threshing speed) 

Appendix B

Seed cleaning and storage

Cleaning process: Pass combined material through 1/2 in and 1/4 in mesh to remove larger debris, then airscreen 2-3 times.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone NI (aligned with the Generalized Provisional Seed Zones of the US Forest Service)

References

Bower, Andrew D.; St.Clair, J. Bradley; Erickson, Vicky. 2014. Generalized provisional seed zones for native plants. Ecological Applications. 24(5): 913-919.

Chayka, K. (n.d.). Lycopus americanus (American water horehound). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/american-water-horehound 

Hilty, J. (2019). American bugleweed - Lycopus americanus. Illinois Wildflowers. https://www.illinoiswildflowers.info/wetland/plants/am_bugleweed.htm  

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: December 18, 2025).

Prairie Moon Nursery. (n.d.). Lycopus americanus. https://www.prairiemoon.com/lycopus-americanus-water-horehound 

Society for Ecological Restoration, International Network for Seed Based Restoration and Royal Botanic Gardens Kew. (2023) Seed Information Database (SID). Available from: https://ser-sid.org/ (February 2023)

USDA NRCS National Plant Data Team. (n.d.). Lycopus americanus Muhl. ex W.P.C. Barton. USDA plants database. https://plants.usda.gov/plant-profile/LYAM

Species Guide Updated 12/19/2025

Anemone canadensis L. 

Alternate Common Names: meadow anemone, Canada anemone, roundleaf thimbleweed, crowfoot, round-leaved anemone

Scientific Synonyms: Anemonidium canadense (L.) Á. Löve & D. Löve, Anemone dichotoma var. canadensis (L.) C. MacMillan

Family: ‌buttercup family (Ranunculaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial, rhizomatous, forms colonies.

Height: 1-2 ft  

Leaves and stem

Leaves basal with long (6 in) stalks, roughly round in outline with 3-5 deep lobes, irregularly toothed margins, and flattened hairs; flowering stem is stiff and hairy and bears a whorl of three stalkless leaves.

Flower, fruit and seedhead

Flower: Large white flowers, 5-parted, with numerous yellow stamens and a green center, up to 1 1/2 in wide, borne singly or in loose clusters of up to 3 flowers at tops of stalks.

Fruit/seedhead: Seed head mace-like, globular, containing numerous beaked achenes, often overtopped by foliage at maturity.

Pollination: Small bees and flies.

Seed

Appendix D

‌Seed characteristics 

Seed weight:

Seeds per ounce: 8,000 (IA NRCS)

Seeds per pound: 128,000 (IA NRCS)

1000 seed weight: 2.89 g (Seed Information Database)

Description: ‘Seeds’ are actually one-seeded flattened fruits (achenes), about 1/8 in diameter, arranged in a ball-shape about 3/8 in diameter.

Typical seed test 

PLS: 88% (n = 11)

Purity: 96% (n = 11)

Germination: 2% (n = 6)

Dormant: 91% (n = 6)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Mesic to wet-mesic soil; partial to full sun; moist prairies, sedge meadows, openings in floodplain woodlands, woodland borders, banks of streams, swampy areas; Wetland Indicator Status is Facultative Wetland (FACW) for the Midwest.

Conservation status: Global- G5, secure; Kentucky and Tennessee- SX, presumably extirpated; District of Columbia, Maryland, and Virginia- SH, possibly extirpated; New Jersey and West Virginia- S1, critically imperiled; Connecticut and Wyoming- S2, imperiled; Kansas- S3, vulnerable (NatureServe) 

General Comments

Canada anemone blooms early in the growing season, making it an important option for inclusion in pollinator habitat seed mixes. Remnant populations of this species persist along rural roads in Iowa, suggesting that it could be a long-lasting addition to roadside plantings, once established. Its low growth form, adaptability, and spreading habit may also be suitable for novel planting situations such as beneath solar panels. This species is challenging to propagate from seed because of its deep dormancy and difficulties with germination, but once established it tends to spread prolifically and is relatively easy to manage, harvest, and clean. Canada anemone may also be propagated by division of the rhizomes, but more than one genetic clone is needed for seed production.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Row spacing: 30-36 in rows

Seeding rate: 4.5 PLS pounds/acre (40 seeds/linear foot)

Seeding method: Native seed drill.

Seeding time: Dormant season

Weed control: Prepare clean, firm, weed free seedbed prior to seeding.

 

‌‌Greenhouse

Seed pre-treatment: Moist stratify 12 weeks at 40° F, or alternatively in ambient winter conditions (unheated building).

Sowing: Sow seed in greenhouse two months before last frost free date.  Typically this species exhibits very high dormancy (low germination) and may require two winter cycles to germinate.

Transplanting: Transplant into bare soil in rows or weed barrier at 8 in intervals after all danger of frost is past. Once plants are established they spread prolifically by rhizomes, so the weed barrier will need to be removed or slit open to accommodate growth and enhance seed production.

‌Appendix A

Stand management

Weeds: Post-emergent grass herbicide, tillage, hand roguing. Weed control is critical to successful establishment and seed production of this species. Read and follow label instructions.

Pests: Blister beetles may forage voraciously on foliage.

Diseases: None noted.

Seed production

First harvest: Some flowering and seed set at the end of first growing season from greenhouse grown transplants. Direct seeded stands may take 3 years to become productive.

Yield: 18-306 pounds/acre (yields extrapolated based on production from 3 plots)

Stand life: Peak harvests occurred in the years 3-5 after transplanting. Stands at TPC have persisted for 20 years without management, but harvests made from one plot in years 7 and 12 were much smaller than peak yields. 

Flowering date: mid-May - late June.

Seed maturity/Harvest date: mid - late July

Seed retention: Shattering occurs soon after (and perhaps before) seed maturity.

Harvest date range at TPC (2003-2015): July 15 - July 29

Recommended harvest method: Combine near maturity, but before seed head breaks apart. 

Appendix B

Seed cleaning and storage

Cleaning process: Pre-clean air-dried material by scalping thru 1/2  in and 1/4  in mesh to remove large particles. Air-screen to clean.

Seed storage: Stores well in refrigerated conditions (32-40° F, 40-60% RH).

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zones 1, 2, 3

References

Chayka, K. (n.d.). Anemone canadensis (Canada anemone). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/canada-anemone

Dutton, B. E., Keener, C. S., & Ford, B. A. (2020, November 5). Anemone canadensis Linnaeus. Flora of North America. https://floranorthamerica.org/Anemone_canadensis  

Hilty, J. (2019). Meadow anemone - Anemone canadensis. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/mdw_anemone.html

Houseal, G. A. (2007). Forbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 26–27). Tallgrass Prairie Center - University of Northern Iowa. 

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

Runkel, S. T., & Roosa, D. M. (2009). Canada anemone. In Wildflowers of the tallgrass prairie: The upper Midwest (2nd ed., pp. 54–55). University of Iowa Press.

Society for Ecological Restoration, International Network for Seed Based Restoration and Royal Botanic Gardens Kew. (2023) Seed Information Database (SID). Available from: https://ser-sid.org/ (February 2023)

USDA NRCS National Plant Data Team. (n.d.). Anemone canadensis L.. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=ANCA8

Species Guide Updated 12/1/2025

Symphyotrichum novae-angliae (L.) Nelson 

Alternate Common Names: New England American-aster, purple meadow aster

Scientific Synonyms: Aster novae-angliae L., Lasallea novae-angliae (L.) Semple & L. Brouillet, Virgulus novae-angliae (L.) Reveal & Keener

Family: ‌aster family (Asteraceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial from short thick rhizomes.

Height: 3-4 ft  

Leaves and stem

Leaves alternate with leaf bases clasping the stem, softly hairy on the underside, closely spaced and persistent near the top of the plant; stem is hairy, reddish brown in color, mostly unbranched except within the inflorescence.

Flower, fruit and seedhead

Flower: Composite flowerheads 1 to 1 1/2 in across with purple rays (occasionally pink or white) and yellow disk flowers, with long, spreading bracts (phyllaries) on the underside of each head. A single stem may bear 30-50 flowerheads in a panicle-like cluster.

Fruit/seedhead: Small hairy “seed” (achene) with a tuft (pappus) of light brown hairs. Seeds are wind-dispersed fairly soon after the pappus expands.

Pollination: Insects, primarily bees, flower flies, and butterflies.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 66,000 (IA NRCS)

1000 seed weight: 0.66 g (Seed Information Database)

Description: ‘Seeds’ are fruits 1/16 in long (achenes), with hairs attached to all parts of the seed coat.

Typical seed test 

PLS: 86% (n = 10)

Purity: 92% (n = 10)

Germination: 37% (n = 9)

Dormant: 45% (n = 9)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Wet-mesic soil conditions, prairie swales, wet meadows, full sun; Wetland Indicator Status is Facultative Wetland (FACW) for the Midwest. Avoid poorly drained clay soils for seed production purposes.

Conservation status: Global- G5, secure; Oklahoma- SH, possibly extirpated; Georgia, South Carolina, and Wyoming- S1, critically imperiled; Colorado- S2, imperiled; Kansas and North Carolina- S3, vulnerable (NatureServe) 

General Comments

This species is easy to propagate in the greenhouse. Though this species establishes readily in prairie reconstructions, weedy competition will severely curtail establishment and seed yield for seed production purposes. Fine hairs arise from nearly the entire surface of the seed, requiring thorough brushing/debearding to remove for good airscreen separation.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Not recommended for this species

 

‌‌Greenhouse

Seed pre-treatment: Wet stratify 8 weeks at 40° F. 

Sowing: Sow seed in the greenhouse 2 months before the last frost-free date.

Transplanting: Harden-off, transplant into bare soil in rows or weed barrier at 8-12 in intervals after all danger of frost.

‌Appendix A

Stand management

Weeds: Post emergence grass herbicide, tillage, hand roguing. Weed pressure severely curtails establishment and seed production of this species.

Pests: Rabbits and other mammalian herbivores seem to favor eating foliage of this and other aster species and will keep plants pruned to 8 in throughout the growing season, particularly in the establishment year.

Diseases: Powdery mildew.

Seed production

First harvest: Flowering and seed set at the end of first growing season from greenhouse grown transplants.

Yield: 20-40 bulk pounds/acre (per acre yield extrapolated based on harvests from 2 plots)

Stand life: Peak harvests 1st and 2nd year. Seed production declines significantly 3rd year and after. For ornamental purposes, plants of this species are commonly pinched back through mid-summer to increase bushiness and flowering. Whether this would also increase seed production has not been demonstrated.

Flowering date: Late August - September in northern Iowa

Seed maturity/Harvest date: Mid-September - October in northern Iowa

Seed retention: Seeds are wind dispersed very soon after maturity.

Harvest date range at TPC (2004-2009): Oct 6-25

Recommended harvest method: Combine after seed maturity but before more than 10% of the seed heads have turned brown and fluffy. Otherwise, combining will simply contribute to dispersal of the seed crop. Harvested material will have to be forced-air dried and turned carefully to prevent mold and decay. 

Appendix B

Seed cleaning and storage

Cleaning process: Pre-clean air-dried material by scalping through 1/2 in and 1/4 in mesh to remove large particles. Remove plumes with a debearder or brush machine, then air-screen.

Seed storage: cool/dry (32-40 F, 40-60% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Project Central Iowa Germplasm (IA Zone 2), Northern Iowa Germplasm (IA Zone 1), Southern Iowa Germplasm (IA Zone 3)

Cultivated variety (cultivars): Horticultural varieties also exist.

References

Chayka, K. (n.d.). Symphyotrichum novae-angliae (New England aster). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/new-england-aster 

Hilty, J. (2019). New England aster - Symphyotrichum novae-angliae. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/ne_asterx.htm 

Houseal, G. A. (2007). Forbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 52–53). Tallgrass Prairie Center - University of Northern Iowa.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

USDA NRCS National Plant Data Team. (n.d.). Symphyotrichum novae-angliae (L.) G.L. Nesom. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=SYNO2

Species Guide Updated 12/10/2025

Coreopsis palmata Nutt.

Alternate Common Names: stiff coreopsis, prairie coreopsis, prairie tickseed, finger tickseed, tickseed

Family: ‌aster or sunflower family (Asteraceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial, fibrous-rooted and rhizomatous, spreads vegetatively to form clonal colonies.

Height: 1-3 ft  

‌

Leaves and stem

Leaves opposite, sessile on the stem, deeply divided into 3 finger-like lobes; stem is rigid and grooved, mostly hairless except at the nodes, dark green in color, leafy, typically unbranched.

Flower, fruit and seedhead

Flower: Yellow composite flower heads 1-2 in across with yellow centers that turn brown as they mature, ringed by 8-12 notched “petals” (ray florets); one to a few flower heads per stalk.

Fruit/seedhead: Center disk of head turns dark brown-black at maturity; only marginal flowers produce “seeds” (achenes).

Pollination: Insects such as bees, moths, butterflies, flies, and beetles.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 10,000 (IA NRCS)

Seeds per pound: 160,000 (IA NRCS)

1000 seed weight: 2.13 g (Seed Information Database)

Description: Seed units are oblong, flattened, inwardly curved achenes with winged margins, 1/4 in (5 mm) long.

Typical seed test 

PLS: 64% (n = 11)

Purity: 70% (n = 11)

Germination: 41% (n = 10)

Dormant: 51% (n = 10)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Mesic to dry-mesic soil; full sun; medium to high quality prairie and savannas. For seed production, avoid wet or poorly drained soils.

Conservation status: Global- G5, secure; Louisiana and Michigan- S2, imperiled; Nebraska- S1/S3, critically imperiled to vulnerable; South Dakota- S3, vulnerable (NatureServe) 

General Comments

Stiff tickseed typically occurs in colonies (clonal) in native prairies, spreading from rhizomes. This species supports numerous species of pollinators, including a specialist bee (Melissodes coreopsis), and herbivorous insects. Flattened, inwardly curved, winged achenes make air-screen separation of “seed” from inert plant parts difficult and this is reflected in the average purity reported from seed tests.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Row spacing: 30-36 in rows

PLS pounds/acre: 3.0

Seeds per linear foot: 40

Seeding depth: 1/4 in

Seeding method: native seed drill

Seeding time: dormant season

Weed control: Prepare clean, firm, weed free seedbed prior to seeding.

 

‌‌Greenhouse

Seed pre-treatment: Wet stratify 8-12 weeks at 40° F.

Sowing: Sow seed in greenhouse at 1/4 in depth two months before last frost free date.

Transplanting: Harden off, transplant into prepared rows after all danger of frost. Permanent weed barrier is NOT recommended since this species spreads vegetatively, however, a biodegradable barrier can help reduce weed pressure during the first year. If planted into non-biodegradable plastic, holes must be opened further or plastic removed entirely in subsequent years.

‌Appendix A

Stand management

Weeds: Weed barrier in first year can suppress many weeds. Mow or cultivate between rows. Consider post emergence grass herbicide and roguing to prevent weed seed from contaminating seed lots.

Pests: None noted.

Diseases: Crown root rot if planted in too wet soils.

Seed production

First harvest: Some flowering in the first growing season from transplants, but minimal seed production. Flowering and seed production increases in the second year.

Yield: 10-80 bulk pounds/acre (per acre yields extrapolated based on production from 4 plots)

Stand Life: Peak harvest appears to occur in the second to third year. Stand persists but seed production may decline or fluctuate in later years. Aerating the soil of the plot post-harvest with a turf aerator may enhance seed set the following season.

Flowering date: June - mid-July in northern Iowa

Seed maturity/Harvest date: October in northern Iowa

Seed retention: Relatively low risk; shattering occurs late October to early November

Harvest date range at TPC (2003-2021): Sept 11 - Nov 6

Recommended harvest method: Combine 

Appendix B

Seed cleaning and storage

Cleaning process: Pre-clean combined material by scalping through 1/2 in and 1/4 in mesh to remove large plant matter and brush (stiff bristles) to make flowable, then air-screen repeatedly, and indent if needed to remove small seeded weeds. Because seeds are flat, separation from leaf particles of similar size and weight requires repeated air-screen cleaning to improve purity. (No awns or appendages to remove.)

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Project Zones 1, 2, and 3, Northern Missouri Germplasm, Western Missouri Germplasm

References

Chayka, K. (n.d.). Coreopsis palmata (prairie coreopsis). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/prairie-coreopsis

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Prairie tickseed. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 73). University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). Praire coreopsis - Coreopsis palmata. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/pr_coreopsisx.htm  

Houseal, G. A. (2007). Forbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 30–31). Tallgrass Prairie Center - University of Northern Iowa.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

Runkel, S. T., & Roosa, D. M. (2009). Prairie coreopsis. In Wildflowers of the tallgrass prairie: The upper Midwest (2nd ed., pp. 124–125). University of Iowa Press.

USDA NRCS National Plant Data Team. (n.d.). Coreopsis palmata Nutt. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=COPA10

Species Guide Updated 12/2/2024

Pycnanthemum virginianum (L.) T. Dur. & B.D. Jacks. Ex B.L. Rob. & Fernald 

Alternate Common Names: common mountain mint, mountain mint, basil, mountain thyme, pennyroyal, prairie hysop

Scientific Synonyms: Koellia virginiana (L.) MacMill

Family: ‌mint family (Lamiaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial with short, slender rhizomes that forms vegetative colonies.

Height: 1-3 ft  

Leaves and stem

Leaves at least 3/16 in wide or more with a strong mint odor when crushed; stem is four-sided and smooth except for short hairs on the stem angles, often branched.

Flower, fruit and seedhead

Flower: Small (1/8 in long) white, two-lipped flowers with light purple spots in tight clusters at branch tips, with many heads forming a flat-topped arrangement.

Fruit/seedhead: Mature seed heads are gray; four one-seeded nutlets develop inside each calyx tube.

Pollination: Insects such as bees, flies, wasps, and butterflies

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 220,000 (IA NRCS)

1000 seed weight: 0.14 g (Seed Information Database)

Description: ‘Seeds’ are nutlets, developing in a tube-like calyx of inflorescence.

Typical seed test 

PLS: 87% (n = 11)

Purity: 93% (n = 11)

Germination: 48% (n = 8)

Dormant: 21% (n = 8)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Wet-mesic to mesic soils; low prairies; full sun; moist well-drained loamy soils preferred for seed production; moist sand prairies or meadows, swamps, thickets, rocky bluffs, fens; Wetland Indicator Status is Facultative Wetland (FACW) for the Midwest.

Conservation status: Global- G5, secure; District of Columbia- SH, possibly extirpated; Alabama, Kansas, New Hampshire, and North Carolina- S1, critically imperiled; Arkansas- S1/S2, critically imperiled to imperiled; Georgia and Maryland- S2, imperiled; North Dakota- S3, vulnerable (NatureServe) 

General Comments

This species is typically encountered (and noticed due to its minty smell when crushed) in patches or colonies in native prairie, spreading by rhizomes. Its gray seedheads and hairs on the stem angles help distinguish this species from narrowleaf mountainmint (P. tenuifolia). The small but abundant and long-lasting flowers of Virginia mountainmint attract numerous and diverse pollinators, particularly small bees, wasps, and beetles. Weed control is essential for good establishment and seed production. Can be harvested with a combine if plots are weed free. Seed is long-lasting under refrigeration.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Not recommended for this species.

‌‌Greenhouse

Seed pre-treatment: Dry cold stratify 12 weeks at 40° F.

Sowing: Surface sow seed in greenhouse two months before last frost free date. Water carefully (fine mist) to prevent seed from splattering out of containers. 

Transplanting: Transplant into a weed barrier at 8 - 12 in intervals. Plants spread clonally, so the weed barrier can be removed by the third season, but seed production typically declines by the fourth season.

‌Appendix A

Stand management

Weeds: Plastic mulch or weed barrier suppresses many weeds during the first year or two. Hand rogue weeds, being careful not to uproot seedlings or disturb roots and rhizomes of the mountainmint. An anecdotal report from a commercial native seed grower suggests that cultivation within mountainmint rows weakens plants and can cause loss of the crop.

Pests: None noted.

Diseases: None noted.

Seed production

First harvest: Some flowering and seed production first year from greenhouse grown transplants.

Yield: 25-70 bulk pounds/acre in weed barrier, 15-45 bulk pounds/acre bare soil.

Stand life: Peak harvests second-third year. In proper soils with good management, stand and seed production persists at least into fourth year.

Flowering date: Flowering occurs mid-July into August.

Seed maturity/Harvest date: Mid September to early October.

Seed retention: Holds seed well, shattering occurs mid to late October.

Harvest date range at TPC (2003-2007): Sept 18 - Oct 21

Recommended harvest method: Combine 

Appendix B

Seed cleaning and storage

Cleaning process: Pre-clean by scalping through 1/2 in and 1/4 in mesh to remove large particles and make flowable, then air-screen. (No awns or appendages to remove).

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zones 1 (northern Iowa), 2 (central Iowa), and 3 (southern Iowa)

References

Chayka, K. (n.d.). Pycnanthemum virginianum (Virginia mountain mint). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/virginia-mountain-mint 

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Mountain mint. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 221). University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). Common mountain mint - Pycnanthemum virginianum. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/cmt_mintx.htm 

Houseal, G. A. (2007). Forbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 46–47). Tallgrass Prairie Center - University of Northern Iowa.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

Runkel, S. T., & Roosa, D. M. (2009). Virginia mountain mint. In Wildflowers of the tallgrass prairie: The upper Midwest (2nd ed., pp. 218–219). University of Iowa Press.

USDA NRCS National Plant Data Team. (n.d.). Pycnanthemum virginianum (L.) T. Dur. & B.D. Jacks. ex B.L. Rob. & Fernald. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=PYVI

Species Guide Updated 12/8/2025

Fragaria virginiana Duchesne 

Alternate Common Names: wild strawberry, common strawberry

Scientific Synonyms: Fragaria australis, Fragaria canadensis, Fragaria grayana, Fragaria terrae-novae

Family: ‌rose family (Rosaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

perennial, spreading by runners to form extensive clones.

Height: 4-8 in  

Leaves and stem

leaves basal, palmately compound; oval shaped leaflets (3) are up to 2.5 in long and 1.5 in wide with coarsely toothed margins and often finely haired, especially on the undersides; stems are sprawling stolons, often reddish in color, that root at the tips where new plants can emerge.

Flower, fruit and seedhead

Flower: regular, five-petaled, 1/2 in diameter, petals white, stamens and pistils in center of flower yellow, 4-6 flowers in a loose cluster that is usually shorter than the leaves.

Fruit/seedhead: 1/2 in globular to ovoid “berry” with numerous achenes (“seeds”) in pits on the berry’s surface, bright red at maturity.

Pollination: Insects such as bees, flies, and butterflies.

Seed

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 83,000 (Prairie Moon)

1000 seed weight: 0.46g (Seed Information Database)

Description: “Seed” is a reddish-brown achene, 1.2-1.8 mm in diameter, roughly egg-shaped.

Typical seed test 

PLS: 83.35%

Purity: 99.81%

Germination: 21% 

Dormancy: 61%

TZ: 85%

(averages obtained from 1 test of a purchased seed lot, and 1 test of seed produced at TPC)

Habitat and range

‌Habitat: Dry to moist soil; partial to full sun; prairies, meadows, woodland openings and edges, roadsides, along railroads, savannas, limestone glades; Wetland Indicator Status is Facultative Upland (FACU) for the Midwest.

Conservation status: Global- G5, secure; Louisiana- S1, critically imperiled; Nevada- S2, imperiled; Illinois-  S2/S3, imperiled to vulnerable (NatureServe) 

General Comments

Virginia strawberry can be found in the “understory” layer of most remnant prairies in Iowa. These small plants pack a large ecological punch. They flower early in the season, providing nectar and pollen resources for many species of small bees, flies, and skipper butterflies. Various herbivorous insects and mammals feed on the leaves, and the fruits are eaten by birds, mammals, and even reptiles (turtles), which disperse the seeds. When wild strawberries were abundant across the Iowa landscape prior to agricultural conversion, the fruits were an important early summer food for both Native people and Euro-American settlers. Virginia strawberry is one of the species that produced the cultivated strawberry through hybridization. Propagation and processing of this species is not difficult compared to other prairie forbs, and the most significant barrier to seed availability is probably the cost of labor required to pick the berries several times during the 2-3 week fruiting season.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience with direct seeding this species for seed production.

 

‌‌Greenhouse

Seed pre-treatment: 8 weeks cold/moist stratification

Sowing: Sow seed in greenhouse 8-10 weeks before average frost free date; spread stratified seed on germination flats and lightly cover (1/8 in or less) with germination mix; move seedlings to plugs when they have a pair of well-developed true leaves.

Transplanting: When plugs are well rooted and danger of frost is past, harden off seedlings and transplant into weed-free beds prepared with biodegradable paper mulch weighted with clean straw. Mulch must be biodegradable so that the new plantlets that form at the ends of stolons can grow roots into the soil.

‌Appendix A

Stand management

Weeds: Biodegradable mulch in the first growing season suppresses most weeds; mowing at the highest setting of a typical riding mower after the fruiting season keeps weeds from becoming overly competitive in the second year.

Pests: Mammalian herbivores may browse foliage, and birds and small mammals consume fruits.

Diseases: None noted, though diseases that affect commercially grown strawberries such as botrytis molds may become a problem.

Plot renewal: Commercially grown strawberries are known to produce more fruit at the edges of plots. Since wild strawberries are closely related to the cultivated varieties, they may behave similarly, and techniques of cultivation, fertilization, and irrigation that are used by commercial strawberry farms may be beneficial. We will update this information as we gain more experience.

Seed production

First Harvest: Plants flower and set fruit in the second year after planting.

Yield/Acre: 17-18 lbs of seed per acre (extrapolated from first year’s production of one production plot); it takes roughly 30 pounds of berries to obtain a pound of seed.

Stand Life: Probably long-lived, but production may decline as plots grow densely in subsequent years; plants at the edges of clones may set more fruit than those within dense patches; techniques used for “renewing” cultivated strawberry production such as rototilling narrow strips through beds may be helpful.

Flowering Date: May in northern Iowa

Seed maturity/Harvest date: late May to mid June in northern Iowa

Seed retention: There is a risk of seed loss from animals consuming the fruit or from fungal diseases; during the fruiting season (2-3 weeks), berries must be picked every 2-3 days.

Harvest date range at TPC: May 26 to June 13 (first harvest, 2024)

Recommended Harvest Method: Hand pick every other day. The labor required to harvest the small berries is significant: it took over 40 person-hours to gather ripe berries from an 840 sq ft plot every few days over a 19 day period, yielding 11.52 lbs of fruit and 5.47 oz of clean seed.

Appendix B

Seed cleaning and storage

Cleaning process: Place 2 parts water to 1 part fruit in a blender and process for 30 seconds. (Blender blades do not need to be altered or wrapped.) Pour the resulting mash into a 5 gallon bucket and add additional water. Stir, then allow the filled seed to settle out. Pour off the floating material, being careful to save the heavy seed at the bottom (J. Carstens, USDA-NCRPIS, personal communication, January 10, 2022). Spread the seed onto muslin cloth and place in front of a fan to dry. Airscreening will remove remaining debris.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone NI

The map below shows the collection locations for populations used in development of this ecotype on a base map of the Generalized Provisional Seed Transfer Zones of the US Forest Service.

References

Chayka, Katy. (n.d.). Fragaria virginiana (wild strawberry). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/wild-strawberry

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Wild strawberry. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 301). University of Wisconsin-Madison Arboretum.

Gleason, H. A., & Cronquist, A. (1991). Rosaceae. In Manual of Vascular Plants of Northeastern United States and Adjacent Canada (2nd ed., p. 242). The New York Botanical Garden. 

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 28, 2024).

Staudt, G. (2020, July 30). Fragaria virginiana (Miller). Flora of North America. http://dev.floranorthamerica.org/Fragaria_virginiana 

University of Minnesota Extension. (2025). Strawberry Farming. https://extension.umn.edu/fruit-and-vegetable-farming/strawberry-farming 

USDA NRCS National Plant Data Team. (n.d.). Fragaria virginiana Duchesne. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=FRVI

Species Guide Updated 2/3/2025

Tradescantia ohiensis Raf. 

Alternate Common Names: Ohio spiderwort, common spiderwort, cow-slobbers, snotweed, smooth spiderwort

Scientific Synonyms: Tradescantia canaliculata Raf., Tradescantia foliosa Small, Tradescantia incarnata Small, Tradescantia ohiensis Raf. var. foliosa (Small) MacRoberts, Tradescantia reflexa Raf., Tradescantia barbata

Family: ‌dayflower or spiderwort family (Commelinaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial from fibrous, fleshy roots.

Height: 1.5 -2.5 ft  

Leaves and stem

Leaves smooth, grass-like and almost succulent with a waxy bluish-green sheen, alternate, joining main stem as a sheath, generally hairless at maturity although leaves of seedlings may have hairs; stem smooth, unbranched.

Flower, fruit and seedhead

Flower: Clusters of few to many buds at stem tip and upper leaf axils; flower buds bent downwards within a cluster, bending upwards on smooth flowering stalks as each bud flowers; flowers with three blue-violet petals (occasionally white to light purple) and 6 yellow anthers with fine violet hairs at base; sepals smooth and hairless (helping distinguish this species from T. bracteata); each flower opens for a day, primarily in the morning hours.

Fruit/seedhead: Dark gray to black seeds develop inside three-parted capsules that split open and drop seed at maturity, starting at the base of a flower cluster.

Pollination: Insects, primarily bumblebees. Spiderworts produce pollen but no nectar.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 8,000 (IA NRCS)

Seeds per pound: 128,000 (IA NRCS)

1000 seed weight: 3.66 g (Seed Information Database)

Description: Seeds develop inside three-parted capsules that split open and drop seed at maturity. Seed coats are dark gray to black with intricate, wrinkled ornamentation.

Typical seed test 

PLS: 91% (n = 11)

Purity: 98% (n = 10)

Germination: 6% (n = 7)

Dormant: 89% (n = 8)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Mesic soils, prefers sandy soils in remnant prairies and open woodlands, often in areas with some disturbance; Wetland Indicator Status is Facultative Upland (FACU) for the Midwest; full sun and well-drained loam soils preferred for seed production.

Conservation status: Global- G5, secure; New Jersey- S2, imperiled. (NatureServe) 

General Comments

This species is easily propagated in the greenhouse for transplanting into production beds. Plants establish readily in prairie restorations and will spread with good management. Timing of seed harvest is challenging, since flowering and seed maturity occur gradually, and the sepals in the flower clusters may still appear green and fleshy even after much of the seed has dropped. Also, plants have a slimy, sticky sap (hence the unglamorous but obvious common name ‘snotweed’), which makes direct combining inadvisable.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Row spacing: 30-36 in rows

PLS pounds/acre: 4.5

Seeds per linear foot: 40 

Seeding depth: 1/4 in 

Seeding method: native seed drill

Seeding time: dormant season

Weed control: Prepare clean, firm, weed free seedbed prior to seeding.

 

‌‌Greenhouse

Seed pre-treatment: High percentage of dormancy, seed must be wet stratified 12 weeks at 40°F.  

Sowing: Sow seed at 1/4 in depth in greenhouse 2 months before the last frost-free date.  

Transplanting: Transplant into bare soil at 30-36 in row spacing or into a weed barrier at 8-12 in spacing after all danger of frost is past.

‌Appendix A

Stand management

Weeds: Post emergence grass herbicide, tillage, hand roguing.

Pests: None noted. Rabbits and deer will browse foliage.

Diseases: None noted.

Seed production

First harvest: Some flowering and seed set ( 24-48 bulk pounds/acre) at the end of the first growing season from greenhouse grown transplants. 

Yield: 40-100 bulk pounds/acre (per acre yields extrapolated based on production from 3 plots, not all of which were harvested each year)

Stand life: Peak harvests in the second and third full growing season after establishment. Seed production declined somewhat 4th year and was about half peak harvest 5th year. Chisel plowing can reinvigorate stands. Spiderwort is reportedly tolerant of low rates (1%) of glyphosate.

Flowering date: Late May - late June in northern Iowa

Seed maturity/Harvest date: June - mid-July in northern Iowa

Seed retention: Shattering occurs as soon as seed ripens in each capsule within a cluster. Monitor plots frequently during the later part of the flowering season. Turn over flower clusters and observe for opened capsules. Aim to harvest when a few capsules are open on most heads even though some flowers may still be present. The color of sepals changes as the capsules mature; this is helpful but variable and not a consistent indicator of readiness.

Harvest date range at TPC (2003-2023): June 24 - July 23 (but first year stands from transplants may mature much later than is typical)

Recommended harvest method: Hand pick seed heads and dry on tarps for several days with good air circulation. If piles are thick, turn often to avoid mold. Most seed will be released from capsules as they dry, and threshing largely entails simply scalping off the dried vegetative material. Large fields may be machine swathed, but seed will shatter out of heads as material dries down. 

Appendix B

Seed cleaning and storage

Cleaning process: Pre-clean air-dried material by scalping through 1/2 in and 1/4 in mesh to remove large particles, and then air-screen. Hard seed coats can visually mask seed quality. Aspiration (air screening) of seed is critical to remove unfilled but otherwise normal-looking seed.

Seed storage: cool/dry (50°F, 30% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone 1 (northern Iowa), Zone 2 (central Iowa), and Zone 3 (southern Iowa)

References

Chayka, K. (n.d.). Tradescantia ohiensis (Ohio spiderwort). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/ohio-spiderwort 

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Common spiderwort. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 155). University of Wisconsin-Madison Arboretum.

Gleason, H. A., & Cronquist, A. (1991). Commelinaceae. In Manual of Vascular Plants of Northeastern United States and Adjacent Canada (2nd ed., p. 655). The New York Botanical Garden. 

Hilty, J. (2019). Ohio spiderwort - Tradescantia ohiensis. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/oh_spiderwortx.htm 

Houseal, G. A. (2007). Forbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 54–55). Tallgrass Prairie Center - University of Northern Iowa.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

USDA NRCS National Plant Data Team. (n.d.). Tradescantia ohiensis Raf. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=TROH

Species Guide Updated 12/11/2025

Asclepias tuberosa L.

Alternate Common Names: butterfly weed, pleurisy root, yellow milkweed, orange swallowwort, orangeroot, whiteroot, Indian posy,  windroot, Canada tuber, Canada flux, chigger flower

Family: ‌milkweed family (Asclepiadaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial with a woody taproot that forms elongated tubers, can form clumps of many stems but does not spread by rhizomes.

Height: 1-2.5 ft  

Leaves and stem

Alternate leaves are lance-shaped with entire margins and dense to scattered hairs, short stalked or nearly sessile on the stem; stems are visibly hairy, branched, green to reddish in color. Unlike other milkweeds, butterfly milkweed has no milky sap.

Flower, fruit and seedhead

Flower: Orange (sometimes red or yellow) blooms, 5-parted, in flattened clusters of up to 25 flowers on tips of branches.

Fruit/seedhead: Seedpods (follicles), 4-6 in long, often in clusters, covered in peachlike fuzz, seeds bear a silky, white “parachute” and are distributed by the wind.

Pollination: Insects, particularly butterflies, bees, and wasps.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 4,300 (IA NRCS)

Seeds per pound: 68,000 (IA NRCS)

1000 seed weight: 6.76 g (Seed Information Database)

Description: Seeds are flat and chocolate-brown, about 1/4 in by 3/16 in with a tuft of fine filaments (floss).

Typical seed test 

PLS: 93% (n = 12)

Purity: 100% (n = 12)

Germination: 63% (n = 8)

Dormant: 48% (n = 9)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Dry to mesic, well-drained soil; full sun; high quality remnant prairies, savannas, glades, roadsides.

Conservation status: Global- G5, secure; Maine- SX, presumably extirpated; Vermont- SH, possibly extirpated (NatureServe) 

‌

General Comments

The bright orange flowers make this a desirable species for horticultural displays as well as prairie reconstructions. This species, like other members of the genus Asclepias, is an important host plant for monarch butterfly caterpillars. Seeds germinate readily in the greenhouse with proper stratification or use of gibberellic acid. Seedlings require care in transplanting because of the taproot structure. Butterfly milkweed does best in very well-drained soils. Requires hand-harvesting as pods ripen.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Row spacing: 30-36 in rows

PLS pounds/acre: 8.5 (40 seeds/linear foot)

Seeding depth: 1/4 in

Seeding method: native seed drill

Seeding time: dormant season

Weed control: Prepare clean, firm, weed free seedbed prior to seeding.

 

‌‌Greenhouse

Seed pre-treatment: Wet stratify 8 weeks at 40° F or treat for 24 hours with 250-ppm gibberellic acid.

Sowing: Sow seed in greenhouse two months before last frost free date. Susceptible to damping off in the greenhouse. Use sterile potting mix with added perlite, sanitize planting materials, and provide adequate ventilation. Also vulnerable to greenhouse pests such as thrips and aphids. If possible, empty and sanitize greenhouse between growing seasons to reduce pest pressure.

Transplanting: Plant into bare soil in 36 in rows or weed barrier at 12 in intervals.

‌Appendix A

Stand management

Weeds: Mow or cultivate between rows and/or use a weed barrier. Post-emergence grass herbicide, tillage, and/or roguing may be used to control weeds. Always read and follow label instructions.

Pests: Yellow milkweed aphids on upper portions of plant, including pods. Light infestations may be controlled by naturally occurring aphid predators and parasites. Heavy infestations can cause abortion of pods and failure of crop.  Monarch larvae eat foliage and pods, but not a serious problem on this milkweed species. Milkweed bug nymphs feed on developing seeds within pods. In small scale plantings, manual removal of clusters of bug nymphs can improve seed quantity and quality.

Diseases: Susceptible to various fungi, bacteria, a phytoplasma, and protozoan pathogens (Borders and Lee-Mäder, 2014).

Hybridization risk: Hybrids have been found between Asclepias tuberosa and some related species in the genus Asclepias, however it appears to be rare.

Seed production

First harvest: Some flowering and minimal seed production is possible in the planting year with greenhouse transplants.

Yield: 18-214 bulk pounds/acre (yields extrapolated based on production from 6 plots) 

Stand life: Peak harvests are typically in the second year. Stand persists in well-drained soils if disease free, but seed production may decline significantly in subsequent years. Aeration of the soil may improve stand life and productivity.

Flowering date: mid-June - mid-August in northern Iowa

Seed maturity/Harvest date: mid-August - mid-October in northern Iowa

Seed retention: Seed dispersed by wind soon after pods split open.

Harvest date range at TPC (2003-2023): Aug 10 - Oct 14

Recommended harvest method: For small plots, check daily and hand harvest as pods ripen. Ripe pods usually have a blush of yellow (somewhat like a ripe peach) and split readily with an audible “pop” when gently squeezed at the “seam.” Seeds are mature if they appear chocolate brown. If they’re still creamy white, leave the pod unpicked for another day or two.

Appendix B

Seed cleaning and storage

Cleaning process: Seeds can be separated from freshly picked pods with a hammer mill, or from dried pods using a debearder. Winnow the debearded material through a coarse screen on a day with a steady, gentle wind or in front of a box fan to reduce the bulk and fluff, then air-screen.

Seed storage: Stores well in refrigerated conditions (32-40° F, 40-60% RH).

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Project Zones 1, 2, and 3; Glacial Lake Albany Germplasm (NY)

Cultivated variety (cultivars): Horticultural varieties may also exist.

References

Borders, B. & Lee-Mäder, E. (2014). Milkweeds, A Conservation Practitioners Guide. Xerces Society for Invertebrate Conservation. https://www.xerces.org/publications/guidelines/milkweeds-conservation-practitioners-guide 

Chayka, K. (n.d.). Asclepias tuberosa (butterfly-weed). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/butterfly-weed 

Hilty, J. (2019). Butterfly milkweed - Asclepias tuberosa. Illinois Wildflowers.  https://www.illinoiswildflowers.info/prairie/plantx/btf_milkweedx.htm 

Houseal, G. A. (2007). Forbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 28–29). Tallgrass Prairie Center - University of Northern Iowa. 

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

Runkel, S. T., & Roosa, D. M. (2009). Butterfly milkweed. In Wildflowers of the tallgrass prairie: The upper Midwest (2nd ed., pp. 128–129). University of Iowa Press.

USDA NRCS National Plant Data Team. (n.d.). Asclepias tuberosa L.. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=ASTU

Species Guide Updated 12/2/2024

Eryngium yuccifolium Michx. 

Alternate Common Names: button snakeroot, rattlesnake master, rattlesnake-master, yucca-leaf eryngo, corn snakeroot, water-eryngo, rattlesnake flag, rattlesnake weed

Family: ‌carrot family (Apiaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial from a central taproot; forms small clumps through offsets after blooming.

Height: 2-5 ft  

Leaves and stem

Tough, fibrous, yucca-like leaves are mostly basal, with a waxy surface and widely spaced spiny teeth along margins; stem is hairless, waxy and rigid, pale bluish green in color.

Flower, fruit and seedhead

Flower: Spherical flowerheads composed of numerous small white flowers are arranged on short branches on the upper portion of the plant.

Fruit/seedhead: Seed head with prickly bracts turns golden-tan by winter; mature seed heads are dark brown when wet.

Pollination: Insects, predominantly bees and wasps, but also butterflies, flies, moths, and beetles.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 7,500 (IA NRCS)

Seeds per pound: 120,000 (IA NRCS)

1000 seed weight: 3.82 g (Seed Information Database)

Description: Typical “seed units” are one-seeded scaly fruits, 3/16 in long. 

Typical seed test 

PLS: 93% (n = 10)

Purity: 98% (n = 9)

Germination: 19% (n = 8)

Dormant: 43% (n = 8)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Dry-mesic to wet-mesic soil; full sun; occurs in medium to high quality remnant prairies, savannas, and limestone glades; Wetland Indicator Status is Facultative (FAC) for the Midwest. Well-drained loamy soils preferred for seed production.

Conservation status: Global- G5, secure; Maryland- SH, possibly extirpated; Nebraska- S1, critically imperiled; Michigan and Virginia- S2, imperiled; Minnesota and Ohio- S3, vulnerable (NatureServe) 

General Comments

Greenhouse propagation is recommended for this species. It grows readily, and produces some seed the first year from transplants. Potentially high seed yield. Fairly straightforward to combine harvest and air-screen clean.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Row spacing: 30-36 in rows

PLS pounds/acre: 3.25

Seeds per linear foot: 40

Seeding depth: 1/4 in

Seeding method: native seed drill

Seeding time: dormant season 

Weed control: Prepare a clean, firm, weed free seed bed prior to seeding.

 

‌‌Greenhouse

Seed pre-treatment: Wet stratify 8-12 weeks at around 40° F.

Sowing: Sow seed (1/4 in deep) in greenhouse two months before last frost free date.

Transplanting: When roots are developed enough to produce a sturdy plug, harden off, then transplant into bare soil in rows or weed barrier at 8-12 in intervals after all danger of frost.

‌Appendix A

Stand management

Weeds: Weed barrier or plastic mulch suppresses weeds during the first year. Mow/cultivate between rows. Post emergence grass herbicide, tillage, and/or hand roguing prevent weed seed contamination of crop. Anecdotal reports from commercial seed growers suggest that this species may persist and produce well within a matrix of grasses, including non-native cool season species, which may help suppress other weeds.

Pests: None noted.

Diseases: Cucumber mosaic virus detected in populations in Ohio (Whitten and Nameth, 2004).

Seed production

First harvest: Small harvest first growing season if greenhouse propagated in March and planted into a weed-barrier in spring. Flowering and harvest may be delayed in the planting year. First harvest in second year if direct seeded.

Yield: 180-560 bulk pounds/acre (yields extrapolated from harvest records from 5 plots)

Stand life: Peak harvests in the second to third years. Stand declines fourth year.

Flowering date: mid July-mid August in northern Iowa

Seed maturity/Harvest date: early October in northern Iowa

Seed retention: Shattering occurs mid to late October

Harvest date range at TPC (2003-2023): Sept 7 - Oct 25

Recommended harvest method: combine 

Appendix B

Seed cleaning and storage

Cleaning process: Pre-clean combined material by scalping thru 1/2 ft and 1/4 in mesh to remove large particles and make flowable, then air-screen. (Brushing is not needed; no awns or appendages to remove.)

Seed storage: cool/dry (33-50° F, 30-50% RH).

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Project Northern Iowa Germplasm (IA Zone 1), Central Iowa Germplasm (IA Zone 2), Southern Iowa Germplasm (IA Zone 3)

References

Chayka, K. (n.d.). Eryngium yuccifolium (rattlesnake master). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/rattlesnake-master 

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Rattlesnake-master. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 45). University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). Rattlesnake master - Eryngium yuccifolium. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/rattlesnakex.htm 

Houseal, G. A. (2007). Forbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 34–35). Tallgrass Prairie Center - University of Northern Iowa.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

Runkel, S. T., & Roosa, D. M. (2009). Rattlesnake master. In Wildflowers of the tallgrass prairie: The upper Midwest (2nd ed., pp. 130–131). University of Iowa Press.

USDA NRCS National Plant Data Team. (n.d.). Eryngium yuccifolium Michx. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=ERYU

Species Guide Updated 12/4/2025

Gentiana andrewsii, Griseb. 

Alternate Common Names: bottle gentian, closed gentian, barrel gentian, blind gentian, cloistered gentian, Andrew’s gentian, fringe-top bottle gentian

Family: ‌gentian family (Gentianaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial from a stout taproot.

Height: 1-2 ft  

Leaves and stem

Leaves opposite, lance-shaped, 4 in long and up to 2 in wide, with a smooth margin, glossy and hairless surface, and sessile (stalkless) on the stem but not clasping; stem smooth, light green or purple, unbranched.

Flower, fruit and seedhead

Flower: Five petals fused into a tube with an elongated, balloon-like shape that never opens, 1 to 1 1/2 in long, violet-blue (occasionally white or pink), in dense clusters at stem ends and upper leaf axils.

Fruit/seed head: Petals wither but are retained as a sheath around the developing capsule, 1 in long, straw-colored at maturity, with two persistent, curved styles at the tip that protrude from the dried corolla when ripe and a seam that splits along each side when seed matures, releasing numerous tiny, light, winged seeds that are dispersed by wind or water.

Pollination: This species is effectively pollinated only by bumble bees that are strong enough to push their way into the closed, bottle-shaped flowers.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 280,000 (IA NRCS)

1000 seed weight: 0.06g (Seed Information Database)

Description: Very tiny, teardrop-shaped golden seeds are surrounded by a flattened pale wing, making them look like miniature fried eggs; inclusive of the wing, they are about 1 mm wide and 2 mm long.

Typical seed test 

PLS: 85% (n = 11)

Purity: 85% (n = 10)

Germination: 4% (n = 9)

Dormancy: 82% (n = 9)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Moist soil; partial to full sun; prairies, openings in floodplain forests, thickets, fens; Wetland Indicator Status is Facultative Wetland (FACW) for the Midwest; irrigation is needed for seed production.

Conservation status: Global- G5, secure; Delaware and Massachusetts- S1, critically imperiled; Maryland and Vermont- S2, imperiled; in all other states within its natural range, status is S4 (apparently secure) to S5 (secure) or unranked (NatureServe) 

General Comments

One of the most charming plant-insect relationships to observe in the prairie is that between closed bottle gentian and its sole pollinators: bumble bees. Even large, strong bumble bees have to work hard to force their way past the tightly pleated tips of the closed flowers. Smaller bumble bees disappear completely inside the “bottle” while the rear ends of larger bumbles protrude as they feed actively on the nectar inside. This species and other late flowering gentians are important resources for the bumble bee gynes (new females) that emerge in fall and must be well fed to survive the winter and start new colonies in the spring. Closed bottle gentian grows among sedges and grasses in wet prairies and at the edges of fens in our region. Irrigation is needed for seed production.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Not recommended for this species.

 

‌‌Greenhouse

Seed pre-treatment: 90 day cold/moist stratification or treat with 125 ppm to 250 ppm GA-3 solution for 24 hours just prior to sowing.

Sowing: Surface sow on saturated potting mix at least 4 months before last frost or expected planting date. Sow directly into plugs (aim for 3-5 seeds per cell) as seedlings are delicate and easily damaged by dibbling. Use caution when watering to avoid splashing seed from soil. Alternatively, seed may be started in phytoagar with 50-60 ppm GA-3 and transplanted to plugs with a small piece of agar left around the root. This method produces high rates of germination. Seeds may otherwise be slow and spotty in germination, and seedlings are always very small and slow growing. If seed in soil germinates poorly, spraying the soil surface with 500 ppm solution of GA-3 can help produce a new flush of seedlings. Be careful when spraying this solution to avoid contaminating surfaces or potting media, as many species are very sensitive to it.

Transplanting: Keep seedlings in plug flats until well-rooted, usually several months. Seedlings started in the greenhouse in spring will remain as rosettes until late summer to early fall, when some seedlings may begin to form leafy stems. At this point, they will still be fairly delicate plugs but should have sufficient root growth to be hand transplanted into irrigated, plasticulture production rows. If planted in fall, some plugs may frost-heave, but if re-seated in their holes in time, they may survive. Walk the rows frequently as the ground thaws, and seat plugs in their holes using a carefully placed boot.

‌Appendix A

Stand management

Weeds: Prepare clean, weed-free beds. Plastic mulch suppresses weeds in the first season or two. We have tried planting closed bottle gentian with a wetland grass, bluejoint, to suppress weeds and provide some support and protection from deer. A better companion might be a tufted (cespitose) wetland sedge such as Carex scoparia, as bluejoint spreads by rhizomes to form dense stands that begin to suppress the gentians, except those on the edges of the row, in the third growing season. 

Pests: Deer like to eat the flower clusters. Weeds or a companion grass within the plots discourage this. The larvae of a moth (Endothenia hebesana) feed on developing seeds within capsules.

Diseases: None noted.

Hybridization risk: This species is known to hybridize with other species in the genus Gentiana and a related genus (Gentianella quinquefolia). Maintain separation distances between plots of these species.

Seed production

First harvest: Expect the first flowers and seed set in the year after planting. Peak yields are in the second through fourth growing seasons.

Yield/acre: 10-15 pounds per acre of very small, light seed (extrapolated from harvests of three plots at TPC)

Stand life: Stands may persist for six years or more, but yields decline in the fifth year and later.

Flowering date: late August through mid October in northeast Iowa

Seed maturity/Harvest date: late October through early November in northeast iowa

Seed retention: Fairly high risk of shattering once capsules extend past the dried corolla tube and split open, especially during high wind events. The seeds are very light and easily dispersed.

Harvest date range at TPC (2003-2006): September 9 - November 20

Recommended harvest method: Hand pick as the capsules ripen. 

Appendix B

Seed cleaning and storage

Cleaning process: Shake and/or crush hand collected material to release seeds from capsules, pass through 1/4 in and 1/8 in mesh to remove larger particles, then airscreen. Static buildup can be a problem in handling this seed.

Seed storage: Cool/dry (33-50° F, 30-50% RH); seed apparently lasts only a few years in storage.

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone NI (northern Iowa, aligned with the Generalized Provisional Seed Zones of the US Forest Service)

References

Barnd, B., Hardy, R. Hatfield, M.J., O’Connor, M., Tony, Zimlich, R.L. (2025, February 8) Species Endothenia hebesana - Verbena Bud Moth - Hodges#2738. BugGuide. https://bugguide.net/node/view/132143 

Bower, Andrew D.; St.Clair, J. Bradley; Erickson, Vicky. 2014. Generalized provisional seed zones for native plants. Ecological Applications. 24(5): 913-919.

Chayka, K. (n.d.). Gentiana andrewsii (bottle gentian). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/bottle-gentian 

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Bottle gentian. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 203). University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). Bottle gentian - Gentiana andrewsii. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/bt_gentianx.htm 

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

Runkel, S. T., & Roosa, D. M. (2009). Closed gentian. In Wildflowers of the tallgrass prairie: The upper Midwest (2nd ed., pp. 258–259). University of Iowa Press.

USDA Forest Service and Southern Regional Extension Forestry. (n.d.). Propagation protocol database. RNGR - Reforestation, Nurseries, and Genetic Resources. https://npn.rngr.net/propagation 

USDA NRCS National Plant Data Team. (n.d.). Gentiana andrewsii Griseb. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=GEAN

Species Guide Updated 12/23/2025

Eupatorium perfoliatum L.

Alternate Common Names: boneset, thoroughwort

Scientific Synonyms: Eupatorium chapmanii Small, Eupatorium perfoliatum var. colpophilum Fernald & Griscom, Eupatorium perfoliatum var. cuneatum Engelmann

Family: ‌aster or sunflower family (Asteraceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial, short-rhizomatous, spreads slowly to form small colonies.

Height: 2-4 ft

 

Leaves and stem

Leaves join around the stem making them look like one leaf (perfoliate) and then taper to a point, opposite arrangement (rarely whorled), leaf margins are wavy with small teeth (crenulate), leaf surfaces have a wrinkled appearance, upper and lower leaf sides are hairy; stems are hairy, erect, and branched in the upper portion of the plant.

 

Flower, fruit and seedhead

Flower: Tiny heads (1/4 in) of up to 15 disc florets (no visible “petals” or rays), grouped in flat-topped to slightly domed clusters of dozens to hundreds of heads; flower clusters appear fuzzy due to thin styles that extend from each floret.

Fruit/seedhead: Clusters become fluffy from the center outwards as seeds mature and pappus expands.

Pollination: Insects, particularly bees, butterflies, flies, beetles, and wasps.  

 

Seed

Appendix D

‌Seed characteristics 

Seeds per ounce: 160,000 (IA NRCS)

1000 seed weight: 0.11 g (Seed Information Database)

Description: Long slender, dark gray seeds (achenes) up to 2.5 mm long with a short tuft of white hairs (pappus).

Typical seed test 

PLS: 68% (n = 6)

Purity: 71% (n = 6)

Germination: 16% (n = 5)

Dormant: 81% (n = 5)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Moist to wet, organic-rich soil; full sun; wet pastures, sedge meadows, fens; The USDA classifies it as an Obligate Wetland species in the Midwest region. It benefits from irrigation in production systems.

Conservation status: Global- G5, secure; Kansas- S3, vulnerable (NatureServe)

‌

General Comments

The clouds of sweet-scented flowers attract a diverse assemblage of pollinating insects. Bitter compounds in the foliage deter mammalian herbivores, although some moth larvae use common boneset as a host plant. This species has traditional medicinal and ceremonial uses among Native tribes within its range, and was adopted as a treatment for colds and fevers by colonial settlers. It is currently under investigation by researchers in Germany and India for use in treatment of viral illnesses such as colds, flu, and dengue fever as well as malaria. Caution: this plant also contains phytochemicals that may be toxic to the liver.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience direct seeding this species for seed production. It reportedly has low germination rates in direct seedings. High seeding rates and fall planting are recommended.

‌‌Greenhouse

Seed pre-treatment: 60 days cold-moist stratification.

Sowing: Seed is small and should be surface sown. If started in germination flats, transplant to individual plugs when seedlings have their first pair of true leaves, about 4 weeks after seeding.

Transplanting: Seedlings are ready to transplant to the field about 6-8 weeks after being transferred to plugs, when their roots are well-branched and numerous root tips are visible at hole(s) in the base of the plug. Pop out a few plugs to check for adequate root development that will provide sturdy plugs for planting. Seedlings are fast growing and may need to be clipped back before transplanting to improve the shoot:root ratio. A week or two before transplanting, move flats outside to ‘harden off.’ (See Propagation chapter in General Information for more details).

‌Appendix A

Stand management

Weeds: In the first season after transplanting, weeds are suppressed by a plastic weed barrier. Plants spread slowly by short rhizomes; in second and subsequent years, holes in plastic may need to be expanded or plastic removed to make room for new stems. Well-established plots shade out most weeds.

Pests: None noted.

Diseases: None noted.

Soil moisture: Irrigation is necessary in most soils to obtain maximum seed yield.

Seed production

First harvest: Plants flower and set a little seed the first year when transplanted in spring.

Yield: 80-130 pounds/acre (based on 1 plot)

Stand life: unknown

Flowering date: August - September in northeast Iowa

 

Seed maturity/Harvest date: mid-September - mid-October

Seed retention: Seeds are wind dispersed soon after maturity, when fluff (pappus) expands in late September through mid-October.

Harvest date range at TPC (2022-2023): Sept 15 - Oct 7

Recommended harvest method: Watch for the centers of seed clusters to begin shattering, and pick early maturing seed heads (clip stalks below seed clusters). If some heads in a cluster are still closed (not fluffy), pull apart a few heads to see if the seeds are dark colored and separate easily from the base (receptacle). Combine the rest of the plot at peak maturity. Turn off air or combine will disperse the fluffy seeds.

Appendix B

Seed cleaning and storage

Cleaning process: If hand clipped, run dried material through a 1/4 in mesh to thresh seed from stalks. Use a brush machine (soft bristles, minimum vacuum) to remove pappus. Seed is fragile, and some seed is dehulled, even when soft bristles are used. Winnow with a box fan to separate seed from most of the pappus and chaff. Airscreen 2-3 times to finish cleaning. See Appendix C for specific settings.

Seed storage: cool/dry (33-50° F, 30-50% RH) for up to 3 years (USDA Plant Fact Sheet).

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone NI

References

Belt, S. (2009). Plant fact sheet for common boneset (Eupatorium perfoliatum L.). USDA-Natural Resources Conservation Service, Norman A. Berg National Plant Materials Center, Beltsville, MD  20705.

Chayka, K. (n.d.). Eupatorium perfoliatum (common boneset). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/common-boneset

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Boneset. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 79). University of Wisconsin-Madison Arboretum.

Eupatorium perfoliatum. (n.d.). Prairie Moon Nursery. https://www.prairiemoon.com/eupatorium-perfoliatum-boneset-prairie-moon-nursery.html 

Hilty, J. (2019). Common boneset - Eupatorium perfoliatum. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/cm_boneset.htm

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 28, 2024).

SER, INSR, RBGK, Seed Information Database (SID). (2023). Eupatorium perfoliatum. https://ser-sid.org/species/e29e87df-3177-43f1-bfcd-bc052339de84

USDA NRCS National Plant Data Team. (n.d.). Eupatorium perfoliatum L. USDA plants database. https://plants.usda.gov/plant-profile/EUPE3

Siripun, K. C., & Schilling, E. E. (2020, November 6). Eupatorium perfoliatum Linnaeus. Flora of North America. http://floranorthamerica.org/Eupatorium_perfoliatum 

Species Guide Updated 12/18/2024

Silphium laciniatum L. 

Alternate Common Names: compass plant, rosinweed, turpentine plant, polar plant, pilot-weed

Scientific Synonym: Silphium laciniatum var. robinsonii L. M. Perry

Family: ‌aster family (Asteraceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial, large 15 ft central taproot.

Height: 3-10 ft  

Leaves and stem

Leaves alternate, 12 - 24 in long, deeply lobed, densely covered in coarse hairs; stems are rounded in cross section and covered in long, coarse, spreading hairs, somewhat woody late in the season.

Flower, fruit and seedhead

Flower: Yellow composite flower heads, 3-4 in diameter, several per flowering stem.

Fruit/seedhead: Seeds (technically achenes) form only from outer fertile flowers of the central disk.

Pollination: Primarily bees

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 660 (IA NRCS)

1000 seed weight: 78.05 g (Seed Information Database)

Description: ‘Seeds’ are flat fruits (achenes), 3/8 – 1/2 in long, with a broad wing around margins, making it difficult to get a good separation between filled and unfilled seed. No plume.

Typical seed test 

PLS: 85% (n = 11)

Purity: 88% (n = 11)

Germination: 14% (n = 9)

Dormant: 73% (n = 10)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Wet-mesic to dry-mesic soil conditions; full sun; typically on high quality prairie remnants, railroads, roadsides, glades, savannas; preference is for moist, well-drained soils for seed production.

Conservation status: Global- G5, secure; Colorado- SH, possibly extirpated; Ohio, Oklahoma, and Virginia- S1, critically imperiled; Michigan- S1/S2, critically imperiled to imperiled; Kentucky and Tennessee- S2, imperiled; South Dakota- S3, vulnerable (NatureServe) 

General Comments

Compass plant is a long-lived, tap-rooted species. An individual seedling may take 2-4 years to flower in production, and flower every year thereafter for a few years. In a prairie, an individual may take 5-10 years to flower, and subsequently flower every other year or so. Silphium species (congeners) will hybridize with one another in nature, so they should be properly isolated from related species for seed production purposes (i.e. cupplant, Silphium perfoliatum; rosinweed, Silphium integrifolium; prairie dock, Silphium terebinthinaceum; etc.) (Fisher 1966, Clevinger and Panero 2000)

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Not recommended for this species

 

‌‌Greenhouse

Seed pre-treatment: Wet stratify 8-12 weeks at 40° F.

Sowing: Sow seed in greenhouse two months before last frost free date.

Transplanting: Transplant into bare soil in rows or weed barrier at 12 in intervals after all danger of frost is past.

‌Appendix A

Stand management

Weeds: Post emergence grass herbicide, tillage, hand roguing. Plastic mulch is not recommended for this species. In an informal trial at TPC, seedlings grown in plastic mulch grew more slowly and took longer to reach maturity than seedlings grown in a biodegradable paper mulch.

Pests: None noted.

Diseases: None noted.

Hybridization risk: This species is known to hybridize with related species Silphium integrifolium, S. perfoliatum, and S. terebinthinaceum. Plan plot layouts to maximize separation among these species.

Seed production

First harvest: Some flowering and seed set end of second year, most will flower during the third growing season from greenhouse grown transplants.

Yield: 40-130 bulk pounds/acre

Stand life: Peak harvests third year. Plants are very long-lived, but seed production may decline significantly in the fourth to fifth year after planting. Harvests from TPC plots also provide some evidence for fluctuating yields over time.

Flowering date: Early July to mid-August.

Seed maturity/Harvest date: Mid-August to mid-September.

Seed retention: Shattering occurs as seeds mature and dry, end of August into September.

Harvest date range at TPC (2003-2012): Aug 22 - Oct 14

Recommended harvest method: Hand collect as seed ripens for most efficient harvest of small plots, combine for larger stands when seed is mostly mature and before significant shattering. 

Appendix B

Seed cleaning and storage

Cleaning process: Pre-clean air-dried material by scalping through 1/2 in mesh and sifting through 1/4 in mesh (most seed will be retained on top of 1/4 in mesh). Brushing with soft bristles helps to break up inert matter to achieve better separation. Air-screen repeatedly to clean.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Project Zone 1 (northern Iowa), Zone 2 (central Iowa), and Zone 3 (southern Iowa)

References

Chayka, K. (n.d.). Silphium laciniatum (compass plant). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/compass-plant 

Clevinger, J. A. (2020, November 5). Silphium laciniatum Linnaeus. Flora of North America. http://floranorthamerica.org/Silphium_laciniatum 

Hilty, J. (2019). Compass plant - Silphium laciniatum. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/compassx.htm

Houseal, G. A. (2007). Forbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 50–51). Tallgrass Prairie Center - University of Northern Iowa.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

Runkel, S. T., & Roosa, D. M. (2009). Compass plant. In Wildflowers of the tallgrass prairie: The upper Midwest (2nd ed., pp. 180–181). University of Iowa Press.

USDA NRCS National Plant Data Team. (n.d.). Silphium laciniatum L. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=SILA3

Species Guide Updated 12/10/2025

Lysimachia quadriflora Sims 

Alternate Common Names: four-flower yellow loosestrife, linear-leaf loosestrife, prairie loosestrife

Scientific Synonyms: Lysimachia longifolia Pursh; L. revoluta Nuttall; Nummularia longifolia (Pursh) Kuntze; Steironema longifolium (Pursh) Rafinesque; S. quadriflorum (Sims) Hitchcock

Family: ‌myrsine family (Myrsinaceae), formerly classified in the primrose family (Primulaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial with sprawling stems that are often supported by surrounding vegetation, spreading slowly from short rhizomes to form clumps of several stems.

Height: 1-2.5 ft  

Leaves and stem

Leaves very narrow (linear), 1 1/4 to 3 1/2 in long and only up to 1/4 in wide, opposite and often with smaller secondary leaves at nodes making them appear whorled, leaves glossy and mostly hairless, often turning red in fall; stems smooth and unbranched or branching in the top half of the plant.

Flower, fruit and seedhead

Flower: Flowers regular, 1-in wide, 5-parted, nodding on slender petioles, emerging singly or in loose clusters of up to 4 flowers from upper leaf axils; petals bright yellow, often with ragged edges and faint reddish streaks or spots.

Fruit/seed head: Fruit is a nearly spherical, glossy capsule with a persistent point (the style), opens from the top at maturity and seed scatters out as the plant is shaken by the wind or passing animals.

Pollination: Insects, including generalist and specialist bees.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 90,000 (IA NRCS)

1000 seed weight: 0.28 g (Seed Information Database)

Description: Seeds 1-1.5 mm long, 3-sided, irregular in outline, concave on one side, dark or reddish brown, with a rough surface texture. Seed image includes ruler with mm markings.

Typical seed test 

PLS: 90% (n=3)

Purity: 93% (n=3)

Germination: 0.33% (n=3)

Dormant: 97% (n=3)

(averages obtained from 3 tests of purchased seed lots)

Habitat and range

‌Habitat: Moist to wet soils in full sun; wet prairies, fens, seeps, ditches; Wetland Indicator Status is OBL (obligate, almost always occurring in wetlands) in the Midwest; irrigation is needed for seed production.

Conservation status: Global- G5 (secure); Kentucky, West Virginia- SH (possibly extirpated); Alabama, Georgia- S3 (vulnerable); South Dakota, Oklahoma, Tennessee, New York, Virginia- S1 (critically imperiled); in all other states in its native range, status is S4 (apparently secure) to S5 (secure) or unranked (NatureServe) 

‌[BONAP Map]

General Comments

If we want planted prairies to better resemble remnant prairies in their diversity and species composition, fourflower yellow loosestrife is a species that should be considered for wet soils. It can be found in most wet prairies, sedge meadows, seeps, and fens in our area and even in some wet ditches where native vegetation has persisted. This species is inconspicuous due to its size except when in flower or when the foliage turns red in the fall. It can be easily distinguished from other members of its genus in our region by its very thin (linear) leaves that are only up to about 1/4 in wide. The relatively weak, slender stems of fourflower yellow loosestrife seem to lean on taller grasses, sedges, and forbs for support, and some of the plants may sprawl a bit in production settings. The nodding, intensely yellow flowers produce oils rather than nectar and are visited by specialist bees that use the oils, mixed with pollen, to provision their larvae, as well as by generalist bees that use pollen.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience with direct seeding this species for seed production.

 

‌‌Greenhouse

Seed pre-treatment: 90 days cold/moist stratification

Sowing: Surface sow in greenhouse 3 months before last frost free date. Use caution in watering to avoid splashing small seeds from soil. Seeds may be slow and irregular in germination, but keeping germination flats saturated (in a tray of standing water) may improve germination.

Transplanting: When plugs are well rooted, place them outside to harden off, then transplant at 8-12 in spacing in irrigated rows with plastic mulch.

‌Appendix A

Stand management

Weeds: Prepare clean, weed free beds. Use plastic mulch to suppress weeds in the first year or two. Mow or cultivate between rows. Hand weed or rogue out small seeded weeds or large, competitive weeds.

Pests: None noted.

Diseases: None noted.

Seed production

First Harvest: Some flowering and seed set in the first growing season from transplants. Yield doubled the following year.

Yield/Acre: 60-120 pounds per acre (extrapolated from harvests of one plot)

Stand Life: Unknown at this time, but productive stand life is probably 3-5 years. Invasion of the plots by weed species that benefit from irrigation may be a primary cause of decline.

Flowering Date: mid June through August in northeast Iowa

Seed Maturity/Harvest Date: late September to mid October

Seed retention: Moderate risk of shattering though some seed is retained in capsules into late October. 

Harvest date range at TPC (2024-2025): Sept 26 - Oct 14

Recommended Harvest Method: Combine and hand. Uneven ripening in the field presents a challenge. Observe plot frequently when the plants begin turning red in the fall and watch for open capsules. Consider harvesting when about 10-20% of the capsules are open. Crush some of the closed capsules and observe for dark colored (maturing) seed. Hand harvesting early individuals is recommended, and stems with capsules that are immature and pass through the combine can be collected and allowed to dry, and this later maturing seed can be threshed with a stationary combine. These methods can help retain diversity in the timing of flowering and fruiting in the restoration seed supply. 

Appendix B

Seed cleaning and storage

Cleaning process: Pass combined material through 1/2 in and 1/4 in screens, then airscreen repeatedly.

Seed storage: Cool/dry (33-50° F, 30-50% RH); long term viability in storage unknown at this time.

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone NI (aligned with the Generalized Provisional Seed Zones of the US Forest Service)

References

Bower, Andrew D.; St.Clair, J. Bradley; Erickson, Vicky. 2014. Generalized provisional seed zones for native plants. Ecological Applications. 24(5): 913-919.

Cholewa, A.F., Pipoly J.J. III, Ricketson, J.M. (n.d.). Myrsinaceae R. Brown. Flora of North America. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=10598 

Chayka, K. (n.d.). Lysimachia quadriflora (Prairie Loosestrife). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/prairie-loosestrife 

Hilty, J. (2019). Prairie Loosestrife, Lysimachia quadriflora. Illinois Wildflowers. https://www.illinoiswildflowers.info/wetland/plants/pr_loosestrife.html 

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: December 18, 2025).

Society for Ecological Restoration, International Network for Seed Based Restoration and Royal Botanic Gardens Kew. (2023) Seed Information Database (SID). Available from: https://ser-sid.org/ (February 2023)

USDA-NRCS. (2024). Native seeding calculator 2024 [Excel File]. Retrieved from https://efotg.sc.egov.usda.gov/#/state/IA/documents/section=4&folder=-6 

USDA NRCS National Plant Data Team. (n.d.). Lysimachia quadriflora Sims, fourflower yellow loosestrife. USDA plants database. https://plants.usda.gov/plant-profile/LYQU

Species Guide Updated 12/19/2025

Lobelia siphilitica, L. 

Alternate Common Names: blue lobelia, blue cardinal flower

Family: ‌bellflower family (Campanulaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Short-lived perennial that produces small clumps of stems from vegetative offshoots. 

Height: 1-4 ft  

Leaves and stem

Leaves alternate, elliptical to lanceolate, 2-6 in long, with margins that are serrated and wavy, and bearing scattered short hairs; stem is usually unbranched, ridged, with short hairs on the ridges.

Flower, fruit and seedhead

Flower: Dense, spike-like racemes 6 to 24 inches long at ends of stems; flowers (1 - 1 1/2 in wide) are intensely blue (occasionally white or light blue), two-lipped with a nectar tube.

Fruit/seed head: Two-chambered capsule releases numerous tiny seeds from openings at the top.

Pollination: Insects, primarily bumble bees and other large-bodied bees including the federally endangered rusty patched bumble bee; butterflies may also visit the flowers.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 500,000 seeds/oz (IA NRCS)

1000 seed weight: 0.04g (Seed Information Database)

Description: Seeds are translucent, honey-colored, and elliptical in outline with an intricate, bumpy surface texture.

Typical seed test 

PLS: 91% (n = 11)

Purity: 95% (n = 11)

Germination: 20% (n = 7)

Dormancy: 76% (n = 7)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Moist to wet soils; part shade to full sun; moist to wet prairies, fens, seeps, ditches, moist fields, openings in floodplain forests, shorelines; Wetland Indicator Status is Obligate Wetland (OBL) for the Midwest; planting in full sun in reliably moist soil or under irrigation is recommended for seed production.

Conservation status: Global- G5, secure; Maine- SX, presumed extirpated; Massachusetts and Vermont- S1, critically imperiled; Wyoming- S1/S2, critically imperiled to imperiled; Louisiana and Mississippi- S3, vulnerable; secure (S5), apparently secure (S4), or unranked in other states within its range (NatureServe) 

General Comments

Great blue lobelia blooms from mid summer through fall in prairie wetlands and woodland openings, providing nectar and pollen for its primary pollinators, long-tongued bumble bees. Hummingbirds and large butterflies also visit the flowers for nectar. The plant contains toxic and bitter compounds that make it unpalatable for most mammalian herbivores. Those same toxic alkaloids have a long history of use, in controlled doses, as medicines. The species name “siphilitica” alludes to Indigenous medicinal uses, including as a treatment for syphilis and other ailments, and one of the compounds found in great blue lobelia, lobeline, has been under recent investigation for treatment of addiction and depression. The brilliant blue color and long blooming season make these flowers attractive for home gardens as well as for larger plantings. Great blue lobelia plants are relatively short-lived in seed production, but they produce heavily for a couple of years. The seed is tiny but not particularly difficult to harvest or clean.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience with direct seeding this species for seed production.

 

‌‌Greenhouse

Seed pre-treatment: Cold/moist stratification for 60 days is recommended. Some sources suggest this step is unnecessary, however seed test results indicate that nearly 80% of seed has dormancy. Skipping the stratification step could reduce the proportion of plants with this trait in the restoration seed supply.

Sowing: Surface sow in the greenhouse at least 2 months before the last frost. Use caution when watering to avoid splashing seed. Seedlings are very tiny but fast growing, producing many fibrous roots and a leafy basal rosette, and starting the seeds in wide plugs that allow them room works well (e.g., 6X6 plug inserts in a standard 10X20 greenhouse flat).

Transplanting: When plugs are well rooted, move them outside to harden off and transplant them at 8-12 in spacing into irrigated rows with plastic mulch after danger of frost is past.

‌Appendix A

Stand management

Weeds: Prepare a clean, weed-free bed and use plastic mulch to suppress weeds in the planting year. Widening the holes or removing the mulch in the second growing season allows new offsets to grow, producing small clumps of stems. Hand weed or rogue out very small-seeded weeds to avoid contaminating the seed crop.

Pests: None noted.

Diseases: None noted.

Hybridization risk: This species is known to hybridize with related species in the genus Lobelia such as L. cardinalis and L. spicata. Maintain separation distances between production fields of these species.

Seed production

First harvest: Some flowering and seed set is expected in the establishment year, but peak harvest is in year 2.

Yield/acre: 50 - 200 pounds per acre (extrapolated from harvests of 3 production plots)

Stand life: Short-lived plants produce peak harvest in year 2, then production declines rapidly.

Flowering date: late July through September in northeast Iowa

Seed maturity/Harvest date: early to mid October in northeast Iowa

Harvest date range at TPC (2003-2011): Sept 5 - Oct 18

Recommended harvest method: Combine with air turned all the way down to avoid dispersing the tiny seeds. Hand pick early maturing stems to avoid losing their genetics from the production population. 

Appendix B

Seed cleaning and storage

Cleaning process: Pass combined material through 1/4 in mesh to remove larger debris, then airscreen. Crush handpicked stems, screen, then airscreen.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone 1 (northern Iowa), Zone 2 (central Iowa), Zone 3 (southern Iowa)

Cultivated varieties (cultivars): Horticultural selections are available for landscape design applications. However, the straight species by itself is a wonderful addition to a garden, is easy to grow from seed, and persists for years through self-seeding.

References

Chayka, K. (n.d.). Lobelia siphilitica (blue lobelia). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/blue-lobelia

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Great blue lobelia. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 234). University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). Great Blue Lobelia - Lobelia siphilitica. Illinois Wildflowers. https://www.illinoiswildflowers.info/wetland/plants/gb_lobeliax.htm  

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

Moerman, D. (2003). Native American ethnobotany database. BRIT. http://naeb.brit.org/  

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

Prairie Moon Nursery. (n.d.). Lobelia siphilitica. https://www.prairiemoon.com/lobelia-siphilitica-great-blue-lobelia-prairie-moon-nursery.html  

Society for Ecological Restoration, International Network for Seed Based Restoration and Royal Botanic Gardens Kew. (2023) Seed Information Database (SID). Available from: https://ser-sid.org/ (February 2023)

USDA NRCS National Plant Data Team. (n.d.). Lobelia siphilitica L. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=LOSI

Species Guide Updated 12/22/2025

Tradescantia bracteata, Small 

Alternate Common Names: spiderwort, prairie spiderwort, bracted spiderwort, long-bracted spiderwort, sticky spiderwort

Family: ‌dayflower and spiderwort family (Commelinaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial with fibrous roots, spreading by rhizomes to form colonies.

Height: 1/2-1 1/2 ft  

Leaves and stem

Leaves 4 to 10 in long, floppy, creased at the midvein, with smooth surface (though often with hairs on margins) and parallel veins; base of leaves sheath the stem; stem is smooth, rarely branched; plants form clumps of multiple stems from the base.

Flower, fruit and seedhead

Flower: Flowers in a terminal cluster of few to many flowers (occasionally also in leaf axils) with a prominent pair of bracts at their base as long as the stem leaves; flowers 1 in wide, 3-parted, violet to pink (occasionally white), bearing 6 stamens with hairy filaments and a single blue style; sepals are hairy, distinguishing T. bracteata from T. ohiensis (bluejacket or Ohio spiderwort); each flower blooms for one day (generally fading after morning), but flowering is staggered within a cluster; the hairy stalk supporting each flower stands up when flowering but droops once blooming is done.

Fruit/seed head: Seed capsules are 3-celled and 1/4 in long, obovoid shape, developing within the persistent hairy sepals; splitting open at maturity to release 2-6 seeds.

Pollination: Insects, primarily bees and flower flies (syrphids).

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 10,000 seeds/oz (IA NRCS)

1000 seed weight: 3.12g (Seed Information Database)

Description: Seeds dark gray (sometimes tan), oblong in outline with a dimple on one side and complex, grooved surface texture; 2-3 mm long and 1.5 mm wide.

Typical seed test 

PLS: 88% (n = 11)

Purity: 95% (n = 11)

Germination: 7% (n = 10)

Dormancy: 85% (n = 10)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Dry to mesic soil; full sun; sand prairies, black soil prairies, woodland edges, along railroads, roadsides; Wetland Indicator Status is Facultative Upland (FACU) for the Midwest; well-drained loamy soils are recommended for seed production.

Conservation status: Global- G5, secure; Michigan- SX, presumed extirpated; Wyoming- S1, critically imperiled; Arkansas and Illinois- S2, imperiled; in all other states within its natural range, status is S4 (apparently secure) to S5 (secure) or unranked. (NatureServe)

General Comments

This is an attractive, early flowering species that persists through vegetative spread and reseeding in both high quality prairies and in somewhat disturbed areas. The flowers produce pollen but no nectar, hence they are visited primarily by bees that use pollen to provision their larvae or by syrphid flies that feed directly on pollen. Once the seed matures, the above ground parts of the plants wither and plants remain dormant until the next growing season, although small shoots may emerge in fall. This species is distinguished from similar species in our region by having glandular hairs on both sepals and flower stalks and prominent bracts under the inflorescences that are as long and wide as the stem leaves. Bracted spiderwort is generally a smaller plant than T. ohiensis (bluejacket or Ohio spiderwort) and can spread vegetatively to form large colonies, while bluejacket is more clumped.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience with direct seeding this species for seed production.

 

‌‌Greenhouse

Seed pre-treatment: At least 90 days cold stratification.

Sowing: Sow about 1/4 inch deep in the greenhouse about 2 months before the last frost date.

Transplanting: When plugs are well rooted, take them outside to harden off for a week or two, then transplant in rows suitable for cultivation or at 8-12 inch intervals in plastic mulch.

‌Appendix A

Stand management

Weeds: Prepare a clean, weed-free bed. Plastic mulch suppresses weeds in the establishment year but should be removed in subsequent years to allow vegetative spread. Mow or cultivate between rows. This species appears to be fairly intolerant of competition from weeds. Planting in rows between sheets of landscape fabric might facilitate harvest by allowing capture of seed that drops as it matures, but we have not tried this.

Pests: None noted.

Diseases: None noted.

Hybridization risk: This species is known to hybridize with other members of the genus Tradescantia such as T. ohiensis (bluejacket or Ohio spiderwort). Maintain separation distances between plots of these species.

Seed production

First harvest: Expect very little flowering and seed set in the first year. Peak yields occur in year 2 and/or 3.

Yield/acre: 100-140 pounds per acre in year 2 to year 3 (extrapolated from harvests of two plots at TPC)

Stand life: Productive stand life is 3-4 years. Yields begin to decline in year 3 or 4 and after.

Flowering date: mid May to mid June in northeast Iowa

Seed maturity/Harvest date: late June to early July in northeast Iowa

Seed retention: High risk of shattering. Seed drops from the plant as each capsule matures. There is no perfect way to time the harvest. Observe plants frequently as typical harvest dates approach. Turn over seedheads and look for dry, brown, open capsules among the hairy sepals. Plan to harvest when there are some mature capsules on most plants. If whole stalks are collected, capsules will continue to mature and release seed as they dry. If planted in rows between sheets of landscape fabric, it’s possible that dropped seed could be swept or vacuumed from the fabric.

Harvest date range at TPC (2003-2022): June 24 - July 22

Recommended harvest method: When most plants have some mature capsules in their seed heads, cut entire stalks and lay on tarp to dry. Provide ventilation and turn thick piles regularly to avoid mold growth. Seed will be released onto tarp as capsules mature and can then be easily screened from the dry stalks. 

Appendix B

Seed cleaning and storage

Cleaning process: Pass material through 1/2 inch mesh to remove dried stalks, then airscreen.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone 2 (central Iowa)

References

Chayka, K. (n.d.). Tradescantia bracteata (long-bracted spiderwort). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/long-bracted-spiderwort  

Hilty, J. (2019). Prairie spiderwort - Tradescantia bracteata. Illinois Wildflowers.   https://www.illinoiswildflowers.info/prairie/plantx/pr_spiderwort.htm 

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

USDA NRCS National Plant Data Team. (n.d.). Tradescantia bracteata Small. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=TRBR

Species Guide Updated 12/22/2025

Pycnanthemum tenuifolium Schrad. 

Alternate Common Name: slender mountain mint

Scientific Synonyms: Koellia flexuosa auct. non (Walter) MacMill., Pycnanthemum flexuosum auct. non (Walter) Britton, Sterns & Poggenb., Pycnanthemum linifolium

Family: ‌mint family (Lamiaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Rhizomatous perennial that forms vegetative colonies. 

Height: 1-3 ft  

‌

Leaves and stem

Very narrow (1/8 in or less), opposite leaves with a strong mint/citrus odor when crushed; stems are slender, 4-sided, branched above, and entirely hairless, helping to distinguish this species from our other mountain mints.

Flower, fruit and seedhead

Flower: Small (1/4 in long) two-lipped, white flowers with scattered purple dots, in clusters at stem tips. 

Fruit/seed head: Seedheads are light brown when mature in contrast to the grey color of P. virginianum and P. pilosum seed heads. 

Pollination: Insects such as bees, butterflies, wasps, and beetles

Seed

 

Appendix D

‌Seed characteristics 

Seeds per ounce: 378,000 (IA NRCS)

1000 seed weight: 0.08 g (Seed Information Database)

Description: Seed units are tiny nutlets (nearly 1 mm long), developing within each tube-like calyx of the inflorescence.

Typical seed test 

PLS: 90% (n = 13)

Purity: 94% (n = 13)

Germination: 36% (n = 9)

Dormant: 45% (n = 10)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Mesic to dry-mesic soils in upland prairies; full sun; prairies, moist meadows, limestone glades, thickets, woodland openings, abandoned fields; Wetland Indicator Status is Facultative (FAC) for the Midwest.

Conservation status: Global- G5, secure; Nebraska- S1, critically imperiled (NatureServe) 

General Comments

Narrowleaf mountainmint, like other members of the genus Pycnanthemum, is visited by numerous and diverse pollinators including native bees, wasps, and flies. This species can be distinguished from the other members of the genus in Iowa by its hairless stems, narrower leaves (not exceeding 1/4 in), brown seed heads (not gray), and somewhat later flowering time. Plants are relatively easy to grow, yield heavily for a few years, and produce seed that stores well under refrigeration.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Not recommended for this species.

 

‌‌Greenhouse

Seed pre-treatment: Dry/cold stratify 12 weeks at 40° F.

Sowing: Surface sow seed in greenhouse two months before last frost free date.  Water carefully (fine mist) to prevent seed from splattering out of containers.

Transplanting: Transplant into a weed barrier at 8-12 in intervals.  Plants spread clonally, so the weed barrier can be removed by the third season, but seed production typically declines by the fourth season.

‌Appendix A

Stand management

Weeds: Plastic mulch or weed barrier suppresses many weeds during the first year or two. Hand rogue weeds, being careful not to uproot seedlings or disturb roots and rhizomes of the mountainmint. An anecdotal report from a commercial native seed grower suggests that cultivation within mountainmint rows weakens plants and can cause loss of the crop.

Pests: None noted.

Diseases: None noted.

Seed production

First harvest: Some flowering and seed production first year from greenhouse grown transplants.

Yield: 10-80 bulk pounds/acre

Stand life: Peak harvests second-third year. Stand persists but seed production may decline significantly fourth year and after.

Flowering date: Flowering occurs mid-July into August.

Seed maturity/Harvest date: Mid September to early October.

Seed retention: Holds seed well, shattering occurs mid to late October.

Harvest date range at TPC (2004-2007): Sept 21 - Oct 18

Recommended harvest method: Combine, no air. 

Appendix B

Seed cleaning and storage

Cleaning process: Pre-clean by scalping thru 1/2 in and 1/4 in mesh to remove large particles and make flowable, then air-screen. (No awns or appendages to remove).

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone 3 (southern Iowa)

References

Gleason, H. A., & Cronquist, A. (1991). Lamiaceae. In Manual of Vascular Plants of Northeastern United States and Adjacent Canada (2nd ed., p. 443). The New York Botanical Garden. 

Hilty, J. (2019). Slender mountain mint - Pycnanthemum tenuifolium. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/slm_mintx.htm 

Houseal, G. A. (2007). Forbs Wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 44–45). Tallgrass Prairie Center - University of Northern Iowa.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

USDA NRCS National Plant Data Team. (n.d.). Pycnanthemum tenuifolium Schrad. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=PYTE

Species Guide Updated 12/5/2025

Echinacea pallida (Nutt.) Nutt. 

Alternate Common Names: prairie coneflower, pale echinacea

Scientific Synonyms: Brauneria pallida (Nutt.) Britton, Rudbeckia pallida Nutt.

Family: ‌aster family (Asteraceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial from a stout taproot.

Height: 2-3 ft  

Leaves and stem

‌

Leaves mostly basal, long tapered, coarsely hairy with three prominent parallel veins; stems grayish to reddish green, covered in coarse hairs, unbranched.

Flower, fruit and seedhead

Flower: Single composite flower head at top of stem with 7 or more pink-purple (sometimes white), slender, drooping ray florets and a prominent central cone. Pollen is white.

Fruit/seedhead: Seed head is a dark brown-black cone, about 1 inch in diameter. Seeds (achenes) develop from disk flowers, which bloom from the outer ring of the cone inwards.

Pollination: Insects, primarily bees and butterflies.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 5,200 (IA NRCS) 

Seeds per pound: 83,200 (IA NRCS)

1000 seed weight: 5.66 g (Seed Information Database)

Description: The “seed unit” is a dry fruit called an achene, about 1/8 in long, with a dark brown band at the square end and pale gray from there to the pointed end. No awns or appendages to remove.

Typical seed test 

PLS: 96% (n = 10)

Purity: 99% (n = 10)

Germination: 44% (n = 9)

Dormant: 52% (n = 9)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Dry-mesic to mesic soil; prefers sites with well-drained upland soils and full sun; prairies, oak savannas, abandoned fields, dry woodland openings, along railroads. Avoid wet or poorly drained soils for seed production.

Conservation status: Global- G4, apparently secure; Georgia, Nebraska, North Carolina, and Tennessee- S1, critically imperiled; Alabama- S2, imperiled; Wisconsin- S3, vulnerable (NatureServe)

General Comments

This species is best propagated in the greenhouse and transplanted into a weed barrier or bare soil. Weed suppression is essential for good establishment and seed production. Combine harvest is fairly straightforward, since it retains seed well in the heads. All Echinacea species are known to hybridize, so proper isolation should be maintained between related species to prevent hybrid seed production (McGregor 1968).

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Row spacing: 30-36 in rows

PLS pounds/acre: 3.0-5.0

Seeds per linear foot: 40

Seeding depth: 1/8 in

Seeding method: native seed drill

Seeding time: dormant season

Weed control: Prepare clean, firm, weed free seedbed prior to seeding.

 

‌‌Greenhouse

Seed pre-treatment: Wet stratify 12 weeks at 40° F.

Sowing: Sow seed surface to 1/8 in deep in the greenhouse two months before last frost free date. Literature suggests this species needs light to germinate, but covering seed lightly to 1/8 in does not inhibit germination.

Transplanting: When root growth is sufficient to produce a sturdy plug, harden off, then transplant into bare soil in rows or weed barrier at 8-12 in intervals after all danger of frost.

‌Appendix A

Stand management

Weeds: Planting into a weed barrier or plastic mulch suppresses weeds in the first growing season; hand rogue weeds, being careful not to uproot seedlings.

Pests: None noted.

Diseases: None noted.

Hybridization risk: Echinacea angustifolia, E. purpurea

Seed production

First harvest: Second year plants.

Yield: 55-210 bulk pounds/acre (yields extrapolated from harvests of 6 plots)

Stand life: Peak harvests second year. Good harvest third year. Stand persists, but seed production declines significantly fourth year and after.

Flowering date: mid-June to mid-July in northern Iowa

Seed maturity/Harvest date: September in northern Iowa

Seed retention: Generally holds seed well, some shattering may begin in late September and extend throughout the winter months.

Harvest date range at TPC (2003-2021): Aug 5 - Oct 25

Recommended harvest method: Combine before significant shattering occurs. 

Appendix B

Seed cleaning and storage

Cleaning process: Combine does a superb job of threshing seedheads. Pre-clean combined material by scalping through 1/2 in and 1/4 in mesh to remove large particles and make flowable, then air-screen. If hand harvested, seedheads need to be threshed using a hammermill or brush machine, using care not to overclean and damage the hulls of the achenes.

Seed storage: Cool/dry (33-50° F, 30-50% RH).

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Project Zones 1, 2, and 3; Northern Missouri Germplasm, Western Missouri Germplasm

References

Chayka, K. (n.d.). Echinacea pallida (pale purple coneflower). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/pale-purple-coneflower 

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Purple coneflowers. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 74–75). University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). Pale purple coneflower - Echinacea pallida. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/pale_coneflowerx.ht…;

Houseal, G. A. (2007). Forbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 32–33). Tallgrass Prairie Center - University of Northern Iowa.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

USDA NRCS National Plant Data Team. (n.d.). Echinacea pallida (Nutt.) Nutt. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=ECPA

Species Guide Updated 12/3/2024

Doellingeria umbellata (Mill.) Nees 

Alternate Common Names: flat-top aster, parasol aster, tall flat-topped white aster

Scientific Synonyms: Aster umbellatus Miller, Diplopappus umbellatus (Miller) Hooker, Diplostephium umbellatum (Miller) Cassini

Family: ‌aster or sunflower family (Asteraceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Long-lived perennial, spreads by short rhizomes to form small colonies.

Height: 1-5 ft

 

Leaves and stem

Lance-shaped, 3-5 in long and 1/2-1 in wide, leaf margins toothless, leaf surfaces usually hairless or with short hairs, alternate arrangement; stems are erect and unbranched except within the flower head, with few to no hairs, generally light yellowish-green but sometimes purple.

 

Flower, fruit and seedhead

Flower: Individual heads are daisy-like, about 1/2 in wide, with yellow to tan centers and usually 5-10 (up to 15) white “petals” (rays) irregularly arranged around the central disc; dozens to hundreds of heads in a branched, flattened cluster up to 10 or 12 in wide.

Fruit/seedhead: Seed head appears fuzzy due to creamy-white fluff (pappus) on seeds.

Pollination: Insects, including bees, butterflies, and moths

 

Seed

Appendix D

‌Seed characteristics 

Seeds per ounce: 67,000  (IA NRCS)

1000 seed weight: 0.7 g (Seed Information Database)

Description: Seed (achene) is light brown, 2.5-3 mm long, approximately 1 mm wide near the top, tapered to a point on the lower end, and bears a “parachute” of creamy white fluff (pappus).

Typical seed test 

PLS: 85% (n = 5)

Purity: 90% (n = 5)

Germination: 22% (n = 4)

Dormant: 71% (n = 4)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Moist to wet soils, preferably with some sand; partial to full sun; wet prairies, sedge meadows, seasonally wet ditches, and fens; benefits from irrigation in production systems. The USDA classifies it as a Facultative Wetland species in the Midwest region.

Conservation status: Global- G5, secure; Delaware, Iowa, and North Carolina- S3, vulnerable (NatureServe) 

‌

General Comments

Parasol whitetop is a late season nectar and pollen source for diverse species of bees (including specialist bees), wasps, beetles, flower flies, and skipper butterflies. It is a larval host to some species of checkerspot and crescent butterflies. It can grow and flower for many years in mesic soils but benefits from irrigation in production systems.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience with direct seeding this species for seed production.

‌‌Greenhouse

Seed pre-treatment: 60 days cold-moist stratification results in uniform and high rates of germination.

Sowing: Seed is small and should be only lightly covered with growing media. If started in germination flats, transplant to individual plugs when seedlings have their first pair of true leaves, about 2 weeks after seeding.

Transplanting: Seedlings are ready to transplant to the field about 6-8 weeks after transferring them to plugs, when their roots are well-branched and numerous root tips are visible at hole(s) in the base of the plug. Pop out a few plugs to check for adequate root development that will provide sturdy plugs for planting. Seedlings are fast growing and may need to be clipped back before transplanting to improve the shoot:root ratio. A week or two before transplanting, move flats outside to ‘harden off.’ (See Propagation chapter in General Information for more details).

‌Appendix A

Stand management

Weeds: In the first season after transplanting, weeds are suppressed by a plastic weed barrier. Plants spread slowly by short rhizomes; in second and subsequent years, holes in plastic may need to be expanded or plastic removed to make room for new stems.

Pests: None noted.

Diseases: None noted.

Soil moisture: This species benefits from drip irrigation when planted in mesic soils.

Seed production

First harvest: Plants will flower and produce a small amount of seed in the planting year when started from transplants.

Yield: 28-74 pounds/acre (based on 1 plot)

Stand life: unknown

Flowering date: August - September

Seed maturity/Harvest date: late September - late October

 

Seed retention:  Seeds are wind dispersed soon after maturity, when fluff (pappus) expands in late September through October.

Harvest date range at TPC (2022-2023): Sept 15 - Oct 20

Recommended harvest method: Seed is released from heads within days of the fluffy “parachutes” expanding. Watch for the centers of seed clusters to begin shattering, and pick early maturing seed heads (clip stalks below seed clusters). If some heads in a cluster are still closed (not fluffy), pull apart a few heads to see if the seeds are dark colored and separate easily from the base (receptacle). Combine the rest of the plot at peak maturity. Turn off air or combine will disperse the fluffy seeds.

Appendix B

Seed cleaning and storage

Cleaning process: If hand clipped, run dried material through a 1/4 in mesh to thresh seed from stalks. Use a brush machine (medium bristles, low vacuum) to remove pappus. May need two rounds of brushing. Winnow with a box fan to separate seed from most of the pappus and chaff. Airscreen 2-3 times, then indent to remove broken bits of stems. See Appendix C for specific settings.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone NI

References

Chayka, K. (n.d.). Doellingeria umbellata (flat-topped white aster). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/flat-topped-white-aster 

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Flat-top aster. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 133). University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). Flat-topped aster - Doellingeria umbellata. Illinois Wildflowers. https://www.illinoiswildflowers.info/wetland/plants/fltp_aster.html

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 28, 2024).

Society for Ecological Restoration, International Network for Seed Based Restoration and Royal Botanic Gardens Kew. (2023) Seed Information Database (SID). Available from: https://ser-sid.org/ (February 2023)

USDA NRCS National Plant Data Team. (n.d.). Doellingeria umbellata (Mill.) Nees. USDA plants database. https://plants.usda.gov/plant-profile/DOUM2

Van Der Grinten, Martin. (2001). Propagation protocol for production of Container (plug) Aster umbellatus P. Mill. plants USDA NRCS - Big Flats Plant Materials Center Corning, New York. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2024/02/02). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.

Semple, J. C., & Chmielewski, J. G. (2020, November 6). Doellingeria umbellata (Miller) Nees. Flora of North America. http://floranorthamerica.org/Doellingeria_umbellata

Species Guide Updated 12/20/2024

Ratibida pinnata (Vent.) Barnhart 

Alternate Common Names: gray-headed coneflower, yellow coneflower, globular coneflower, drooping coneflower, gray coneflower, prairie coneflower, weary susan, grayhead coneflower, drooping yellow coneflower

Scientific Synonyms: Lepachys pinnata (Vent.) Torr. & A. Gray, Rudbeckia pinnata Vent.

Family: ‌aster family (Asteraceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial that forms tight clumps or colonies.

Height: 3-7 ft  

Leaves and stem

Leaves are alternate, irregular in shape and pinnately divided into 3-7 lobes, with short, rough hairs; stems are long, stiff, and slender, unbranched except near the top.

Flower, fruit and seedhead

Flower: Composite flower heads borne singly at the tips of long stalks with drooping 1 in long yellow petals (rays) surrounding the egg-shaped dome of disk flowers.

Fruit/seed head: Firm, dense seedheads often hold some seed into late fall and winter and release an anise or citrus scent when crushed. 

Pollination: Insects including bees, butterflies, flies, wasps, and beetles.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 30,000 (IA NRCS)

1000 seed weight: 0.87 g (Seed Information Database)

Description: Seeds (achenes) develop from fertile disc flowers. Achenes are brown to black and about 1/16 in long.

Typical seed test 

PLS: 93% 

Purity: 99%

Germination: 76%

Dormant: 8%

(averages obtained from 11 tests of purchased seed lots)

Habitat and range

‌Habitat: Wet-mesic to dry-mesic loamy soils; full sun; usually common on medium to high quality prairies; remnant prairies, thickets, woodland edges, prairies, limestone glades.

Conservation status: Global- G5, secure; West Virginia- SH, possibly extirpated; Pennsylvania and South Carolina- S1, critically imperiled; Florida and Louisiana- S2, imperiled (NatureServe) 

General Comments

Pinnate prairie coneflower is typically common on Midwestern prairies and establishes readily from seed in reconstructed prairies. Some seeds generally stay in the seedheads through fall and into winter are eaten by songbirds. Seed harvesting and cleaning are relatively straightforward if good weed control is maintained.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Row spacing: 30-36 in rows

PLS pounds/acre: 3.6-5.0

Seeds per linear foot: 40

Seeding depth: 1/4 in 

Seeding method: native seed drill

Seeding time: dormant season

Weed control: Prepare clean, firm, weed free seedbed prior to seeding.

 

‌‌Greenhouse

Seed pre-treatment: Wet stratify 8-12 weeks at 40° F. 

Sowing: Sow seed in greenhouse two months before last frost free date.

Transplanting: Harden-off, transplant into bare soil in rows or weed barrier at 8-12 in intervals after all danger of frost.

‌Appendix A

Stand management

Weeds: Mow/cultivate between rows. Post emergence grass herbicide, tillage, roguing.

Pests: None noted.

Diseases: None noted.

Seed production

First harvest: Remain vegetative the first year, abundant flowering and seed production second year.

Yield: 100-250 bulk pounds/acre

Stand life: Peak harvests second year. Good harvest third year. Stand persists but seed production may decline significantly fourth year and after.

Flowering date: Flowering occurs early July to mid-August.

Seed maturity/Harvest date: Late September

Seed retention: Shattering occurs mid to late October.

Harvest date range at TPC (2004-2010): Sept 3 - Oct 27

Recommended harvest method: combine 

Appendix B

Seed cleaning and storage

Cleaning process: Pre-clean by scalping through 1/2 in and 1/4 in mesh to remove large particles and make flowable, then air-screen. Foxtail can be removed from most of the seed with scalping screens, followed by a final cleaning with a belt-sorter or velvet roller of scalped material. (Brushing is not needed as there are no awns or appendages to remove).

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Project Zones 1 (northern Iowa), 2 (central Iowa), and 3 (southern Iowa); Northern Missouri Germplasm

Cultivated variety (cultivars): Sunglow (KS)

References

Chayka, K. (n.d.). Ratibida pinnata (gray-headed coneflower). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/gray-headed-coneflower  

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Yellow coneflower. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 105). University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). Yellow coneflower - Ratibida pinnata. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/yl_coneflowerx.htm  

Houseal, G. A. (2007). Forbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 48–49). Tallgrass Prairie Center - University of Northern Iowa.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

Runkel, S. T., & Roosa, D. M. (2009). Yellow coneflower. In Wildflowers of the tallgrass prairie: The upper Midwest (2nd ed., pp. 154–155). University of Iowa Press.

USDA NRCS National Plant Data Team. (n.d.). Ratibida pinnata (Vent.) Barnhart. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=RAPI

Species Guide Updated 12/5/2025

Liatris pycnostachya Michx. 

Alternate Common Names: cat-tail gayfeather, thick-spike gayfeather, prairie blazingstar, prairie blazing-star, button snakeroot, gayfeather, blazing star, thick-spike gay-feather, thick-spike blazing-star

Scientific Synonyms: Lacinaria pycnostachya (Mich.) Kuntze

Family: ‌aster family (Asteraceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial from corms that can be divided.

Height: 2-5 ft  

Leaves and stem

Leaves grasslike, alternate but so crowded as to appear almost whorled, becoming progressively shorter toward the top of the stem; stem is hairy and stiff, unbranched.

Flower, fruit and seedhead

Flower: Heads of 5-10 purplish-pink disk flowers with long styles that stick out; slender heads are densely packed in spikes that bloom from the top down.

Fruit/seedhead: “Seed” is an achene bearing a tan pappus (tuft of hair), distributed by the wind.

Pollination: Insects such as butterflies, bees, and moths.

Seed

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 11,000 (IA NRCS)

1000 seed weight: 1.86 g (Seed Information Database)

Description: “Seeds” are achenes, about 1/8 to 1/4 in long, with tufts of tan hairs (pappus).

Typical seed test 

PLS: 93% (n = 10)

Purity: 98% (n = 10)

Germination: 22% (n = 7)

Dormancy: 73% (n = 6)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Mesic to wet-mesic soils; full sun; may be abundant in medium to high quality prairies; moist meadows, rocky bluffs, along railroads, limestone glades. Wetland Indicator Status is Facultative (FAC) for the Midwest. Moist, but well-drained soils are preferred for seed production.

Conservation status: Global- G5, secure; Indiana and South Dakota- S1, critically imperiled; (NatureServe)

General Comments

Prairie blazing star is best propagated in the greenhouse, where seedlings form small pea-sized corms after about 2 months. First true leaves of seedlings are grass-like. Expect prolific seed production in the second growing season, after which the stand declines. Corms can be dug and divided for fall transplant, if disease free, for abundant flowering and seed set the following growing season. Species in the genus Liatris are known to hybridize, therefore proper isolation should be maintained between related species to avoid hybrid seed production (Levin 1968, Menhusen 1972). Liatris species and cultivars are also produced commercially for the landscaping and cut-flower industries.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Not recommended for this species

 

‌‌Greenhouse

Seed pre-treatment: Wet stratify 8-12 weeks at 40˚ F. Seed may be prone to mold in stratification. Some growers add fungicide to the stratification media.

Sowing: Sow seed in greenhouse two months before last frost free date.

Transplanting: Harden-off, transplant into bare soil in rows or weed barrier at 8 in intervals after all danger of frost.

‌Appendix A

Stand management

Weeds: Mow/cultivate between rows, mulch within rows. Post emergence grass herbicide, tillage, hoeing, hand roguing. Very sensitive to soil disturbance during bolting/flowering, so clip weeds rather than pulling or hoeing after flowering shoots emerge.

Pests: Voles will eat and/or cache corms, rabbits and deer eat young shoots, goldfinches eat seed as it matures.

Diseases: powdery mildew, root-knot nematodes, stem rot, verticillium wilt.

Hybridization risk: This species is known to hybridize with related species Liatris acidota, L. ligulistylis, L. punctata, and L. squarrosa

Seed production

First Harvest: Plants remain vegetative for the first year (seedlings); abundant flowering/seed production second year. Fall corm division/transplanting results in abundant flowering the following growing season.

Yield: 11-307 pounds/acre (per acre yields extrapolated from harvest records of 4 plots)

Stand life: Peak harvests occur in the second year. Good harvest third year if proper soils. Stand declines significantly fourth year and after. Plants tend to lodge second year when flowering. On more well-drained soils, irrigation may improve yields.

Flowering date: late July - late August in northern Iowa

Seed maturity/Harvest date: early September - mid-October in northern Iowa

Seed retention: Seed is wind dispersed shortly after ripening when pappus “parachutes” dry and fluff out

Harvest date range at TPC (2003-2023): Sept 2 - Oct 23

Recommended Harvest Method: Combine at maturity, but before pappus is dry and fluffy. Seedheads mature from the top down along a stalk. When the topmost heads are fluffy, break open a few of the lower heads and observe for signs of maturity: dark-colored seeds that separate easily from the base of the head. Small plots may be hand harvested by clipping stalks as the seed matures, then drying the cut material in a building. Dry seed threshes easily from stalks.

Appendix B

Seed cleaning and storage

Cleaning process: Pre-clean by scalping thru 1/2 in mesh to remove large particles and make the material flowable, brush gently with soft bristles to remove fluffy pappus, using care not to damage seed coat, then air screen.

Seed storage: cool/dry (33-50° F, 30-50% RH); seed stores well for a few years if seed is not damaged during cleaning.

Appendix C

Released Germplasm 

Source Identified material: Northern Iowa Germplasm (IA Zone 1), Central Iowa Germplasm (IA Zone 2), Southern Iowa Germplasm (IA Zone 3), Northern Missouri Germplasm, Western Missouri Germplasm

Selected Germplasm: Pineywoods Germplasm (TX)

Cultivated variety (cultivars): Eureka (KS; developed for cut flower industry)

References

Chayka, K. (n.d.). Liatris pycnostachya (prairie blazing star). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/prairie-blazing-star 

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Thick-spike gay-feather. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 98). University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). Prairie blazingstar - Liatris pycnostachya. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/pr_blazingstarx.htm 

Houseal, G. A. (2007). GForbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 40–41). Tallgrass Prairie Center - University of Northern Iowa.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

Levin, D.A. (1968). The Structure of a Polyspecies Hybrid Swarm in Liatris. Evolution, 22(2), 352-372. https://doi.org/10.1111/j.1558-5646.1968.tb05903.x 

Menhusen, B.R. (1972). Ecology of the Prairie Species of the Genus Liatris. Third Midwest Prairie Conference Proceedings. Manhattan, Kan.: Division of Biology, Kansas State University. https://search.library.wisc.edu/digital/AL7JMUVRYYXDZO8S/pages/A56MVY3FXXELEL8L  

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February  29, 2024).

Nesom, G. L. (2020, November 6). Liatris pycnostachya Michaux. Flora of North America. http://floranorthamerica.org/Liatris_pycnostachya 

Runkel, S. T., & Roosa, D. M. (2009). Blazing star. In Wildflowers of the tallgrass prairie: The upper Midwest (2nd ed., pp. 198–199). University of Iowa Press.

USDA NRCS National Plant Data Team. (n.d.). Liatris pycnostachya Michx. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=LIPY

Species Guide Updated 2/21/2025

Heliopsis helianthoides (L.) Sweet

Alternate Common Names: common ox-eye, false sunflower, sunflower heliopsis, ox-eye, sunflower-everlasting

Scientific Synonym: Buphthalmum helianthoides L.

Family: ‌aster family (Asteraceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial, fibrous rooted, producing clumps or colonies from rhizomes.

Height: 2-6 ft

Leaves and stem

Leaves opposite, egg-shaped with pointed tips, saw-tooth margins, rough texture, up to 5 in long and 3.5 in wide; stem is erect, rough with short hairs, branched.

Flower, fruit and seedhead

Flower: One to 15 sunflower-like yellow flower heads, 1.5-3 in (4-7.5 cm) in diameter, at ends of long stalks from stem tip and upper leaf axils; ray florets are yellow-orange color, center disk usually golden yellow; underside of the flower head with alternating short and long bracts (phyllaries).

Fruit/seedhead: Flower head matures to a head of “seed” (achenes); achenes are dark, 3-4 angled, 4-5 mm long, and lack pappus; both disk and ray florets are fertile and produce achenes.

Pollination: Insects such as bees, wasps, beetles, flies, and butterflies.

Seed

Appendix D

‌Seed characteristics 

Seeds per ounce: 6,300 (IA NRCS)

Seeds per pound: 100,800 (IA NRCS)

1000 seed weight: 4.15 g (Seed Information Database)

Description: Seed unit is a smooth, dark achene about 3/16 in (4-5 mm) long.

Typical seed test 

PLS: 95% (n = 10) 

Purity: 100% (n = 10)

Germination: 65% (n = 9)

Dormant: 31% (n = 9)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Dry-mesic to wet-mesic soil; full sun; low to high quality remnant prairies, disturbed areas, roadsides, railroads, woodland openings and edges, thickets, streambanks, limestone glades. Wetland Indicator Status is Facultative Upland (FACU) for the Midwest.

Conservation status: Global- G5, secure; Delaware- S1, critically imperiled; Louisiana- S3, vulnerable (NatureServe)

‌

General Comments

Smooth oxeye is a component of most tallgrass prairies with medium to dry soils where it grows in association with tall, warm-season grasses. The long flowering time and abundant nectar and pollen make this an important pollinator resource, and the nutritious seeds are eaten by birds and mammals. This species is fairly easy to establish by direct seeding, if good seedbed preparation and weed suppression are achieved. Extended flowering and seed-ripening period makes determining optimal combine harvesting time difficult. Seed cleaning is accomplished with air-screen cleaning.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Row spacing: 30-36 in rows

PLS pounds/acre:  4.0

Seeds per linear foot: 40

Seeding depth: 1/4 in

Seeding method: native seed drill

Seeding time: dormant season

Weed control: Prepare clean, firm, weed free seedbed prior to seeding.

‌‌Greenhouse

Seed pre-treatment: Wet stratify 8-12 weeks at 40° F.

Sowing: Sow seed at 1/4 in depth about two months before the last frost-free date.

Transplanting: Harden off, transplant into bare soil in rows or weed barrier at 8 in intervals after all danger of frost. Since this species spreads by rhizomes to form clumps, remove weed barrier after establishment year or use biodegradable barrier.

‌Appendix A

Stand management

Weeds: Mow/cultivate between rows. Post emergence grass herbicide, tillage, roguing.

Pests: Plants may be affected by red aphids (Uroleucon) though these infestations are often cleared by parasitic wasps and aphid predators, and it is not clear that they cause much harm to the plants.

Diseases: Powdery mildew.

Seed production

First harvest: Some flowering and seed production in first growing season from transplants and in well-managed direct seeded stands.

Yield: 20-115 pounds/acre (per acre yield extrapolated based on production from 1 plot)

Stand life: Peak harvest second-fourth year with declining yields in subsequent years.

Flowering date: early June - late July in northern Iowa

Seed maturity/Harvest date: mid-August to late September in northern Iowa; complicated by long flowering and seed ripening period.

Seed retention: Shattering occurs mid to late October.

Harvest date range at TPC (2005-2008): Sept 15 - 21

Recommended harvest method: Combine

Appendix B

Seed cleaning and storage

Cleaning process: Pre-clean by scalping through 1/2 in and 1/4 in mesh to remove large plant matter and make flowable, then air-screen. (No awns or appendages to remove.)

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Central Iowa Germplasm (IA Zone 2), Northern Iowa Germplasm (IA Zone 1), Southern Iowa Germplasm (IA Zone 3)

Cultivated variety (cultivar): Midas (KS)

References

Chayka, K. (n.d.). Heliopsis helianthoides (smooth oxeye). Minnesota Wildflowers. https://minnesotawildflowers.info/flower/smooth-oxeye

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Ox-eye. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 88). University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). False sunflower - Heliopsis helianthoides. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/fs_sunflowerx.htm  

Houseal, G. A. (2007). Forbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 36–37). Tallgrass Prairie Center - University of Northern Iowa.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

Runkel, S. T., & Roosa, D. M. (2009). Ox-eye. In Wildflowers of the tallgrass prairie: The upper Midwest (2nd ed., pp. 162–163). University of Iowa Press.

Smith, A. R. (2020, November 6). Heliopsis helianthoides (Linnaeus) Sweet. Flora of North America. http://floranorthamerica.org/Heliopsis_helianthoides 

USDA NRCS National Plant Data Team. (n.d.). Heliopsis helianthoides (L.) Sweet. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=HEHE5 

Species Guide Updated 12/11/2024

Monarda punctata, L. 

Alternate Common Names: dotted horsemint, spotted horsemint, dotted monarda, dotted beebalm

Family: ‌mint family (Lamiaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Short-lived perennial, spreading by rhizomes to form clumps with a bushy appearance.

Height: 1-3 ft  

Leaves and stem

Leaves opposite, lance-shaped to narrowly lanceolate, 1-3 in long by 1/4 to 1/2 in wide, softly hairy; stems are brown to purple, 4-angled and branched sparingly, appearing frosted due to their coat of short, dense hairs.

Flower, fruit and seedhead

Flower: Whorls of flowers form an interrupted spike at the end of branching stems, with showy, white to lavender-pink, leaf-like bracts at the base of each whorl that persist even after the flowers themselves wither; flowers are up to 1 in long, yellow with purple spots, tubular in shape with a distinct upper and lower lip.

Fruit/seed head: Calyx tubes (fused sepals of the flowers) persist as whorls around stem nodes after leaves drop; multiple whorls of seedheads per stem help distinguish this species from its congener M. fistulosa in seed; four nutlets develop within each calyx tube.

Pollination: Insects, especially solitary wasps.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 90,000 seeds/oz (IA NRCS)

1000 seed weight: 0.27g (Seed Information Database)

Description: “Seed unit” is a nutlet, oval in outline, smooth and brown, about 1-mm long.

Typical seed test 

PLS: 90% (n = 2)

Purity: 92% (n = 2)

Germination: 20% (n = 1)

Dormancy: 83% (n = 2)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Dry to mesic sandy soil; full sun; sand and hill prairies, sandy savannas, sand dunes, sandy fields; Wetland Indicator Status is Obligate Upland (UPL) for the Midwest; very well drained soils are recommended for seed production.

Conservation status: Global- G5, secure; Ohio, Pennsylvania, and Vermont- S1, critically imperiled; in all other states within its natural range, status is S4 (apparently secure) to S5 (secure) or unranked (NatureServe) 

‌

General Comments

Spotted beebalm is in the same genus as wild bergamot, M. fistulosa, but is found in habitats with sandy soils. Spotted beebalm differs from wild bergamot in having multiple whorls of flowers along a stem and white to lavender bracts beneath each flower cluster that are showier than the flowers themselves. Spotted beebalm has a long blooming season from mid to late summer, and remains showy after the flowers drop due to its persistent bracts. Its primary pollinators are solitary wasps such as great black wasps and golden digger wasps which drink nectar as adults but supply their young with insect prey. As wasps visit the flowers to sip nectar, the flowers’ stamens dust their thoraxes thickly with yellow pollen. When wasps are feeding at the flowers, they are not aggressive, and we have never been stung even when working among hundreds of plants (and their attendant wasps) in a plot. Spotted beebalm is short-lived in production plots but produces a lot of seed per plant and is relatively uncomplicated to manage, harvest, and clean.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience with direct seeding this species for seed production.

 

‌‌Greenhouse

Seed pre-treatment: Cold/moist stratification for 30 days may improve germination. Seed test reports suggest that a proportion of seeds may be dormant, though this is highly variable. Not using dormancy breaking procedures risks loss of dormancy-related genetic traits from production populations.

Sowing: Surface sow in the greenhouse about 2 months before the average date of last frost. Use caution when watering to avoid splashing seeds off the surface.

Transplanting: When plugs are well-rooted, move them outside to harden off, then transplant at 8-12 inch intervals into rows prepared with plastic mulch.

‌Appendix A

Stand management

Weeds: Prepare clean, weed-free beds. Use plastic mulch to suppress weeds during the first growing season. Remove the mulch at the end of the season to allow plants to form clumps and to prevent moisture buildup. Mow or cultivate between rows and hand weed or rogue to prevent small-seeded weeds from contaminating the seed lot.

Pests: None noted.

Diseases: None noted.

Seed production

First harvest: Plants flower and set seed in the establishment year (from transplants), reaching peak harvest in the second year. 

Yield/acre: 120-260 pounds per acre (extrapolated from harvests of two plots)

Stand life: Plots are productive for two to three years. Subsequent yield declines are due to plant mortality in this short-lived species.

Flowering date: early July to late August in northeast Iowa

Seed maturity/Harvest date: mid September to mid October

Seed retention: Fairly low risk of shattering, except during high wind events.

Harvest date range at TPC (2017-2019): September 10 - October 18

Recommended harvest method: Hand clip early maturing plants, then combine when plot is at peak maturity. 

Appendix B

Seed cleaning and storage

Cleaning process: Brush to release seed remaining in calyx tubes, then airscreen.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone 2 (central Iowa) and Zone 3 (southern Iowa)

References

Chayka, K. (n.d.). Monarda punctata (spotted horsemint). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/spotted-horsemint

Christiansen, P., & Muller, M. (1999). Lamiaceae. An Illustrated Guide to Iowa Prairie Plants. (p.122). University of Iowa Press.

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Dotted horsemint. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 219). University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). Spotted bee balm - Monarda punctata. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/sp_balm.htm

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

Missouri Botanical Garden. (n.d.). Monarda punctata. Missouri Botanical Garden - Plant Finder https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=281405   

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

USDA NRCS National Plant Data Team. (n.d.). Monarda punctata L. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=MOPU

Species Guide Updated 12/22/2025

Eutrochium maculatum (L.) E. E. Lamont

Alternate Common Names: purple boneset, spotted trumpetweed

Scientific Synonyms: Eupatoriadelphus maculatus (L.) R. M. King & H. Rob., Eupatorium maculatum L., Eupatorium purpureum  L. var. maculatum  (L.) Darl., Eupatorium purpureum subsp. maculatum (L.) Á. Löve & D. Löve, Eupatorium trifoliatum var. maculatum (L.) Farwell

Family: ‌aster or sunflower family (Asteraceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial, spreads slowly by rhizomes to form clumps.

Height: 2-10 ft (mostly 3-6 ft) 

 

Leaves and stem

Lance-shaped, up to 9 in long with serrated margins, whorled in groups of 4-5 (usually) at each node; unbranched stems purple to purple-spotted (the name ‘maculatum’ means spotted and refers to this trait).

 

Flower, fruit and seedhead

Flower: 3-5 small, indistinct florets per head, in flat-topped to domed inflorescences with dozens to hundreds of pink to purplish heads (rarely white); inflorescences appear fuzzy due to the long styles that stick out of the florets.

Fruit/seedhead: Seed clusters ripen from the center outward, becoming tan and fluffy as seed matures; seed is wind-dispersed and susceptible to shattering in windy weather.

Pollination: Insects, particularly bees and butterflies.

 

Seed

Appendix D

‌Seed characteristics 

Seeds per ounce: 95,000 (IA NRCS)

1000 seed weight: 0.28 g (Seed Information Database)

Description: Slender, charcoal-gray seeds about 3 mm long with a tuft of tan pappus.

Typical seed test 

PLS: 74% (n = 5)

Purity: 86% (n = 5)

Germination: 17% (n = 4)  

Dormant: 72% (n = 4)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Moist to wet soil; full sun; wet prairies, sedge meadows, fens, ditches, and other wet places. The USDA classifies it as an Obligate Wetland species in the Midwest region. It benefits from irrigation in production systems.

Conservation status: Global- G5, secure; Idaho and West Virginia- S1, critically imperiled; Montana- S1/S2, critically imperiled to imperiled; Arizona, Virginia, and Georgia- S2, imperiled; Wyoming- S3, vulnerable (NatureServe) 

General Comments

The sweet-scented flowerheads attract numerous and diverse pollinators including the endangered rusty patched bumble bee. We once identified seven species of butterflies along a 150 foot row of flowering spotted joe pye weed in one 15-minute observation. Traditional uses of this species by Native tribes include treatments for digestive, urinary, kidney, and women’s complaints and using the hollow stems as straws. The clumped stems and whorled leaves produce dense shade that excludes most weeds from a well-established plot. Irrigation is important for seed production.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience direct seeding this species for seed production.

‌‌Greenhouse

Seed pre-treatment: 60 days cold-moist stratification.

Sowing: Seed is small and should be surface sown or very lightly covered or seedlings will not have enough energy to emerge. If started in germination flats, transplant to individual plugs when seedlings have their first pair of true leaves.

Transplanting: Seedlings are ready to transplant to the field about 8-12 weeks after starting in plugs, when their roots are well-branched and numerous root tips are visible at hole(s) in the base of the plug. Pop out a few plugs to check for adequate root development that will provide sturdy plugs for planting. A week or two before transplanting, move flats outside to ‘harden off.’ (See Propagation chapter in General Information for more details).

‌Appendix A

Stand management

Weeds: In the first season after transplanting, weeds are suppressed by a plastic weed barrier. Plants spread by short rhizomes; in second and subsequent years, holes in plastic must be expanded or plastic removed to make room for new stems. Well-established plots shade out most weeds.

Pests: None noted.

Diseases: None noted.

Soil moisture: Irrigation is necessary in most soils to obtain maximum seed yield.

Seed production

First harvest: Plants flower and set a little seed the first year when transplanted in spring.

Yield: 29-226 pounds/acre (based on 1 plot)

Stand life: Peak seed production in years 3-5, but plants are long-lived and vigorous for many years.

Flowering date: late July - early September in northeast Iowa

Seed maturity/Harvest date: second to third week of September

Seed retention: Seeds are wind dispersed soon after maturity, when fluff (pappus) expands in late August through September.

Harvest date range at TPC (2016-2022): Aug 26 - Oct 3

Recommended harvest method: Watch for the centers of seed clusters to begin shattering, and pick early maturing seed heads (clip stalks below seed clusters). If some heads in a cluster are still closed (not fluffy), pull apart a few heads to see if the seeds are dark colored and separate easily from the base (receptacle). Combine the rest of the plot at peak maturity. Turn off air or combine will disperse the fluffy seeds.

Appendix B

Seed cleaning and storage

Cleaning process: If hand clipped, run dried material through a 1/4 in mesh to thresh seed from stalks. Use a brush machine (medium bristles, minimum vacuum) to remove pappus. Winnow with a box fan to separate seed from most of the pappus and chaff. Airscreen 2-3 times to finish cleaning. See Appendix C for specific settings.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone 1

Cultivated variety (cultivar): ‘Gateway’ is a compact cultivar used in landscaping.

References

Chayka, K. (n.d.). Eutrochium maculatum (spotted joe-pye weed). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/spotted-joe-pye-weed

Eutrochium maculatum. (2024). Prairie Moon Nursery. https://www.prairiemoon.com/eutrochium-maculatum-joe-pye-weed-prairie-moon-nursery.html

Hilty, J. (n.d.). Spotted joe-pye weed - Eutrochium maculatum. Illinois Wildflowers. https://www.illinoiswildflowers.info/wetland/plants/sp_joepye.htm 

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

Lamont, Eric E. (2020, November 6). Eutrochium maculatum (Linnaeus) E. E. Lamont. Flora of North America. http://floranorthamerica.org/Eutrochium_maculatum 

Missouri Botanical Garden. (n.d.). Eutrochium maculatum “Gateway.” Plant Finder. https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=302488&is

Moerman, D. (2003). Native American ethnobotany database. BRIT. http://naeb.brit.org/

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 28, 2024).

North Carolina State Extension (n.d.) Eutrochium maculatum. North Carolina Extension Gardener Plant Toolbox. https://plants.ces.ncsu.edu/plants/eutrochium-maculatum/

SER, INSR, RBGK, Seed Information Database (SID). (2023). Eupatorium maculatum. https://ser-sid.org/species/567dc915-c79f-4608-a9d6-e1351ee9a2cb 

USDA NRCS National Plant Data Team. (n.d.). Eutrochium maculatum (L.) E.E. Lamont. USDA plants database. https://plants.usda.gov/plant-profile/EUMA9

Species Guide Updated 12/19/2024

Oligoneuron rigidum (L.) Small

Alternate Common Names: rigid goldenrod, hard-leaved goldenrod, prairie goldenrod, stiff-leaved goldenrod

Scientific Synonyms: Aster rigidus (L.) Kuntze, Solidago rigida* L. 

*Solidago rigida is the accepted name in Minnesota and in the Flora of North America. The USDA Plants Database places this species in the genus Oligoneuron.

Family: ‌aster family (Asteraceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial from fibrous roots; several stems arise in a clump.

Height: 1-5 ft  

Leaves and stem

Leaves alternate, lower leaves long-stalked, upper leaves nearly clasping the stem, grayish green with short soft hairs; stem is finely hairy, unbranched.

Flower, fruit and seedhead

Flower: Yellow flower heads, larger than typical for goldenrods, borne in a branched flat-domed cluster at top of stem.

Fruit/seedhead: Seed heads are fluffy due to a tuft of white pappus on each achene, seeds dispersed by wind.

Pollination: Insects including bees, butterflies, wasps, and beetles.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 41,000 (IA NRCS)

1000 seed weight: 0.94 g (Seed Information Database)

Description: Seeds are technically achenes, glabrous, bone-white, about 1/16 in long with long white plumes (pappus).

Typical seed test 

PLS: 79% (n = 10)

Purity: 96% (n = 10)

Germination: 34% (n = 8)

Dormancy: 45% (n = 8)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Dry-mesic to wet-mesic soil; full sun; prairies, savannas, thickets, limestone glades, roadsides, railroads. Well-drained, loamy soils are preferred for seed production.

Conservation status: Global- G5, secure; District of Columbia- SX, presumably extirpated; Massachusetts- SH, possibly extirpated; Connecticut, Maryland, Pennsylvania, South Carolina, and West Virginia- S1, critically imperiled; New York and Virginia- S2, imperiled; Georgia and Wyoming- S3, vulnerable (NatureServe) 

General Comments

Stiff goldenrod establishes readily from direct seed or transplants, and will spread from short rhizomes to form clumps. The flowers of this species are highly attractive to bees and other pollinators, including migrating monarch butterflies. The seeds are eaten by songbirds and gamebirds. Fields of this species can be combined but it is critical to harvest before plumes are dry and fluffy.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Row spacing: 30-36 in rows

PLS pounds/acre: 1.0

Seeds per linear foot: 40

Seeding depth: 1/4 in

Seeding method: native seed drill

Seeding time: dormant season

Weed control: Prepare clean, firm, weed free seedbed prior to seeding.

 

‌‌Greenhouse

Seed pre-treatment: Wet stratify 8-12 weeks at 40˚ F. 

Sowing: Sow seed in greenhouse two months before last frost free date.

Transplanting: Transplant into bare soil in rows convenient for tillage equipment, or into weed barrier at 8-12 in intervals after all danger of frost is past.

‌Appendix A

Stand management

Weeds: Post emergence grass herbicide, tillage, hand roguing. If transplanted into weed barrier or plastic mulch, this provides some weed suppression.

Pests: None noted.

Diseases: Foliage may be affected by rust.

Seed production

First harvest: Flowering and seed set at end of second growing season from either greenhouse grown transplants or direct seeded, well-managed stand.

Yield: 100-250 bulk pounds/acre 

Stand life: Peak harvests in second to fifth growing season. Seed production declines in subsequent years.

Flowering date: mid-August - mid-September in northern Iowa

Seed maturity/Harvest date: October in northern Iowa

Seed retention: Seed is wind dispersed soon after drying of plumes (pappus).

Harvest date range at TPC (2003-2011): Oct 9 - 25

Recommended harvest method: Combine after seed maturity but before more than 10% of the seedheads have turned white and fluffy. Otherwise, combining will simply contribute to dispersal of the seed crop. Harvested material will have to be forced-air dried and turned carefully to prevent mold and decay. 

Appendix B

Seed cleaning and storage

Cleaning process: Pre-clean air-dried material by scalping thru 1/2 in and 1/4 in mesh to remove large particles.  Remove plumes (pappus) with a debearder or brush machine, then air-screen.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Project Zone 1 (Northern Iowa), Zone 2 (Central Iowa),and Zone 3 (Southern Iowa)

References

Chayka, K. (n.d.). Solidago rigida (stiff goldenrod). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/stiff-goldenrod 

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Stiff goldenrod. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 118). University of Wisconsin-Madison Arboretum.

Flora of North America. Solidago rigida Linnaeus. (n.d.). http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=242417297  .

Hilty, J. (2019). Stiff goldenrod - Oligoneuron rigidum. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/stf_goldenrodx.htm 

Houseal, G. A. (2007). Forbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 42–43). Tallgrass Prairie Center - University of Northern Iowa.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024). 

Runkel, S. T., & Roosa, D. M. (2009). Stiff goldenrod. In Wildflowers of the tallgrass prairie: The upper Midwest (2nd ed., pp. 242–243). University of Iowa Press.

Semple, J. C., & Cook, R. E. (2020, November 6). Solidago rigida Linnaeus. Flora of North America. http://floranorthamerica.org/Solidago_rigida 

USDA NRCS National Plant Data Team. (n.d.). Oligoneurin rigidum (L.) Small. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=OLRI

Species Guide Updated 12/4/2024

Pedicularis lanceolata Michx.

Alternate Common Name: swamp betony

Scientific Synonyms: Pedicularis auriculata Sm., Pedicularis pallida Nutt., Pedicularis virginica Poir.

Family: ‌broomrape family (Orobanchaceae)

Functional Group: forbs (wildflowers), hemiparasites

Description 

Life cycle and growth form

Fibrous-rooted perennial, hemiparasitic, connects to the root systems of neighboring plants through structures called haustoria to obtain mineral nutrients.

Height: 1 - 3 ft  

Leaves and stem

Leaves up to 4 in long with coarsely textured surface, “fernlike” margins, opposite arrangement; sturdy stems are short-hairy to hairless and sparingly branched.

Flower, fruit and seedhead

Flower: Cream colored flowers, about 1 in long, tubular and 2-lipped, with top lip that overhangs and curves over lower lip; arranged in dense spikes up to 4 in long.

Fruit/seedhead: A many-seeded capsule that splits open at maturity to release seeds.

Pollination: Primarily bumblebees; the flowers are twisted, and only larger-bodied bees that can learn to open the flowers are capable of accessing the pollen.

Seed

Appendix D

‌Seed characteristics 

Seeds per ounce: 44,000 (IA NRCS)

1000 seed weight: 0.57 g (measured at TPC using seed harvested from plots)

Description: Wrinkled, oval, brown seeds are winged along one side, approx. 1.5 by 2.5 mm with the wing; the shape is reminiscent of Chinese dumplings (pot stickers)

Typical seed test 

PLS: 87.5%

Purity: 94.3%

Germination: 2%

Dormant: 90.8%

(averages obtained from 6 tests)

Habitat and range

‌Habitat: Moist to wet soil; partial to full sun; wet sand prairies, fens, swamps, sandy ditches, shorelines; Wetland Indicator Status is Obligate Wetland (OBL) for the Midwest.

Conservation status: Global- G5, secure; Kentucky- SX, presumably extirpated; Delaware- SH, possibly extirpated; Arkansas, Georgia, Maryland, Massachusetts, and North Carolina- S1, critically imperiled; Pennsylvania and Tennessee- S1/S2, critically imperiled to imperiled; Connecticut and West Virginia- S2, imperiled; New York- S2/S3, imperiled to vulnerable; Nebraska, New Jersey, and Virginia- S3, vulnerable (NatureServe) 

General Comments

Swamp lousewort is a hemiparasitic plant. This species is capable of photosynthesis but taps into the root systems of neighboring plants to obtain some of the mineral nutrients it needs for growth. Hemiparasitic plants may reduce the competitive dominance of their hosts, thereby promoting greater diversity in their plant communities. Swamp lousewort likely uses sedges, grasses, and composites as hosts in its wetland or wet prairie habitats. To establish plugs for seed production, we seeded stratified seed of swamp lousewort into plugs of two sedge species that could co-occur with it in nature. The seedlings transplanted well into irrigated production rows and produced abundant seed in the second year. The flowers are visited by worker bumble bees that can learn to twist open the flowers to access the pollen.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Not recommended for this species.

 

‌‌Greenhouse

Seed pre-treatment: Benefits from 60-day cold/moist stratification. Check seed frequently in later weeks of stratification period as some seeds may germinate in the cold.

Sowing: Start sedge host plants about one month before the lousewort stratification period is over. Sow two-three lousewort seeds into a shallow slit or divot made near the base of a host sedge in a plug. For this species we used trays of 50-cell plugs that are 4 in deep. As sedge host plants grow, trim them as often as necessary to keep light available to the lousewort seedlings. We found that trimming was needed more often with Carex bebbii hosts than with C. hystericina.

Transplanting: Transplant into prepared plasticulture beds with drip tape irrigation after danger of frost is past and plugs are sturdy with well-developed root systems. Move trays outside to “harden off” a week or more before transplanting.

‌Appendix A

Stand management

Weeds: Plastic mulch suppresses weeds in the planting year, and dense growth of host sedges is competitive with many weeds. We mow between rows to further suppress weeds. Small seeded weeds such as amaranth and lambsquarters would be a concern for seed cleaning.

Pests: None noted.

Diseases: None noted.

Soil moisture: Irrigation is recommended. Drip tape can be installed at the same time the plastic mulch is laid.

Seed production

First harvest: A few plants flower and set seed in the planting year, but the first sizable harvest is in the year after transplanting.

Yield/acre: 260 lbs/acre (extrapolated from yield of one TPC production plot in the year after transplanting)

Stand life: Unknown at this time.

Flowering date: August - September in northeast Iowa

Seed maturity/Harvest date: mid-September to mid-October

Seed retention: Some seed is lost from open capsules, especially in high wind.

Harvest date range at TPC (2023-2024): September 7 - October 26

Recommended harvest method: We harvested the stems as the capsules matured, dried them, and passed them through the stationary combine. Combining in the field should also be effective, though some shattering may occur once capsules open.

Appendix B

Seed cleaning and storage

Cleaning process: Seed that has been threshed through a combine may be passed through a coarse screen (1/4 in mesh) to remove remaining stemmy material, then airscreened. Hand collected material may need to be run through a brush machine to break up capsules and release seed.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone NI 

Collection locations used in generating this ecotype are shown in the map below, overlaid on the Generalized Provisional Seed Transfer Zones of the US Forest Service.

References

Chayka, K. (n.d.). Pedicularis lanceolata (swamp lousewort). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/swamp-lousewort  

Dahlberg, L. (2022, February 3). Propagating Swamp Betony by Luke Dahlberg. Grassland Restoration Network. https://grasslandrestorationnetwork.org/2022/02/03/propagating-swamp-betony-by-luke-dahlberg/ 

Hilty, J. (2019). Swamp lousewort - Pedicularis lanceolata. Illinois Wildflowers. https://www.illinoiswildflowers.info/wetland/plants/sw_lousewort.htm 

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024). 

USDA-NRCS. (2022). Conservation cover native seeding calculator [Excel File]. Retrieved from https://bit.ly/IA_OTH_Conservation_Cover-Native_Seeding_Calculator_2022

USDA NRCS National Plant Data Team. (n.d.). Pedicularis lanceolata Michx. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=PELA2

Species Guide Updated 2/14/2025

Asclepias incarnata L. 

Alternate Common Names: rose milkweed, silkweed, water nerve root, white Indian hemp, swamp silkweed

Family: ‌dogbane family (Apocynaceae), formerly assigned to the milkweed family (Asclepiadaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial, weakly rhizomatous, forming small clones of several stems; root systems are more fibrous than other commonly cultivated milkweeds such as butterfly milkweed (e.g., A. tuberosa).

Height: 2-5 ft

‌

Leaves and stem

Leaves 3-6 in long, usually narrowly lanceolate with smooth, untoothed edges and sessile on the stem or short-stalked, opposite arrangement; stems mostly hairless, usually unbranched (occasionally branched above).

 

Flower, fruit and seedhead

Flower: Numerous, various shades of rose-pink with a pronounced fragrance similar to bubblegum, in domed clusters 2-3 in across; individual flowers five-parted, radially symmetrical, with a crown of five tubular hoods surrounding a central column, petals and sepals curved downward (typical milkweed flowers).

Fruit/seedhead: Pods (follicles) are 2-4 in long, smooth/waxy, and teardrop-shaped; follicles open along one side at maturity, revealing many shiny brown seeds each of which bears a flattened wing and a plume of soft, white floss.

Pollination: Pollination: Insects, particularly butterflies and bees.

Seed

Appendix D

‌Seed characteristics 

Seeds per ounce: 4,800 (IA NRCS)

1000 seed weight: 3.65 g (Seed Information Database)

Description: Dark brown, oval, surrounded by flattened ‘wing’ and tuft of soft hairs.

Typical seed test 

PLS: 89% (n = 11) 

Purity: 98% (n = 11)

Germination: 7% (n = 7)

Dormant: 58% (n = 7)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Moist to wet, neutral to slightly acidic soil; partial to full sun open floodplains, lakeshores, ditches, wet prairies. Wetland Indicator Status is Obligate Wetland (OBL) for the Midwest. Benefits from irrigation in production systems.

Conservation status: Global- G5, secure; Arizona, Mississippi, Montana, and Nevada- S1, critically imperiled; Arkansas, Idaho, and Louisiana- S2, imperiled; Wyoming- S2/S3 imperiled to vulnerable; Georgia- S3, vulnerable (NatureServe)

‌

General Comments

Swamp milkweed is a valuable addition to pollinator habitat plantings on wetter soils and a showy, mannerly milkweed for home landscaping. This species is an important host for caterpillars of the monarch butterfly which feed upon its leaves. The fragrant flowers attract and provide nectar for numerous pollinators including various species of butterflies, bees, wasps, and flies. The strong, silky stem fibers are used as nesting material by songbirds and have traditionally been used for spinning and weaving by Native peoples, giving rise to some of the alternate common names such as silkweed and white Indian hemp. Establishment from plugs is rapid, and seed can be harvested the first fall, but production stands are short-lived (2-3 years).

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience with direct seeding this species for seed production. 

‌‌Greenhouse

Seed pre-treatment: To break dormancy, use 30-60 days cold stratification (check frequently for early germination) or a 24-hour soak in 250 ppm gibberellic acid (GA-3).

Sowing: Seed directly into plugs (2-3 seeds per cell) or on germination flat and lightly cover with potting mix, or germinate between sheets of moistened paper toweling and move to individual plugs as radicles (seed roots) emerge from seeds; start seeds 8-10 weeks before the average frost-free date.

Transplanting: Move plug flats outdoors 1-2 weeks before transplanting to allow seedlings to adjust to ambient conditions; plant with 1 ft spacing in plastic mulch with drip irrigation.

‌Appendix A

Stand management

Weeds: Field preparation through repeated tillage and application of plastic mulch reduces weed issues; hand harvesting of pods as they mature results in very pure seed.

Pests: Non-native oleander aphids (Aphis nerii) can form dense infestations, reducing plant vigor and causing abortion of flowers or pods or, in extreme cases, death of the plant. Scout for these golden yellow aphids when plants are in bud, as it is easier to control small aphid infestations. Aphid predators (e.g., ladybug larvae, hoverfly larvae, and lacewing larvae) and aphid mummy wasps help reduce damage.  Use the least toxic treatment possible (e.g., horticultural oils or insecticidal soaps) to avoid harming aphid enemies and pollinators, as aphids often occur at the time plants are in flower. Native seed-feeding milkweed bug species (Oncopeltus fasciatus and Lygaeus kalmii) pierce pods and feed on seeds. Manually remove clusters of red-orange milkweed bug nymphs from pods. A small proportion of pods is ruined by larvae of native milkweed stem weevils (Rhyssomatus lineaticollis or R. annectans). These appear as grubs or pupae inside the cluster of seeds. Affected pods have a small entry hole on the side and often mature prematurely. Earlier in the growing season, red milkweed longhorn beetles (Tetraopes spp.) feed on the tips of milkweed leaves. Their larvae feed within milkweed roots and rhizomes and may weaken plants over time. Monarch butterflies (Danaus plexippus) are attracted to lay eggs on swamp milkweed. In smaller-scale production systems, caterpillars can be hand-picked from production rows and transferred to nearby wild milkweeds before applying treatments for problem insects.

Diseases: Milkweeds are susceptible to a variety of fungal, bacterial, and viral diseases. Cultural methods such as reducing stand size or density, intercropping, and crop rotations may reduce disease spread and severity.

 Hybridization risk: This species is known to hybridize with related species Asclepias hirtella, A. purpurascens, A. sullivantii, A, syriaca, A. tuberose, A. verticillata.

Soil moisture: Plant in naturally wet soils and/or supply irrigation, especially in dry weather.

Note: Refer to Milkweeds: A Conservation Practitioner’s Guide, published by the Xerces Society, for more detailed information on milkweed insects and diseases and their control.

Seed production

First harvest: Fall of planting year, when started from transplanted plugs.

Yield: 200-300 pounds/acre, with largest harvest in the first year (based on 4 plots)

Stand life: Two years from transplanting. Plants are reported to be longer lived in natural populations.

 

Flowering date: July in northern Iowa

Seed maturity/Harvest date:  Early September - mid-October in northern Iowa

Seed retention: Seed is released as individual pods ripen and split open in early September through the beginning of October.

Harvest date range at TPC (2009-2020): Aug 31 - Oct 17

Recommended harvest method: Harvest by hand as pods (follicles) mature; collect pods that are changing color from green to yellowish and split when subjected to gentle pressure on the suture (seam), revealing dark brown seeds.

Appendix B

Seed cleaning and storage

Cleaning process: Dry pods in cloth bags for two weeks with fan-forced air. Pass pods through a debearder or stationary combine to release seeds and detach fluff. Follow up by fan winnowing (outside on a relatively calm day) to remove most of the fluff. Air-screen the remaining material. Indent cylinder removes broken bits of pods and stems from seed.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source identified material: Natural Selections/Iowa Ecotype Zones 1, 2, IA

Cultivated variety (cultivar): ‘Ice Ballet,’ ‘Cinderella,’ and ‘Milkmaid’

References

Borders, B. and E. Lee-Mäder. 2014. Milkweeds: A Conservation Practitioner’s Guide. 143 pp. Portland, OR. The Xerces Society for Invertebrate Conservation. https://www.xerces.org/sites/default/files/2018-05/17-031_02_XercesSoc_Milkweeds-Conservation-Guide_web.pdf

Chayka, K. (2010). Asclepias incarnata (swamp milkweed). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/swamp-milkweed  

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Swamp milkweed. In Prairie plants of the University of Wisconsin, Madison Arboretum (3rd ed., p. 55). University of Wisconsin-Madison Arboretum. 

Hilty, J. (2020). Swamp milkweed - Asclepias incarnata. Illinois Wildflowers. https://www.illinoiswildflowers.info/wetland/plants/sw_milkweed.htm  

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

Kirk, S. and Belt, S. (2011). Plant fact sheet for swamp milkweed (Asclepias incarnata). USDA-Natural Resources Conservation Service, Norman A. Berg National Plant Materials Center. Beltsville, MD 20705. https://plants.usda.gov/DocumentLibrary/factsheet/pdf/fs_asin.pdf

  Native Plant Trust (2024). Asclepias incarnata. https://plantfinder.nativeplanttrust.org/plant/Asclepias-incarnata

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 28, 2024).

Runkel, S. T., & Roosa, D. M. (2009). Swamp milkweed. In Wildflowers of the tallgrass prairie: The upper Midwest (Second, p. 179). University of Iowa Press. 

Schultz, Jan; Beyer, Patty; Williams, Julie. (2001). Propagation protocol for production of Container (plug) Asclepias incarnata L. plants USDA FS - Hiawatha National Forest Marquette, Michigan. In: Native Plant Network. US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources. https://NativePlantNetwork.org (accessed 2024/01/09).

Society for Ecological Restoration and Royal Botanic Gardens Kew. (2024). Asclepias incarnata L. SWAMP MILKWEED. Seed Information Database. https://ser-sid.org/species/62fbef4e-ed33-4c71-a18f-f78f9018fda7 

University of Wisconsin. (2024). Common milkweed insects. Wisconsin Horticulture, Division of Extension. https://hort.extension.wisc.edu/articles/common-milkweed-insects/

Species Guide Updated 12/19/2024

Verbena hastata L.

Alternate Common Names: blue vervain, simpler’s joy, American blue vervain, American simpler’s joy, wild hyssop

Family: ‌verbena family (Verbenaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial, short-rhizomatous.

Height: 2-6 ft 

 

Leaves and stem

‌

Leaves are opposite, lance-shaped (up to 6 in long and 1 in wide), coarsely toothed, strongly veined above, and usually short-hairy beneath; stems square, grooved, and green to purple, with flattened hairs, often branched in the upper half of the plant.

Flower, fruit and seedhead

Flower: Individual flowers are blue-purple, 1/4 in across, with five expanded lobes (petals) attached to a short tube; flowers are arranged in a branched “candelabra” (panicle) of spikes; spikes elongate through the flowering season as new flowers emerge in whorls (rings) near the tops while seeds (nutlets) mature near their bases.

Fruit/seedhead: Each calyx of fused sepals contains four developing seeds (nutlets); spikes ripen from the bottom up.

Pollination: Insects, particularly bees.

Seed

Appendix D

‌Seed characteristics 

Seeds per ounce: 93,000 (IA NRCS)

1000 seed weight: 0.23 g (Seed Information Database)

Description: Seed unit is technically a type of dry fruit called a nutlet. Rust-brown nutlets are 2 mm long and approximately 0.5 mm wide.

Typical seed test 

PLS: 97%

Purity: 100%

Germination: 13%

Dormant: 84%

(averages obtained from 5 tests of purchased seed lots)

Habitat and range

‌Habitat: Swamp verbena grows best in full sun and moist to wet, organic-rich soils. Plants are typically found in wet places such as wet prairies, sedge meadows, fens, and ditches. Wetland Indicator Status is Facultative Wetland (FACW) for the Midwest. Production fields benefit from irrigation.

Conservation status: Global- G5, secure; North Carolina- S2/S3, imperiled to vulnerable; Wyoming- S3, vulnerable (NatureServe)

General Comments

Swamp verbena is well suited for planting in moist soils or seasonally wet sites such as roadside ditches. It grows quickly and flowers in the planting year, producing abundant seed that is relatively easy to harvest and clean. Most mammalian herbivores avoid the bitter foliage, hence this species has persisted even in heavily grazed, wet prairie pastures. Swamp verbena has a long flowering period and is visited by diverse species of bees and small butterflies. The seeds are eaten by native sparrows and juncos. Swamp verbena has numerous uses in traditional Native medicine, including as a treatment for digestive and obstetric complaints. Caution: Extracts of this species are known to interfere with prescription medication and can cause vomiting and diarrhea in high doses.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience direct seeding this species for seed production.

‌‌Greenhouse

Seed pre-treatment: Cold/moist stratification is recommended. Different sources suggest a minimum of 30 days (RNGR) up to 3 months (NRCS Plant Guide). Most northern Iowa accessions showed high rates of germination after 30 day stratification, but a few accessions appeared to have a higher degree of dormancy. In these cases, we saw a second flush of germination after a week of very high temperatures in the greenhouse, more than 2 months after sowing. 

Sowing: Sow seed on surface of germination mix (light needed for germination).

Transplanting: Seedlings grow rapidly with fibrous root systems that form firm plugs for transplanting. Plan on sowing seed in greenhouse containers 8-10 weeks before transplanting. If seedlings grow too tall in plug trays, they should be pinched back to adjust the shoot:root ratio.

‌Appendix A

Stand management

Weeds: Plastic mulch prevents weed competition in the first year, and tall fast-growing verbena plants are fairly competitive. Holes in the plastic may need to be widened to accommodate rhizomatous spread in the second and subsequent years. Focus weeding or roguing efforts on weeds that could contaminate the seed (i.e., species with small, elongated seed).

Pests: None noted. Bitter foliage deters mammalian herbivores.

Diseases: None noted, though plants appear to be short-lived (2-4 years) in production rows.

Hybridization risk: Maintain separation between fields of swamp verbena and other species in the genus Verbena (e.g., hoary vervain, Verbena stricta) as hybrids readily form. 

Soil moisture: Irrigation is recommended.

Seed production

First harvest: In planting year, when grown from transplants.

Yield: 440-610 pounds/acre (based on 2 plots)

Stand life: Estimated 3-4 years, with peak harvest in year one.

Flowering date: late June - September

 

Seed maturity/Harvest date: mid-September - mid-October

Seed retention: Shattering begins as seedheads turn from purple to brown in mid-September through mid-October.

Harvest date range at TPC (2021-2023): Sept 16 - Oct 19

Recommended harvest method: Seed heads turn from green to purple to brown as they mature. Harvest when all, or nearly all, parts of the spikes have turned brown. Some seeds will shatter from lower parts of spikes as the seeds in the upper parts mature, but most seed is retained on the plant. Hand harvest early maturing individuals to preserve genetic diversity, then combine the rest of the plot at peak maturity.

Appendix B

Seed cleaning and storage

Cleaning process

Hand-collected material: Dry on tarp or in a cloth bag for 2 weeks. Thresh by passing through a stationary combine or by stomping/beating material on the tarp or in a plastic tub. Pass through a ¼ in and ⅛ in mesh to remove sticks before airscreening.

Combined material: Hand-collected material: Dry on tarp or in a cloth bag for 2 weeks. Thresh by passing through a stationary combine or by stomping/beating material on the tarp or in a plastic tub. Pass through a 1/4 in and 1/8 in mesh to remove sticks before airscreening. 

Note: Airscreening one-two times results in a very pure product.

Seed storage 

cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone NI

References

Chayka, K. (n.d.). Verbena hastata (blue vervain). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/blue-vervain 

Hilty, J. (2019). Blue vervain - Verbena hastata. Illinois Wildflowers. https://www.illinoiswildflowers.info/wetland/plants/bl_vervain.htm 

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

Kirk, S. and S.Belt. (2010).  Plant fact sheet for blue vervain (Verbena hastata).  USDA-Natural Resources Conservation Service, Norman A. Berg National Plant Materials Center.  Beltsville, MD 20705.

Moerman, D. (2003). Native American ethnobotany database. BRIT. http://naeb.brit.org/

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 28, 2024).

North Carolina State Extension (n.d.) Verbena hastata. North Carolina Extension Gardener Plant Toolbox. https://plants.ces.ncsu.edu/plants/verbena-hastata/

Society for Ecological Restoration, International Network for Seed Based Restoration and Royal Botanic Gardens Kew. (2023) Seed Information Database (SID). Available from: https://ser-sid.org/ (February 2023)

USDA-NRCS. (2022). Conservation cover native seeding calculator [Excel File]. Retrieved from https://bit.ly/IA_OTH_Conservation_Cover-Native_Seeding_Calculator_2022

USDA NRCS National Plant Data Team. (n.d.). Verbena hastata L. USDA plants database. https://plants.usda.gov/plant-profile/VEHA2 

Species Guide Updated 12/18/2024

Rudbeckia subtomentosa, Pursh 

Alternate Common Names: sweet black-eyed susan, fragrant coneflower

Family: ‌aster and daisy family (Asteraceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial with a fibrous root system, forming clumps of stems from short rhizomes.

Height: 3 - 6 ft  

Leaves and stem

Leaves alternate with short, dense hairs; lower leaves stalked and with 3-5 deep lobes, lobes and petioles decreased to absent from upper leaves; stem is hairy and grooved, branched above.

Flower, fruit and seedhead

Flower: Composite heads 2-3 in across have 10 to 20 widely spreading, yellow rays surrounding a dark brown to black cone of numerous tiny, fertile disk florets. 

Fruit/seedhead: Ray florets drop, leaving a cone of disk florets that ripen to form the “seeds” (achenes).

Pollination: Insects, especially native bees, but also wasps, flower flies, beetles and small to medium-sized butterflies such as skippers.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 43,000 (IA NRCS)

1000 seed weight: 0.94g (Seed Information Database)

Description: “Seed” is a blackish achene, about 3 mm long, wedge-shaped, with no pappus.

Typical seed test 

PLS: 92% (n = 10)

Purity: 95% (n = 9)

Germination: 50% (n = 6)

Dormancy: 36% (n = 7)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Mesic to wet soil; partial to full sun; prairies, woodland openings and edges, savannas, streambanks; Wetland Indicator Status is Facultative Upland (FACU) for the Midwest; mesic loamy soils are recommended for seed production.

Conservation status: Global- G5, secure; Michigan- SX, presumed extirpated; Kentucky, Mississippi, and Texas- S1, critically imperiled; Tennessee- S2, imperiled; Iowa and Kansas- S3, vulnerable; in all other states within its natural range, status is S4 (apparently secure) to S5 (secure) or unranked (NatureServe). 

‌

General Comments

Sweet coneflower (Rudbeckia subtomentosa) is less commonly seen in planted prairies than a related species, blackeyed Susan (R. hirta). Both species have been adopted into the horticultural trade due to their long-lasting and showy flower heads. R. subtomentosa is typically a taller plant, has foliage with lobed leaves and shorter hairs, and is longer-lived than its cousin. The flowers of sweet blackeyed Susan provide pollen and nectar to a wide variety of native bees and other insects, and the seedheads release a sweet smell when crushed. The plants are relatively long-lived in production. They are sensitive to broad-leaf herbicide drift, but how much this affects seed production is unknown.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience with direct seeding this species for seed production.

 

‌‌Greenhouse

Seed pre-treatment: Cold/moist stratification for 30-60 days.

Sowing: Sow in a greenhouse 2-3 months before last frost. Surface sow or very lightly cover the small seeds with a fine seed starting mix.

Transplanting: When seedlings form well-rooted plugs, transplant at 8-12 in spacing in rows prepared with plastic mulch.

‌Appendix A

Stand management

Weeds: Prepare a clean, weed-free bed. Plastic mulch suppresses weeds in the first year or two. Plants are tall, and once well-established, compete effectively with smaller annual weeds and cool-season grasses. Hand weed or rogue out weeds that could contaminate the seed lot.

Pests: No serious issues noted. Caterpillars of the gorgone checkerspot butterfly form gregarious feeding clusters and strip a few leaves, but this is more of a curiosity than a problem.

Diseases: None noted.

Herbicide susceptibility: Leaves show signs of herbicide injury (cupping and twisting) from exposure to drift from synthetic auxin herbicides.

Seed production

First harvest: A small harvest may be expected in the establishment year (from transplants).

Yield/acre: 40-225 pounds per acre (per acre yields extrapolated from harvest records of 4 plots)

Stand life: Plants persist for ten years or longer, although seed production declines after reaching a peak in the third year after transplanting.

Flowering date: early July through early September in northeast Iowa

Seed maturity/Harvest date: late September through mid October

Seed retention: Low risk of shattering; shattering begins in mid October.

Harvest date range at TPC (2004-2020): September 22 - November 3

Recommended harvest method: Combine 

Appendix B

Seed cleaning and storage

Cleaning process: Pass combined material through 1/2 in and 1/4 in mesh to remove larger particles, then airscreen. Several passes may be needed to separate the achenes from chaffy bracts of a similar size and weight. If harvested material contains unbroken heads (“cones”), brush with medium bristles to thresh achenes from heads.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone EA (eastern Iowa)

Cultivated varieties: Selections have been made for the horticultural trade.

References

Chayka, K. (n.d.). Rudbeckia subtomentosa (Sweet Coneflower). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/sweet-coneflower 

Christiansen, P., & Muller, M. (1999). Asteraceae. An Illustrated Guide to Iowa Prairie Plants. (p. 66). University of Iowa Press.

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Sweet coneflower. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 107). University of Wisconsin-Madison Arboretum.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

USDA NRCS National Plant Data Team. (n.d.). Rudbeckia subtomentosa Pursh. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=RUSU

Species Guide Updated 12/29/2025

Liatris aspera Michx.

Alternate Common Names: rough blazing star, rough blazingstar, rough blazing-star, tall gay-feather, gayfeather, button snakeroot, rough gayfeather

Scientific Synonyms: Lacinaria scariosa var. intermedia Lunell, Liatris aspera var. intermedia (Lunell) Gaiser, Liatris aspera var. salutans (Lunell) Shinners, Liatris spheroidea var. salutans (Lunell) Shinners

Family: ‌aster family (Asteraceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial with a woody corm that can be divided.

Height: 1-4 ft  

‌

Leaves and stem

Leaves narrowly lanceolate, alternate, with a prominent central vein and short stiff hairs; stem is rigid and rough with short hairs, green or purple in color, usually unbranched.

Flower, fruit and seedhead

Flower: Pinkish purple heads, 1 in across, are spaced along the stalk, button-like, in a 6-18 in long spike; plants in production plots may be taller and produce robust, branched inflorescences. Heads of Liatris aspera are usually sessile or very short-stalked, compared with the stalked (pedunculate) heads of Liatris ligulistylis, Rocky Mountain blazing star, which is otherwise quite similar. Bracts on the underside of L. aspera heads are strongly cupped, while L. ligulistylis bracts tend to be flattened toward the top.

Fruit/seedhead: Dark brown seeds are 1/4 in long, ribbed, with a light brown pappus (fluff) that is finely barbed but not feathery; wind dispersed.

Pollination: Insects such as bees, butterflies, moths, and flies

Seed

Appendix D

‌Seed characteristics 

Seeds per ounce: 16,000 (IA NRCS)

1000 seed weight: 2.11 g (Seed Information Database)

Description: “Seeds” are achenes, nearly black, about 1/8 in to nearly 1/4 in long, with tufts of light brown hairs (pappus).

Typical seed test 

PLS: 93% (n = 10)

Purity: 96% (n = 10)

Germination: 27% (n = 8)

Dormancy: 66% (n = 10)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Dry to dry-mesic, even sandy or rocky soil; full sun; prairies, savannas, prairie remnants along railroads, upland forests, limestone glades. Upland, very well-drained, loamy soils are preferred for seed production. If soils are too dry or poor, seed production will be curtailed.

Conservation status: Global- G4, apparently secure; North Carolina- S1, critically imperiled; South Carolina- S2, imperiled; Georgia and Virginia- S3, vulnerable (NatureServe) 

General Comments

This species is best propagated in the greenhouse, and transplanted in spring into a weed-free planting bed or weed barrier. Seedlings develop pea-size corms after two months in the greenhouse. Sometimes first year corms are exposed by frost-heaving over the winter, and may be eaten by voles. Species in the genus Liatris are known to hybridize, therefore proper isolation should be maintained between related species to avoid hybrid seed production (Levin 1968, Menhusen 1972). Liatris species are also produced commercially for the cut-flower industry and some species and cultivars have become popular in gardening and landscaping.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Not recommended for this species

 

‌‌Greenhouse

Seed pre-treatment: Wet stratify 8-12 weeks at 40˚ F. Seed sometimes becomes moldy in stratification, and some growers add fungicide to the stratification media.

Sowing: Sow seed 1/4 in deep in the greenhouse two months before the last frost free date.

Transplanting: Harden off, transplant into bare soil in rows and mulch or transplant into a weed barrier at 8 in intervals after all danger of frost is past.

‌Appendix A

Stand management

Weeds: Mow/cultivate between rows, mulch within rows. Post emergence grass herbicide, tillage, hoeing, hand roguing. Very sensitive to soil disturbance during bolting/flowering, so clip weeds rather than pulling or hoeing once flower stalks are apparent.

Pests: Voles will eat and/or cache corms, rabbits and deer eat young shoots, goldfinches consume seed as it ripens.

Diseases: Powdery mildew, root-knot nematodes, stem rot, verticillium wilt.

Hybridization risk: This species has been known to hybridize with related species Liatris acidota, L. ligulistylis, L. punctata, L. pycnostachya, and L. squarrosa.

Seed production

First harvest: Remains vegetative first year (seedlings), abundant flowering/seed production occurs second year. Fall corm division/transplanting results in abundant flowering the following growing season.

Yield: 8-130 bulk pounds/acre (extrapolated from harvests of 5 plots)

Stand life: Peak harvests second year. Good harvest third year if proper soils. Stand declines significantly fourth year and after. Plants tend to lodge second year when flowering.

Flowering date: early August - early September in northern Iowa

Seed maturity/Harvest date: late September - mid-October in northern Iowa

Seed retention: wind dispersed soon after maturity

Harvest date range at TPC (2003-2023): Sept 29 - Nov 6

Recommended harvest method: Combine at maturity, but before pappus is dry and fluffy. Seedheads mature from the top down along a stalk. When the topmost heads are fluffy, break open a few of the lower heads and observe for signs of maturity: dark-colored seeds that separate easily from the base of the head. Small plots may be hand harvested by clipping stalks as the seed matures, then drying the cut material in a building. Dry seed threshes easily from stalks.

Appendix B

Seed cleaning and storage

Cleaning process: Pre-clean by scalping thru 1/2 in mesh to remove large particles and make the material flowable, brush gently with soft-bristles to remove ‘plumes’ (pappus), using care not to damage seed coat, then air screen.

Seed storage: cool/dry (33-50° F, 30-50% RH); stores well for a few years if seed is not damaged during cleaning.

Appendix C

Released Germplasm 

Source Identified material: Northern Iowa Germplasm (IA Zone 1), Central Iowa Germplasm (IA Zone 2), Southern Iowa Germplasm (IA Zone 3)

References

Chayka, K. (n.d.). Liatris aspera (rough blazing star). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/rough-blazing-star

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Rough blazing-star. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 95). University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). Rough blazingstar - Liatris aspera. Illinois Wildflowers. https://www.illinoiswildflowers.info/prairie/plantx/rgh_blazingstarx.htm 

Houseal, G. A. (2007). Forbs wildflowers. In G. A. Houseal (Eds.), Tallgrass Prairie Center’s native seed production manual (pp. 38–39). Tallgrass Prairie Center - University of Northern Iowa.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

Levin, D.A. (1968). The Structure of a Polyspecies Hybrid Swarm in Liatris. Evolution, 22(2), 352-372. https://doi.org/10.1111/j.1558-5646.1968.tb05903.x 

Menhusen, B.R. (1972). Ecology of the Prairie Species of the Genus Liatris. Third Midwest Prairie Conference Proceedings. Manhattan, Kan.: Division of Biology, Kansas State University. https://search.library.wisc.edu/digital/AL7JMUVRYYXDZO8S/pages/A56MVY3FXXELEL8L

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 29, 2024).

Nesom, G. L. (2020, November 5). Liatris aspera Michaux. Flora of North America. http://floranorthamerica.org/Liatris_aspera 

Runkel, S. T., & Roosa, D. M. (2009). Rough blazing star. In Wildflowers of the tallgrass prairie: The upper Midwest (2nd ed., pp. 220–221). University of Iowa Press.

USDA NRCS National Plant Data Team. (n.d.). Liatris aspera Michx. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=LIAS

Species Guide Updated 2/14/2024

Artemisia ludoviciana Nutt.

Alternate Common Names: white sage, prairie sage, western mugwort, Louisiana sage, prairie wormwood, cudweed, mugwort, dark-leaved mugwort, sagewort, western sage, sailor’s tobacco, sagebrush

Scientific Synonym: Artemisia vulgaris var. ludoviciana (Nuttall) Kuntze 

Functional Group: forbs (wildflowers)

Family: ‌aster or sunflower family (Asteraceae)

Description 

Life cycle and growth form

Perennial, spreading by rhizomes to form large colonies that exclude some other plants.

Height: 1-3 ft

‌

Leaves and stem

‌

Alternate leaves, aromatic when crushed, of variable shape but mostly narrow, elongated ellipses up to 1 in wide and 3.5 (occasionally up to 5) in long, short-stalked or sessile, with silvery-white hairs on leaves and stems giving them a felt-like texture; stems may be branched or unbranched.

Flower, fruit and seedhead

‌Flower: Individual florets are inconspicuous within silvery, barrel-shaped, 1/8 in heads arranged in clusters in upper leaf axils or in spike-like to open, branched arrays up to 17 in in length; at full flowering, yellow stamens and minute, yellow to reddish corollas may be visible; wind-pollinated.

Fruit/seedhead: Roughly cylindrical in shape, approximately 1/8 in long, pappus is absent, heads open to release seed (achenes) when mature.

‌

Seed

Appendix D

‌Seed characteristics 

Seeds per ounce: 250,000 (IA NRCS)

1000 seed weight: 0.11 g (Seed Information Database)

Description: Cypsela (achene), elliptical in outline, about 0.5 mm long, light grayish-brown, without hairs or attached fluff (pappus).

Typical seed test 

PLS: 84% (n = 11)

Purity: 92% (n = 11)

Germination: 30% (n = 10)

Dormant: 57% (n = 11)

(averages obtained from n tests of purchased seed lots)

Habitat and range

Habitat: Dry to mesic soil; full sun; sandy or rocky prairies, roadsides. Wetland Indicator Status is Obligate Upland (UPL) for the Midwest.

Conservation status: Global- G5, secure; Michigan- S1, critically imperiled (NatureServe)

‌

General Comments

All above ground parts of the plant have a distinctive sage-like fragrance when rubbed or crushed. This species has traditional medicinal and ceremonial uses among numerous Native American tribes. Because it is wind-pollinated, white sagebrush is not considered a resource for pollinators, though it is a larval host for at least one species of moth caterpillar, Phaneta argenticostana. Its mode of vegetative spread produces a dense network of rhizomes and roots that function in erosion control.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience direct-seeding this species for seed production.

‌‌Greenhouse

Seed pre-treatment: 60 days cold-moist stratification (fine silica sand)

Sowing: Surface (seed is small and must not be buried too deeply); seed directly onto plug flats or start seedlings in germination trays and dibble into plugs when seedlings have first true leaves; start in greenhouse about 8-10 weeks prior to transplanting.

Transplanting: Harden off seedlings 1-2 weeks prior to transplanting; transplant with 12 in plant spacing in plasticulture plots or into bare soil in 36 in rows, after danger of frost; cut or remove plastic after the first full growing season to allow plants to spread by rhizomes.

Note: Also readily propagated through division or rhizome cuttings (see NRCS Plant Guide referenced below).

‌Appendix A

Stand management

Weeds: Few issues as dense, young colonies tend to exclude weeds; other small-seeded members of the aster family (e.g., frost aster, Symphyotrichum pilosum, and marestail, Erigeron canadensis) could contaminate seed and should be rogued out before harvest.

Pests: None noted.

Diseases: None noted.

Seed production

First harvest: In fall of first year when started from greenhouse transplants.

Yield: 15-60 pounds/acre (based on 5 plots)

Stand life: Peak seed production in the first two years, then declining.

Flowering date: late August - September

Seed maturity/Harvest date: Mid-October in northeast Iowa; gauge maturity by sampling heads from several plants and crushing to reveal developing seeds (a hand lens is helpful); mature seed will have a grayish-brown color and separate easily from the receptacle; watch for heads to open and release seed when mature; seed shatters easily and will be lost if harvest delayed.

Seed retention: Shattering begins once seedheads open in mid to late October.

Harvest date range at TPC (2003-2023): July 17 - Oct 28

Recommended harvest method: Combine at maturity or cut/swath stems when about 10% of plants in the plot have open seed heads and lay to dry in shed, then run through stationary combine.

Appendix B

Seed cleaning and storage

Cleaning process: Brush (Westrup LA-H) with stiff bristles and #14 screen mantle to release seed from heads, use minimal vacuum; airscreen several times.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source identified material: Natural Selections/Iowa Ecotype Project Zones 1, 2, and 3

Cultivated variety (cultivar): Summit (LA); horticultural varieties may also exist.

References 

Chayka, K. (n.d.). Artemisia ludoviciana (white sage). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/white-sage

Christiansen, P., & Muller, M. (1999). White sage - Artemisia ludoviciana Nutt. Prairie plants of Iowa - Artemisia ludoviciana Nutt. https://uipress.lib.uiowa.edu/ppi/display.php?record=Artemisia_ludoviciana

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). White sage. In Prairie plants of the University of Wisconsin, Madison Arboretum (3rd ed., p. 68). University of Wisconsin-Madison Arboretum. 

Flora of North America Editorial Committee. 2006a. Flora of North America North of Mexico. Vol. 19. Magnoliophyta: Asteridae, part 6: Asteraceae, part 1. Oxford University Press, New York. xxiv + 579 pp.

Hilty, J. (2020). White sage - Artemisia ludoviciana. Illinois Wildflowers.   https://www.illinoiswildflowers.info/prairie/plantx/white_sagex.htm

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 16, 2024).

Runkel, S. T., & Roosa, D. M. (2009). Prairie sage. In Wildflowers of the tallgrass prairie: The upper Midwest (Second, p. 237). University of Iowa Press. 

Shultz, Leila M. (2020, November 6). Artemisia ludoviciana Nuttall. Flora of North America. http://floranorthamerica.org/Artemisia_ludoviciana  

Society for Ecological Restoration, International Network for Seed Based Restoration and Royal Botanic Gardens Kew. (2023) Seed Information Database (SID). Available from: https://ser-sid.org/ (February 2023)

Stevens, M., & Roberts, W. (2000). Plant guide - USDA Plants Database - White sage, Artemisia ludoviciana Nutt. https://plants.usda.gov/DocumentLibrary/plantguide/pdf/cs_arlu.pdf 

Species Guide Updated 12/19/2024

Asclepias verticillata, L. 

Alternate Common Name: eastern whorled milkweed

Family: ‌dogbane family (Apocynaceae), formerly milkweed family (Asclepiadaceae)

Functional Group: forbs (wildflowers)

Description 

Life cycle and growth form

Perennial that forms extensive clonal patches from deep, spreading rhizomes.

Height: 1 - 2 ft  

Leaves and stem

Bright green needle-like leaves, up to 2-3 in long, with margins that are rolled to the underside, in whorls of 4-6 at nodes; slender stem, usually unbranched, with short hairs in vertical lines.

Flower, fruit and seedhead

Flower: Typical milkweed flower, slightly greenish white, with a central reproductive column surrounded by a 5-part corona of nectar-filled hoods, 5 downcurved petals, and 5 sepals (hidden by the petals when in bloom); multiple 1-3 in rounded clusters of flowers (umbels) in upper leaf axils.

Fruit/seed head: Fruit is a slender, hairless, elongated follicle (commonly called a “pod”) up to 3-4 in long, releasing plumed oval brown seeds at maturity; seed is wind-dispersed.

Pollination: Insects, especially bees and wasps, as well as flies, butterflies, and moths. We have observed the endangered rusty patched bumble bee using these flowers.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 11,000 (IA NRCS)

1000 seed weight: 2.20g (Seed Information Database)

Description: Seeds are dark brown, teardrop-shaped with a flattened wing, about 5 mm long, with a tuft of silky fluff (coma or floss) prior to cleaning.

Typical seed test 

PLS: 92% (n = 11)

Purity: 97% (n = 10)

Germination: 19% (n = 5)

Dormancy: 36% (n = 5)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Dry to mesic soil; partial to full sun; dry to dry-mesic prairies, woodlands openings, sandy savannas, limestone glades, rocky bluffs, fields, roadsides; Wetland Indicator Status is Facultative Upland (FACU) for the Midwest; moist to dry loamy to sandy soils are recommended for seed production.

Conservation status: Global- G5, secure; Delaware- SH, possibly extirpated; Rhode Island and Vermont- S1, critically imperiled; Massachusetts, New Jersey, New York, and Pennsylvania- S2, imperiled; Maryland and West Virginia- S3, vulnerable; in all other states within its natural range, status is S4 (apparently secure) to S5 (secure) or unranked (NatureServe).

General Comments

In the late summer to early fall in the Tallgrass Prairie Center seed production fields, one of the best places to look for monarch butterfly caterpillars is on whorled milkweed plants. It may seem surprising to find large, late-instar caterpillars on these slender plants with their needle-like leaves, so unlike their robust cousin common milkweed.  Each whorled milkweed stem is small, but the plant’s clonal nature means that an individual plant can have many stems, and a large caterpillar can simply mow down one after another. We often see clones of whorled milkweed on roadsides and highway medians that are mowed in spring, as well as in parts of native prairies where the vegetation is a bit sparse. In single-species, densely planted production plots, this species is productive for a year or two, then declines rapidly. We plan to investigate other methods, such as planting at low density within a grassy matrix, to see if the plants will remain productive for a longer period of time.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not have experience with direct seeding this species for seed production.

 

‌‌Greenhouse

Seed pre-treatment: 60 days cold/moist stratification or 24-hour treatment with 250 ppm GA-3 just prior to sowing.

Sowing: Sow seed, lightly covered, in the greenhouse about 2 months before the typical frost free date.

Transplanting: When plugs are well-rooted, move them outside to harden off, then transplant into prepared rows. We have planted them at 12 in spacing in plasticulture rows in the past, but the plants decline in year 2 and 3. We are planning to replant at a 3-4 ft spacing in an open, grassy matrix to allow vegetative spread.

‌Appendix A

Stand management

Weeds: Prepare a clean, weed-free bed. Plastic mulch suppresses weeds in the first growing season but must be removed at the end of the year to allow new growth and vegetative spread. We will be attempting a new planting in an existing grassy area where the perennial grasses may help to suppress weeds. Since we hand collect the fruits as they ripen, weeds are of little concern for seed purity.

Pests: Invasive oleander aphids (bright yellow-orange) can form dense infestations on stems and flower heads. Native milkweed bug adults and their gregarious nymphs (young) pierce developing seed pods and damage the seeds. Monarch caterpillars and milkweed beetles feed on the foliage, but their density is rarely high enough to cause measurable damage.

Diseases: Plants in dense plantings appear unhealthy and stressed after the second year. We have not identified any particular diseases in these plots, but milkweeds are known to be susceptible to a variety of plant diseases.

Hybridization risk: This species may hybridize with other members of the milkweed genus, Asclepias. Maintain separation distances between plots of these species.

Seed production

First harvest: Expect abundant flowering and seed set in the establishment year.

Yield/acre: 30-40 pounds per acre during peak yield (extrapolated from harvests of four plots at TPC)

Stand life: Plants are most productive in the establishment year and their second year but decline rapidly thereafter.

Flowering date: late June through early September in northeast Iowa

Seed maturity/harvest date: Late August through early October in northeast Iowa; however, seed maturity may be delayed in the planting year or if plants are mowed in early summer.

Seed retention: High risk of shattering. Fluffy seed disperses from pods as they split open at maturity. 

Harvest date range at TPC (2015-2023): August 29 - November 20, though usually completed by early October.

Recommended harvest method: Check fields several times per week during the harvest window and hand pick fruits when nearly mature but not yet open. The pods become lighter and yellower in color and soften as they ripen and pop easily when gently squeezed. Combining should be successful when about 10-20% of the pods in a plot have opened, though we have not attempted this. 

Appendix B

Seed cleaning and storage

Cleaning process: Protect eyes and airways from the abundant fluff that is released during the cleaning process. Large amounts of hand collected pods can be run through a debearder to break up the pods and remove the fluff from the seeds. Pass the material through 1/2 in and 1/4 in mesh to remove larger particles. If possible, do this step outside on a day with a light, steady wind. Finish by airscreening.

Seed storage: cool/dry (33-50° F, 30-50% RH)

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone 1 (northern Iowa), Zone 2 (central Iowa)

References

Borders, B. & Lee-Mäder, E. (2014). Milkweeds, A Conservation Practitioners Guide. Xerces Society for Invertebrate Conservation. https://www.xerces.org/publications/guidelines/milkweeds-conservation-practitioners-guide 

Chayka, K. (n.d.). Asclepias verticillata (whorled milkweed). Minnesota Wildflowers. https://www.minnesotawildflowers.info/flower/whorled-milkweed 

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Whorled milkweed. In Prairie plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 59). University of Wisconsin-Madison Arboretum.

Kartesz, J.T., The Biota of North America Program (BONAP). 2023. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2023. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)]

Lady Bird Johnson Wildflower Center - The University of Texas at Austin. (2022). Asclepias verticillata. Plant Database. https://www.wildflower.org/plants/result.php?id_plant=asve 

NatureServe. 2024. NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer [web application]. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org/. (Accessed: February 28, 2024).

USDA NRCS National Plant Data Team. (n.d.). Asclepias verticillata L. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=ASVE

Species Guide Updated 12/23/2025