Carex bicknellii Britton 

Alternate Common Names: Bicknell’s oval sedge, copper-shouldered oval sedge

Scientific Synonyms: Carex bicknellii Britton var. bicknellii, Carex brevior. (Dewey) Mack var. crawei (W. Boott) B. Boivin, Carex straminea var. crawei Boott, Carex straminea Willd. var. meadii Boott

Family: ‌sedge family (Cyperaceae)

Functional Group: sedges and rushes

Description 

Life cycle and growth form

perennial, short black rhizomes, forms bunches

Height: 1-4 ft  

Leaves and stem

3-4 leaves per stem, alternate, three-ranked, rough margins, pale green, flat and thin

Flower, fruit and seedhead

Flower/fruit/seedhead: Erect to arching seed heads 2-6 cm long; 3-6 oval spikes with cone-shaped bases, each 10-18 mm long, per stem.

Pollination: wind

Seed

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 17,000 seeds/oz (IA NRCS)

1000 seed weight: 1.31g (Seed Information Database)

Description: Achene broadly elliptical, brown; mature perigynium (sac-like structure around the achene) flattened, with a translucent and membranous wing, distinct, parallel veins, and coppery-brown “shoulders,” the source of one alternate common name, “copper-shouldered oval sedge.”

Typical seed test 

PLS: 84% (n = 11)

Purity: 98% (n = 10)

Germination: 30% (n = 7)

Dormancy: 61% (n = 7)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Dry to moist soil; full sun; prairies, rock outcrops, savannas, along railroads; Wetland Indicator Status is Facultative Upland (FACU) for the Midwest.

Conservation status: Global- G5, secure; Delaware- SX, presumed extirpated; Vermont- SH, possibly extirpated; Arkansas, Maine, New Hampshire, Pennsylvania, and South Carolina- S1, critically imperiled; Massachusetts- S1/S2, critically imperiled to imperiled; New Jersey and Ohio- S2, imperiled (NatureServe)

‌

General Comments

Sedges are a large, diverse group of grass-like plants that are important components of prairies, wetlands, and woodlands across our region. In Iowa alone, there are about 120 species of sedges. Grasshoppers and the larvae of skipper butterflies, among other insects, feed on sedge foliage, and their seeds are eaten by grassland birds.  They are notoriously difficult to identify to species, especially the oval sedges to which Bicknell’s sedge belongs. The development of stock seed by the Tallgrass Prairie Center in the early 2000s enabled broader access to reliably identified sedge species by native seed growers. The large, winged perigynia of Carex bicknellii, with their pearly color and translucence, make this species somewhat easier to identify than other oval sedges. This species is also one of a few oval sedges that are commonly found in upland prairie habitats. Seed production plots of Carex bicknellii in mesic to dry mesic soils do not require irrigation.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Not recommended for this species.

 

‌‌Greenhouse

Seed pre-treatment: 30 days cold-moist stratification; removal of perigynia produces a similar effect as stratification on germination in this species.

Sowing: Sow in germination flats or directly into plugs (2-3 seeds per cell), covering seed lightly (light improves germination of many sedge species); maintain even moisture until germination. Daytime temperatures should be around 70-80°F (22-27°C) and allowed to drop at night to 50-60°F (10-15°C). We have had good success planting into 2.5 in deep, 73-cell plug flats that are ridged to direct root development downward and have 3/4 in bottom openings to encourage root pruning and the formation of firmly rooted plugs for transplanting.

Transplanting: Seedlings are ready to transplant to the field about 10 weeks after sowing. 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.’

‌Appendix A

Stand management

Weeds: Plastic mulch reduces weed pressure in the first year or more. Holes in the plastic should be widened somewhat in subsequent years to allow the bunches to expand. The most significant weed issue can be the presence of other oval sedges such as Carex brevior and Carex molesta, since they are competitive and their seed is difficult to distinguish from Carex bicknellii in the field and practically impossible to clean out of harvested seed. Obtaining clean, reliably identified, certified stock seed helps to prevent this issue.

Pests: None noted.

Diseases: None noted.

Seed production

First harvest: There may be a small amount of seed in the first season, but most plants begin flowering and producing seed in their second growing season after transplanting.

Yield: Peak harvests are in the second through fourth years after transplanting, with yields from 40-112 pounds per acre, extrapolated from harvests of four plots grown at the Tallgrass Prairie Center.

 

 

Stand life: Plants may persist for up to ten years or more, but productive stand life is about five years, after which our yields have declined.

Flowering date: June in northeast Iowa

Seed maturity: Mid-late June to early July

Seed retention: Significant shattering occurs in high winds when perigynia are mature; lodging can also occur due to heavy rains/storms, complicating combine harvest.

Harvest date range at TPC (2007-2023): June 14 - July 31

Recommended harvest method: Combine when mature; a good rule of thumb is to wait until about 10% of seed heads have begun shattering.

Appendix B

Seed cleaning and storage

Cleaning process: Air-dry seed for two weeks or more after harvest. Pass material through a coarse screen (1/2 in hardware cloth) to remove larger stemmy material, if needed, then air screen. If perigynia removal is desired, pass material through a brush machine with medium bristles before air screening. (Note: perigynia removal destroys several characteristics used in identification.)

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

Appendix C

Released Germplasm 

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

References

Boeck Crew, C.M., Myers, M.C., Sherrard, M.E., Elgersma, K.J., Houseal, G.A., & Smith D.D. (2020). Stratification and perigynia removal improve total germination and germination speed in 3 upland prairie sedge species. Native Plants Journal, 21(2), 120-131. https://doi.org/10.3368/npj.21.2.120 

Chayka, Katy. (n.d.). Carex bicknellii (Bicknell’s sedge). Minnesota Wildflowers. https://www.minnesotawildflowers.info/grass-sedge-rush/bicknells-sedge

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Bicknell’s Sedge. In Prairie Plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 160). University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). Bicknell’s sedge - Carex bicknellii. Illinois Wildflowers. https://www.illinoiswildflowers.info/grasses/plants/bicknell_sedge.htm

Houseal, G. (2010). Plasticulture for seed production of wetland (Carex) species. Native Plants Journal, 11(1), 58-64. https://doi.org/10.2979/NPJ.2010.11.1.58   

Mastrogiuseppe, J., Rothrock, P. E., Dibble, A. C., & Reznicek, A. A. (2020, November 5). Carex bicknellii Britton. Flora of North America. http://floranorthamerica.org/Carex_bicknellii  

Mohlenbrock, R. H. (1999). Carex bicknellii. In Illustrated Flora of Illinois - Sedges: Carex (p. 139). Southern Illinois University Press.

Murphy, M. & Spyreas, G. & Marcum, P. (2025) Carex of Illinois & Surrounding States: The Oval Sedges. University of Illinois 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).

Schütz, W. & Rave, G. (1999). The effect of cold stratification and light on the seed germination of temperate sedges (Carex) from various habitats and implications for regenerative strategies. Plant Ecology 144, 215–230. https://doi.org/10.1023/A:1009892004730 

USDA NRCS National Plant Data Team. (n.d.). Carex bicknellii Britton. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=CABI3 

Species Guide Updated 2/5/2025

Carex buxbaumii, Wahlenb. 

Alternate Common Name: brown bog sedge

Scientific Synonym(s): Carex buxbaumii var. anticostensis Raymond, Carex holmiana, Carex polygama Mackenzie

Family: ‌sedge family (Cyperaceae)

Functional Group: sedges and rushes

Description 

Life cycle and growth form

Perennial, long-rhizomatous, forming large stands with a distinctive bluish-green color compared with the yellow-green of most sedges.

Height: 1-2.5 ft  

Leaves and stem

Leaves flat, hairless, and rough on the edges; lower sheaths are rusty brown and ladder fibrillose (made of evenly spaced, linked fibers) near their tops, flowering stems are stiff and 3-sided, smooth.

Flower, fruit and seedhead

Fruit/seedhead: 1-4 spikes per plant; pistillate spikes bear up to 40 perigynia per spike, distinctive scales are red-purple to dark brown with a green midvein, perigynia (papery coverings around each “seed”) are hairless and gray-green, can be beakless or have a tiny beak, “seeds” (achenes) are 3-sided.

Pollination: wind

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 14,500 (IA NRCS)

1000 seed weight: 1.66 g (Seed Information Database)

Description: Seed unit is an achene (2 mm long) with surrounding perigynium (1.5 x 3 mm); perigynia are gray-green with lighter veins and a very short beak; achene is three-sided and brown.

Typical seed test 

unknown at this time.

Habitat and range

‌Habitat: Mesic to wet soil; partial to full sun; prairie swales, meadows, fens, marshes, ditches; Wetland Indicator Status is Obligate Wetland (OBL) for the Midwest; irrigation is recommended for seed production.

Conservation status: Global- G5, secure; District of Columbia and Georgia- SH, possibly extirpated; Arkansas, Connecticut, Delaware, Kansas, Kentucky, New Hampshire, South Carolina, South Dakota, Tennessee, and Vermont- S1, critically imperiled; Maryland, Missouri, Nebraska, Nevada, Massachusetts, New York, North Carolina, North Dakota, Virginia, and West Virginia- S2, imperiled; California, Idaho, New Jersey, Pennsylvania, Washington, Wyoming, and Illinois- S3, vulnerable (NatureServe) 

General Comments

Sedges are a large, diverse group of grass-like plants that are important components of prairies, wetlands, and woodlands across our region. In Iowa alone, there are about 120 species of sedges. Grasshoppers and the larvae of skippers and other butterflies and moths feed on wetland sedge foliage, and their seeds are eaten by waterfowl and other birds. Sedges are notoriously difficult to identify to species. Buxbaum’s sedge is distinguishable by, among other characteristics, its rhizomatous habit, bluish green foliage, and dark purplish-brown scales in the seedheads (spikelets). The development of stock seed by the Tallgrass Prairie Center in the early 2000s enabled broader access to reliably identified sedge species by native seed growers. As an obligate wetland species, Buxbaum’s sedge benefits from irrigation in production settings.

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: Benefits from cold-moist stratification for at least 60 days.

Sowing: Sow in germination flats, covering seed lightly (light improves germination of many sedge species); germination may be slow and sporadic. Daytime temperatures should be around 70-80°F (22-27°C) and allowed to drop at night to 50-60°F (10-15°C). We have had good success dibbling seedlings into 2.5 in deep, 73-cell plug flats that are ridged to direct root development downward and have 3/4 in bottom openings to encourage root pruning and the formation of firmly rooted plugs for transplanting.

Transplanting: Seedlings are ready to transplant to the field about 14-16 weeks after sowing. 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.’

‌Appendix A

Stand management

Weeds: Plastic mulch reduces weed pressure in the first year or more. Plastic must eventually be removed to allow the plants to spread by rhizomes. A well-established stand outcompetes many weeds. In large-scale production systems or those where the use of weed barriers and/or hand weeding is not practical, broad-leaf herbicides and/or pre-emergent herbicides may be useful to prevent weeds from competing with the sedge plants and/or complicating the seed cleaning process. Significant weed problems may be caused by winter annuals (e.g., members of the mustard family), other small-seeded broad-leaf annuals, and annual grasses (e.g., downy brome). Herbicide applications should be timed to most effectively control specific weeds and minimize damage to the sedge plants. Care must be taken to read affected “weed” lists, as sedges are considered weeds in crop systems. Always read and follow label instructions.

Pests: None noted.

Diseases: None noted.

Seed production

First harvest: Small amounts may be produced in the first and second years after transplanting.

Yield/acre: 24-340 lbs per acre

Stand life: Appears to take 3 years to reach peak production; plants are likely long-lived, but uncertain whether yields will be sustained or sporadic; mowing in fall or winter may improve yields in subsequent seasons.

Flowering date: May in northern Iowa

Seed maturity/harvest date: Mid to late June in NE Iowa.

Seed retention: Moderate shattering observed.

Harvest date range at TPC (2010-2011, 2025): June 16 - 27

Recommended harvest method: Combine at maturity; seed threshes cleanly. 

Appendix B

Seed cleaning and storage

Cleaning process: Air-dry combined material for two weeks or more after harvest. Pass material through a coarse screen (1/2 in hardware cloth) to remove larger stemmy material, if needed, then air screen.

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

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone Iowa

References

Carex buxbaumii (Buxbaum’s Sedge). Minnesota Wildflowers. (n.d.). https://www.minnesotawildflowers.info/grass-sedge-rush/buxbaums-sedge

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Buxbaum’s Sedge. In Prairie Plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 161). essay, 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)]

Murray, D. F. (2020, November 5). Carex buxbaumii Wahlenberg. Flora of North America. http://floranorthamerica.org/Carex_buxbaumii 

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.). Carex buxbaumii Wahlenb.. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=CABU6 

Species Guide Updated 12/2/2024

Juncus dudleyi, Wiegand

Scientific Synonyms: Juncus tenuis Willd. var. dudleyi (Wiegand) F.J. Herm., Juncus tenuis Willd. var. uniflorus auct. non Farw. p.p.

Family: ‌rush family (Juncaceae)

Functional Group: sedges and rushes

Description 

Life cycle and growth form

Perennial, bunch forming rush with fine fibrous roots and short rhizomes.

Height: 1-2 ft  

Leaves and stem

Leaf blades flat, dark green, up to 1 mm wide and 12 in long, 2-3 leaves per flowering stem; flowering stems longer than the blades, round in cross-section; small appendages where the leaf blade meets the sheath (auricles) are thickened, rounded, often yellowish, helping to distinguish Dudley’s rush from similar species that have auricles that are elongated and membranous (J. tenuis) or rounded and papery (J. interior).

Flower, fruit and seedhead

Fruit/seed head: Inflorescence is a dense to loose cluster of up to 80 small green, 6-parted flowers that mature into oval brown capsules surrounded by 6 persistent, sharply pointed tepals; usually at least one slender, thread-like bract from the base of the inflorescence extends beyond the flowers; capsules open at maturity to release numerous, very tiny seeds.

Pollination: wind

Seed

Seed image includes a ruler with millimeter markings.

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 3,200,000 (IA NRCS)

1000 seed weight: 0.01 g (Seed Information Database)

Description: Seeds are a slightly curved oval or crescent shape, translucent red-gold in color with a whitish bump on one end (but not a long “tail”). 

Typical seed test 

PLS: 84% (n=5)

Purity: 99.8% (n=5)

Germination: 1.2% (n=5)

Dormancy: 77.4% (n=5)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Moist soils, full sun; wet prairies, fens, marshes, seeps, wet ditches, shores; Wetland Status is FACW (usually occurring in wetlands) for the Midwest; irrigation is recommended for seed production.

Conservation status: Global- G5, secure; Illinois, New Jersey- S3, vulnerable; Alabama, North Carolina, Nevada- S1, critically imperiled; remaining states either S5, secure, S4, apparently secure, or unranked (NatureServe). 

‌

General Comments

Rushes are cool season, somewhat grass-like plants that are usually found in habitats with wet soils. When making collections in remnant habitats for development of Iowa Source Identified seed of Dudley’s rush, we found the plants in both disturbed and high quality prairies, fens, marshes, and ditches. The tiny seeds are sticky when wet and may be dispersed by sticking to the feet of waterfowl and mammals. In our region, there are three species that are very similar, and Dudley’s rush is distinguished primarily by its auricles - little flaps of tissue where the leaf sheath meets the blade - which are thickened and often yellowish in Dudley’s rush in comparison with path rush (J. tenuis) and inland rush (J. interior).

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

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

 

‌‌Greenhouse

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

Sowing: Surface sow in greenhouse about 2-3 months before last frost. Seed is exceptionally tiny, so take care in watering (mist gently) to avoid dislodging. Germination is greatly improved by keeping flats saturated. Seedlings are tiny and threadlike but grow vigorously.

Transplanting: When plugs are well-rooted, move them outside to harden off, then transplant at 8-12 in intervals in plastic mulch with irrigation tape.

‌Appendix A

Stand management

Weeds: Prepare a clean, weed-free bed. Plastic mulch suppresses weeds in the first year or two. Mow or cultivate between rows. Hand-hoe and rogue within rows. Contamination of seed by weedy species is unlikely due to the extremely small size of Dudley’s rush seed enabling removal of weeds in seed cleaning.

Pests: None noted.

Diseases: None noted.

Seed production

First Harvest: Some flowering and seed set may be expected at the end of the first season from transplants.

Yield/Acre: 20-200 pounds per acre (*extrapolated from harvests of one plot)

Stand Life: Unknown at this time but likely 3-5 years. Plants are relatively small, and invasion of plots by larger, competitive weeds is likely to cause loss of yield over time.

Flowering Date: late May to early June in northeast Iowa

Seed Maturity/Harvest Date: early to mid July in northeast Iowa

Seed retention: Moderate risk of shattering; some seed is lost as soon as capsules open, but some is retained.

Harvest date range at TPC (2024-2025): July 3 - Sept 25 (flowering and seed set greatly delayed in establishment year)

Recommended Harvest Method: combine 

Appendix B

Seed cleaning and storage

Cleaning process: Brush to free any seed remaining in capsules, then airscreen. Use the smallest sifting screen available (or a solid screen), check for seed in the sifting fraction and rescreen. It can be difficult to separate dust from the seed; adjust air and screen multiple times if needed. Eliminating the brushing step would likely produce less dust and improve purity of the final product with slight loss of yield.

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

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone NI (northern Iowa, in alignment 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.). Juncus dudleyi (Dudley's Rush). Minnesota Wildflowers. https://www.minnesotawildflowers.info/grass-sedge-rush/dudleys-rush  

Hilty, J. (2019). Dudley's Rush - Juncus dudleyi. Illinois Wildflowers. https://www.illinoiswildflowers.info/grasses/plants/dd_rush.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. 2025. 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.). Juncus dudleyi Wiegand, Dudley's rush. USDA plants database. https://plants.usda.gov/plant-profile/JUDU2

Species Guide Updated 12/18/2025

Carex hystericina Muhl. ex Willd. 

Alternate Common Name: porcupine sedge

Scientific Synonym: Carex hystricina Muhl. Rydberg.

Family: ‌sedge family (Cyperaceae)

Functional Group: sedges and rushes

Description 

Life cycle and growth form

Perennial with fibrous roots, forms clumps.

Height: 3/4 - 3 ft

Leaves and stem

Leaves in alternate, 3-ranked arrangement, hairless; basal sheaths are reddish purple and fibrous; culms are stiff and 3-sided, hairless, unbranched.

Flower, fruit and seedhead

Fruit/seedhead: Seed head consists of a terminal male spike and one to four prickly, cylindrical pistillate spikes, each containing 40-100 perigynia (seed containing structures).

Pollination: wind

Seed

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 30,000 seeds/oz (IA NRCS)

1000 seed weight: 0.48g (Seed Information Database)

Description: “Seeds” are 3-sided, ovate, brown achenes, wrapped in an inflated, distinctly veined perigynium with a long beak and two short teeth.

Typical seed test 

PLS: 87.48% (n=1)

Purity: 99.41% (n=1)

Germination: 62% (n=1)

Dormancy: 26% (n=1, determined by TZ)

(based on one test of a seedlot grown at TPC)

Habitat and range

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

Conservation status: Global- G5, secure; District of Columbia and Kentucky- SH, possibly extirpated; Maryland- S1, critically imperiled; California and Georgia- S2, imperiled; Arizona, Kansas, Washington, West Virginia, Illinois, and Wyoming- S3, vulnerable (NatureServe)

‌

General Comments

Sedges are a large, diverse group of grass-like plants that are important components of prairies, wetlands, and woodlands across our region. In Iowa alone, there are about 120 species of sedges. Grasshoppers and the larvae of skippers and other butterflies and moths feed on wetland sedge foliage, and their seeds are eaten by waterfowl and other birds. Sedges are notoriously difficult to identify to species. The prickly, cylindrical spikes of bottlebrush sedge are somewhat distinctive, but this species can be confused with longhair or bristly sedge (Carex comosa) which also occurs in our region and sallow sedge (Carex lurida) which is a state listed species in Iowa but is more common in neighboring states to the south and east. The development of stock seed by the Tallgrass Prairie Center in the early 2000s enabled broader access to reliably identified sedge species by native seed growers. As an obligate wetland species, bottlebrush sedge benefits from irrigation in production settings.

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: Benefits from cold-moist stratification for 30 days.

Sowing: Sow in germination flats or directly into plugs (2-3 seeds per cell), covering seed lightly (light improves germination of many sedge species); maintain even moisture until germination. Daytime temperatures should be around 70-80°F (22-27°C) and allowed to drop at night to 50-60°F (10-15°C). We have had good success planting into 2.5 in deep, 73-cell plug flats that are ridged to direct root development downward and have 3/4 in bottom openings to encourage root pruning and the formation of firmly rooted plugs for transplanting.

Transplanting: Seedlings are ready to transplant to the field about 10 weeks after sowing. 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.’

‌Appendix A

Stand management

Weeds: Plastic mulch reduces weed pressure in the first year or more. Holes in the plastic should be widened somewhat in subsequent years to allow the bunches to expand. Bunching plants are robust and leafy, competing well with many weeds; we have interplanted porcupine sedge with wetland forbs to provide support and reduce weed pressure.

Pests: None noted.

Diseases: None noted.

Soil moisture: Irrigation is recommended, though bottlebrush sedge may require less supplemental water than other wetland sedges. Drip tape can be applied under plastic mulch as planting beds are formed.

Seed production

First harvest: Plants produce a small amount of seed in the year following the transplant year. Peak harvest may be in the third year after transplanting.

Yield: At peak (3 years after planting), yields are around 445 lbs per acre (extrapolated from two production plots).

 

Stand life: Plants may be long-lived, but long-term yields are unknown.

Flowering date: June-July

Seed maturity/harvest date: Early to mid-July in northeast Iowa.

Seed retention: Seed begins to shatter in mid-July.

Harvest date range at TPC (2012-2024): June 26 - July 22

Recommended harvest method: Combine larger plantings. Hand harvest is effective for small plantings, and seed threshes easily from stems once dried.

Appendix B

Seed cleaning and storage

Cleaning process: Air-dry seed for two weeks or more after harvest. Pass material through a coarse screen (1/2 in hardware cloth) to remove larger stemmy material, if needed, then air screen.

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

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone IA

References

Carex hystericina (Porcupine Sedge). Minnesota Wildflowers. (n.d.). https://www.minnesotawildflowers.info/grass-sedge-rush/porcupine-sedge

Eggers, S. D., & Reed, D. M. (1997). Shallow Marshes. In Wetland Plants and Plant Communities of Minnesota and Wisconsin (2nd ed., p. 82). essay, U.S. Army Corps of Engineers, St. Paul District

Great Plains Flora Association. (1991). Sedge Family. In Flora of the Great Plains (2nd ed., p. 1080). University Press of Kansas.

Houseal, G. (2010). Plasticulture for seed production of wetland (Carex) species. Native Plants Journal, 11(1), 58-64. https://doi.org/10.2979/NPJ.2010.11.1.58   

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)]

Kettenring KM, Gardner G, Galatowitsch SM. Effect of light on seed germination of eight wetland Carex species. Ann Bot. 2006 Oct;98(4):869-74. doi: 10.1093/aob/mcl170. Epub 2006 Aug 11. PMID: 16905568; PMCID: PMC2806167.

Kettering, K.M. & Galatowitsch S.M. (2007) Temperature requirements for dormancy break and seed germination vary greatly among 14 wetland Carex species. Aquatic Botany, 87(3), 209 -220. https://doi.org/10.1016/j.aquabot.2007.06.003 

Mohlenbrock, R. H. (1999). Carex hystericina. In Illustrated Flora of Illinois - Sedges: Carex (p. 285). Southern Illinois University 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).. 

Porcupine Sedge. Illinois Wildflowers. (n.d.). https://www.illinoiswildflowers.info/grasses/plants/porc_sedge.htm

USDA NRCS National Plant Data Team. (n.d.). Carex hystericina Muhl. ex Willd.. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=CAHY4

Species Guide Updated 12/1/2025

Carex scoparia Schkuhr ex Willd.

Alternate Common Names: pointed broom sedge, lance-fruited oval sedge

Scientific Synonyms: Carex scoparia Schkuhr var. moniliformis Tuckerm., Carex scoparia Schkuhr var. condensa Fern.

Family: ‌sedge family (Cyperaceae)

Functional Group: sedges and rushes

Description 

Life cycle and growth form

perennial, fibrous rooted, short-rhizomatous, clump forming

Height: 1-2.5 ft  

Leaves and stem

Leaves flat and hairless with rough margins, alternate arrangement, 3-ranked, shorter than flowering stems; top of sheath around flowering stem (culm) has a ‘u’ or ‘v’ shaped notch, basal sheaths are brown and fibrous; culm is hairless and 3-sided, smooth and unbranched.

Flower, fruit and seedhead

Fruit/seedhead: 3-10 spikes per culm, each up to 2/3 in (10-15 mm) long, often crowded at the end of the culm but still distinct as individual elliptical to oval spikes; golden-tan color at maturity, stem may bend or arch at the tip or be straight.

Pollination: wind

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 84,000 seeds/oz (IA NRCS)

1000 seed weight: 0.44g (Seed Information Database)

Description: “seed” is an ovate to elliptic, brown achene that is enclosed in a perigynium; perigynium is golden-tan, flat, and hairless, 5-veined on each side, lance-shaped and often 3-4 times as long as wide.

Typical seed test 

PLS: 93% (n = 5)

Purity: 96% (n = 5)

Germination: 50% (n = 3)

Dormancy: 66% (n = 5)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Moist to wet soil; partial to full sun; prairies, shorelines, swales, fens, seeps, marshes, ditches; Wetland Indicator Status is Facultative Wetland (FACW) for the Midwest.

Conservation status: Global- G5, secure; North Dakota- SH, possibly extirpated; Arkansas, Utah, and Wyoming- S1, critically imperiled; Montana- S1/S2, critically imperiled to imperiled; Georgia- S3, vulnerable (NatureServe) 

‌

General Comments

Sedges are a large, diverse group of grass-like plants that are important components of prairies, wetlands, and woodlands across our region. In Iowa alone, there are about 120 species of sedges. Grasshoppers and the larvae of skippers and other butterflies and moths feed on sedge foliage, and their seeds are eaten by grassland birds and waterfowl. They are notoriously difficult to identify to species, especially the oval sedges to which broom sedge belongs. The development of stock seed by the Tallgrass Prairie Center in the early 2000s enabled broader access to reliably identified sedge species by native seed growers. Broom sedge is found naturally in moist to wet soils and may benefit from supplemental watering in seed production systems.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

We do not recommend direct seeding for this species.

 

‌‌Greenhouse

Seed pre-treatment: Benefits from cold-moist stratification for 30 days.

Sowing: Sow in germination flats or directly into plugs (2-3 seeds per cell), covering seed lightly (light improves germination of many sedge species); maintain even moisture until germination. Daytime temperatures should be around 70-80°F (22-27°C) and allowed to drop at night to 50-60°F (10-15°C). We have had good success planting into 2.5 in deep, 73-cell plug flats that are ridged to direct root development downward and have 3/4 in bottom openings to encourage root pruning and the formation of firmly rooted plugs for transplanting.

Transplanting: Seedlings are ready to transplant to an irrigated field about 10 weeks after sowing. 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.’

‌Appendix A

Stand management

Weeds: Plastic mulch reduces weed pressure in the first year or more. Holes in the plastic should be widened somewhat in subsequent years to allow the bunches to expand. Bunching plants are robust and leafy, competing well with many weeds; we have interplanted broom sedge with cardinalflower to provide support and reduce weed pressure (note: interplanting necessitates hand harvest of the sedge and eliminates broadleaf herbicides as an option). In large-scale production systems or those where the use of weed barriers and/or hand weeding is not practical, herbicides (e.g., broad-leaf herbicides and/or pre-emergents) may be useful to prevent weeds from competing with the sedge plants and/or complicating the seed cleaning process. Significant weed problems may be caused by winter annuals (e.g., members of the mustard family), other small-seeded broad-leaf annuals, and annual grasses (e.g., downy brome).  Herbicide applications should be timed to most effectively control specific weeds and minimize damage to the sedge plants. Care must be taken to read affected “weed” lists, as sedges are considered weeds in crop systems. Always read and follow label instructions.

Pests: None noted.

Diseases: None noted.

Soil moisture: Irrigation is recommended. Drip tape can be applied under plastic mulch as planting beds are formed.

Seed production

First harvest: First harvest one year after transplanting

Yield/acre: 190-290 pounds per acre (extrapolated from cleaned seed harvested from two plots at TPC)

Stand life: Unknown, but plants are likely long-lived and should continue to be productive with proper weed management.

Flowering date: June

Seed maturity/Harvest date: Late June to early July in northeastern Iowa

Seed retention: Moderate risk of shattering at maturity; also vulnerable to lodging, potentially complicating combine harvest.

Harvest date range at TPC (2010-2023): June 28 - July 3

Recommended harvest method: We have harvested small plots using hand sickles; seed threshes easily after drying on tarps. Combining should also work well, if seed is mature.

Appendix B

Seed cleaning and storage

Cleaning process: Air-dry seed for two weeks or more after harvest. Pass material through a coarse screen (1/2 in hardware cloth) to remove larger stemmy material, if needed, then air screen.

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

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone IA

References

Carex scoparia (Pointed Broom Sedge). Minnesota Wildflowers. (n.d.). https://www.minnesotawildflowers.info/grass-sedge-rush/pointed-broom-sedge

Houseal, G. (2010). Plasticulture for seed production of wetland (Carex) species. Native Plants Journal, 11(1), 58-64. https://doi.org/10.2979/NPJ.2010.11.1.58   

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)]

Kettenring and Galatowitsch (2007) https://www.sciencedirect.com/science/article/pii/S030437700700085X

Kettenring KM, Gardner G, Galatowitsch SM. Effect of light on seed germination of eight wetland Carex species. Ann Bot. 2006 Oct;98(4):869-74. doi: 10.1093/aob/mcl170. Epub 2006 Aug 11. PMID: 16905568; PMCID: PMC2806167.

Mohlenbrock, R. H. (1999). Carex scoparia. In Illustrated Flora of Illinois - Sedges: Carex (p. 108). Southern Illinois University Press. 

Murphy, M. & Spyreas, G. & Marcum, P. (2025) Carex of Illinois & Surrounding States: The Oval Sedges. University of Illinois 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).

Pointed Broom Sedge. Illinois Wildflowers. (n.d.). https://www.illinoiswildflowers.info/grasses/plants/pb_sedge.htm

USDA NRCS National Plant Data Team. (n.d.). Carex scoparia Schkuhr ex Willd.. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=CASC11

Species Guide Updated 2/7/2025

Carex molesta, Mack. ex Bright 

Alternate Common Names: field oval sedge, pest sedge

Family: ‌sedge family (Cyperaceae)

Functional Group: sedges and rushes

Description 

Life cycle and growth form

Perennial, clump-forming (cespitose) sedge, with fibrous roots.

Height: 1-3 ft  

Leaves and stem

Leaves flat and hairless with rough margins, 1.5-4 (less than 1/4 in) mm wide, shorter than flowering stalks; top of sheath is ‘u’ or ‘v’ shaped and white, base of sheath is brown and somewhat fibrous; flowering culms are hairless and 3-sided.

Flower, fruit and seedhead

Flower: Tiny greenish flowers are clustered into 2-5 nearly globular spikes, each about 1/3 in long, at the tip of a culm.

Fruit/seed head: Spikes mature to clusters of achenes, each wrapped in a perigynium, separated by delicate pistillate scales.

Pollination: Wind

Note: There are several excellent guides to the sedges of the Upper Midwest region, and it is worth having a selection of them on your bookshelf to use as references, as questions about the identity of sedges often arise, even in carefully planted production fields. This description is intended as an introduction, not a complete, definitive guide.

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 25,000 (IA NRCS)

1000 seed weight: 1.11g (Seed Information Database)

Description: “Seed” is a two-sided achene, brown, elliptic, 0.9-1.3 mm wide and 1.3-1.7 mm long, enclosed in a flattened, ovate, brown to greenish perigynium, 1.8-3 mm wide and 3.3-5 mm long, with a beak (0.7-1.6 mm long) and pale, flattened wing.

Typical seed test 

PLS: 93% (n = 11)

Purity: 98% (n = 11)

Germination: 29% (n = 9)

Dormancy: 57% (n = 9)

(averages obtained from n tests of purchased seed lots)

Habitat and range

‌Habitat: Dry to wet soil; partial to full sun; prairies, meadows, swamps, thickets, woodland edges and floodplains, river banks, ditches; Wetland Indicator Status is Facultative (FAC) for the Midwest; mesic to wet-mesic soils are recommended for seed production.

Conservation status: Global- G5, secure; New Hampshire- SH, possibly extirpated; Connecticut, Illinois, Massachusetts, and Vermont- S1, critically imperiled; New Jersey and West Virginia- S2/S3, imperiled to vulnerable; Kansas- S3, vulnerable; in all other states within its natural range, status is S4 (apparently secure) to S5 (secure) or unranked (NatureServe). 

General Comments

Sedges are a large, diverse group of grass-like plants that are important components of prairies, wetlands, and woodlands across our region. In Iowa alone, there are about 120 species of sedges. Grasshoppers and the larvae of skipper butterflies, among other insects, feed on sedge foliage, and their seeds are eaten by grassland birds. Troublesome sedge is easy to propagate for seed production and reliably establishes from seed in prairie plantings. This species has a wide tolerance for soil moisture variation and persists in areas with some disturbance. Sedges are notoriously difficult to identify to species, especially the oval sedges, the section to which troublesome sedge belongs. The development of stock seed by the Tallgrass Prairie Center in the early 2000s enabled broader access to reliably identified sedge species by native seed growers.

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: 30 days cold-moist stratification

Sowing: Sow in germination flats or directly into plugs (2-3 seeds per cell), covering seed lightly (light improves germination of many sedge species); maintain even moisture until germination. Daytime temperatures should be around 70-80°F (22-27°C) and allowed to drop at night to 50-60°F (10-15°C). We have had good success planting into 2.5 in deep, 73-cell plug flats that are ridged to direct root development downward and have 3/4 in bottom openings to encourage root pruning and the formation of firmly rooted plugs for transplanting. 

Transplanting: Seedlings are ready to transplant to the field about 10 weeks after sowing. 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.’ Transplant into prepared plasticulture rows at 8-12 inch spacing.

‌Appendix A

Stand management

Weeds: Plastic mulch reduces weed pressure in the first year or more. Holes in the plastic should be widened somewhat in subsequent years to allow the bunches to expand. In large-scale production systems or those where the use of weed barriers and/or hand weeding is not practical, herbicides (e.g., broad-leaf herbicides and/or pre-emergents) may be useful to prevent weeds from competing with the sedge plants and/or complicating the seed cleaning process. Significant weed problems may be caused by winter annuals (e.g., members of the mustard family), other small-seeded broad-leaf annuals, and annual grasses (e.g., downy brome).  Herbicide applications should be timed to most effectively control specific weeds and minimize damage to the sedge plants. Care must be taken to read affected “weed” lists, as sedges are considered weeds in crop systems. Always read and follow label instructions.

Pests: None noted.

Diseases: None noted.

Seed production

First harvest: First harvest is the year after transplanting.

Yield/acre: 100 to 380 pounds per acre (extrapolated from harvests of three plots)

Stand life: Stands remain productive for several years. We have seen a decline in production in some plots in their sixth year. Plots were retired from production after the sixth year, so it is uncertain whether or not they would have remained productive in the longer term.

Flowering date: June in northern Iowa

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

Seed retention: Moderate risk of shattering. Ironically, the tendency of this species to lodge may protect somewhat against seed shatter.

Harvest date range at TPC (2008-2012): June 26 - July 18 

Recommended harvest method: Combining is the most efficient method. However, lodging can be problematic, and we have hand harvested a badly lodged plot growing in wet-mesic soils after an exceptionally wet spring season. 

Appendix B

Seed cleaning and storage

Cleaning process: Air-dry seed for two weeks or more after harvest. For hand-harvested material, thresh seed from dried stalks by beating with rakes or forks, then treat similarly to combined material. Pass material through a coarse screen (1/2 in hardware cloth) to remove larger stemmy material, if needed, then air screen. If perigynia removal is desired, pass material through a brush machine with medium bristles before air screening. (Note: perigynia removal destroys several characteristics used in identification.)

Seed storage: cool/dry (33-50° F, 30-50% RH); seed may retain high viability for over 10 years under these conditions.

Appendix C

Released Germplasm 

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

References

Boeck Crew, C.M., Myers, M.C., Sherrard, M.E., Elgersma, K.J., Houseal, G.A., & Smith D.D. (2020). Stratification and perigynia removal improve total germination and germination speed in 3 upland prairie sedge species. Native Plants Journal, 21(2), 120-131. https://doi.org/10.3368/npj.21.2.120 

Chayka, K. (n.d.). Carex molesta (Troublesome Sedge). Minnesota Wildflowers. (n.d.). https://www.minnesotawildflowers.info/grass-sedge-rush/troublesome-sedge 

Cochrane, T. S., Elliot, K., & Lipke, C. S. (2014). Field Oval Sedge. In Prairie Plants of the University of Wisconsin-Madison Arboretum (3rd ed., p. 163). essay, University of Wisconsin-Madison Arboretum.

Hilty, J. (2019). Troublesome Sedge. Illinois Wildflowers. https://www.illinoiswildflowers.info/grasses/plants/trouble_sedge.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)]

Mohlenbrock, R. H. (1999). Carex bicknellii. In Illustrated Flora of Illinois - Sedges: Carex (p. 139). Southern Illinois University Press.

Murphy, M. & Spyreas, G. & Marcum, P. (2025) Carex of Illinois & Surrounding States: The Oval Sedges. University of Illinois 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).

Smith, W.R. (2018) Sedges and Rushes of Minnesota: The Complete Guide to Species Identification. University of Minnesota Press. 

USDA NRCS National Plant Data Team. (n.d.). Carex molesta Mack. ex Bright. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=CAMO11

Species Guide Updated 1/5/2026

Scirpus cyperinus, (L.) Kunth 

Alternate Common Names: common woolsedge, woolgrass bulrush, cottongrass bulrush

Scientific Synonyms: Scirpus cyperinus (L.) Kunth var. condensatus Fernald, Scirpus cyperinus (L.) Kunth var. eriophorum (Michx.) Kunth, Scirpus cyperinus (L.) Kunth var. laxus (A. Gray) Beetle, Scirpus cyperinus (L.) Kunth var. pelius Fernald, Scirpus cyperinus (L.) Kunth var. rubricosus (Fernald) Gilly, Scirpus eriophorum Michx., Scirpus rubricosus Fernald, Scirpus cyperinus (L.) Kunth var. andrewsii (Fernald) Fernald, Eriophorum cyperinum L.

Family: ‌sedge family (Cyperaceae)

Functional Group: sedges and rushes

Description 

Life cycle and growth form

Perennial with short rhizomes, forming dense, leafy clumps with tall flowering culms.

Height: 3-6 ft 

Leaves and stem

Leaves grass-like; flowering stems are smooth, round to subtly 3-sided, and sturdy; old leaves accumulate to form tussocks.

Flower, fruit and seedhead

Flower/fruit/seed head: Clusters of 3-7 egg-shaped spikelets (each 1/3 in long) at the ends of slender branches in nodding, compound panicles 3-6 in long; spikelets are grayish green when in flower but mature to reddish brown; curly hairs on seeds expand when mature, making ripe seedheads look wooly.

Pollination: Wind

Seed

 

Appendix D

‌Seed characteristics 

Seed weight: 

Seeds per ounce: 1,700,000 (IA NRCS)

1000 seed weight: 0.04g (Seed Information Database)

Description:  “Seeds” are achenes that are 3-sided, oval-elliptical, pale gold, and tiny (less than 1 mm long and 0.5 mm wide). There is a tuft of wooly hairs at the base of each achene.

Typical seed test 

PLS: 91%

Purity: 99%

Germination: 0%

Dormancy: 0%

(averages obtained from 1 tests of purchased seed lots)

Habitat and range

‌Habitat: Moist to wet soil; partial to full sun; marshes, shorelines, swamps, seeps, sedge meadows, pond edges, ditches; Wetland Indicator Status is Obligate Wetland (OBL) for the Midwest; irrigation is needed for seed production.

Conservation status: Global- G5, secure; Nebraska- S1, critically imperiled; Kansas and Wyoming- S2, imperiled; Idaho and Montana- S3, vulnerable; in all other states within its natural range, status is S4 (apparently secure) to S5 (secure) or unranked (NatureServe). 

General Comments

The combination of wooly seedheads and clustered spikelets help distinguish woolgrass from similar bulrushes in the genus Scirpus. The robust, tussocky clumps of woolgrass protect soil from erosion in the wetlands and ditches where it thrives. Its leaves, stems, and seedheads provide food and nesting sites for waterfowl and other wildlife. This species is not difficult to propagate from seed, and grows well under irrigation, but the wooly hairs around its “seeds” (achenes) present some challenges for seed harvest and cleaning.

Recommendations for Seed Production 

Establishment for seed production

‌Direct seeding

Not recommended for this species.

 

‌‌Greenhouse

Seed pre-treatment: Cold/moist stratification for 30 days.

Sowing: About 3 months before the last frost, surface sow in germination flats (our preferred method) or directly into plugs. Aim for 2-3 seeds per cell, but this can be difficult to judge with such tiny seeds. In either type of container, use caution when watering to avoid splashing seed from the soil surface. Seedlings are extremely tiny but fast growing. If started in germination flats, they can be dibbled into plugs using forceps.

Transplanting: When seedlings have grown into well-rooted plugs, move them outside to harden off, then transplant into irrigated, plasticulture rows at 12 inch spacing.

‌Appendix A

Stand management

Weeds: Prepare clean, weed-free beds and use plastic mulch to suppress weeds in the establishment year. Plants are robust and leafy, suppressing many weeds. Mow or cultivate between rows. Hand rogue to remove problematic weeds.

Pests: None noted.

Diseases: None noted.

Seed production

First harvest: Plants flower and set seed the year after planting.

Yield/acre: 40-60 pounds per acre (extrapolated from harvests of two production plots at TPC)

Stand life: Plants are likely long-lived, but we have not yet maintained plots for longer than three years. Yield from one plot declined from year 2 to year 3, and the plot was retired. 

Flowering date: June in northern Iowa

Seed maturity/Harvest date: mid to late August in northern Iowa (the first harvest may occur later than normal) 

Seed retention: Moderate risk of shattering when seedheads become “wooly.”

Harvest date range at TPC (2011-2025): August 14 - August 25 

Recommended harvest method: Hand pick early maturing plants, then combine. We have had issues with the wooly hairs causing clumps to form on the combine sieves and pass out with the straw. We collected that material and passed it through a stationary combine to extract more seed. 

Appendix B

Seed cleaning and storage

Cleaning process: Brush with soft bristles to help break the wooly bristles from the achenes, then airscreen.

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

Appendix C

Released Germplasm 

Source Identified material: Natural Selections/Iowa Ecotype Zone Iowa

References

Chayka, K. (n.d.). Scirpus cyperinus (woolgrass). Minnesota Wildflowers. https://www.minnesotawildflowers.info/grass-sedge-rush/woolgrass 

Hilty, J. (2019). Wool grass - Scirpus cyperinus. Illinois Wildflowers. https://www.illinoiswildflowers.info/grasses/plants/wool_grass.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).

Schultz, Jan; Beyer, Patty; Williams, Julie. 2001. Propagation protocol for production of Container (plug) Scirpus cyperinus (L.) Kunth plants USDA FS - Hiawatha National Forest Marquette, Michigan. In: Native Plant Network. URL: https://NativePlantNetwork.org (accessed 2026/01/05). US Department of Agriculture, Forest Service, National Center for Reforestation, Nurseries, and Genetic Resources.

USDA NRCS National Plant Data Team. (n.d.). Scirpus cyperinus (L.) Kunth. USDA plants database. https://plants.usda.gov/home/plantProfile?symbol=SCCY  

Whittemore, A. T. & Shuyler, A. E. (2020, November 5). Scirpus cyperinus (Linnaeus) Kunth. Flora of North America. http://floranorthamerica.org/Scirpus_cyperinus

Species Guide Updated 1/5/2026