Grass or grass-like · Juncaceae
Knotted rush
Juncus nodosus · includes its varieties and subspecies
Knotted rush is recorded as native to 31 states and territories in Kew’s World Checklist of Vascular Plants and USDA PLANTS, and recorded in 480 counties of those states by USDA PLANTS.
Key facts · USDA PLANTS
Knotted rush at a glance
- Native in
- 480 counties, across 31 states and territories
- Estimated cold hardiness
- Zone 4b PLANTS minimum temperature −28°F
- Mature height
- 2 ft PLANTS mature height
- Light and water
- Full sun (shade-intolerant) Medium water use
Estimated cold hardiness: zone 4b. PLANTS gives a minimum temperature of −28°F; zone 4b winters bottom out at −25°F, the coldest half-zone that stays within that limit.
Knotted rush is recorded as native to 31 states and territories in Kew’s World Checklist of Vascular Plants and USDA PLANTS, and recorded in 480 counties of those states by USDA PLANTS.
Counties where it is native
The 15 counties with the most ZIP codes among the 480 where it is listed.
Native counties by state
- California 3 counties
- Colorado 12 counties
- Connecticut statewide record
- Idaho 13 counties
- Illinois 25 counties
- Indiana 11 counties
- Iowa 7 counties
- Maine 8 counties
- Massachusetts 6 counties
- Michigan 61 counties
- Minnesota 60 counties
- Missouri 1 county
- Montana 12 counties
- Nebraska 24 counties
- Nevada 5 counties
- New Hampshire 5 counties
- New Jersey 5 counties
- New Mexico 4 counties
- New York 41 counties
- North Dakota 24 counties
- Ohio 15 counties
- Pennsylvania 20 counties
- South Dakota 8 counties
- Texas 3 counties
- Utah 10 counties
- Vermont 14 counties
- Virginia 2 counties
- Washington 5 counties
- West Virginia 9 counties
- Wisconsin 56 counties
- Wyoming 11 counties
Growing traits
Values from the PLANTS characteristics record. “Not recorded” means PLANTS has no value; nothing here is estimated except the zone.
Growth
- Growth habit
- Graminoid
- Duration
- Perennial
- Mature height
- 2 ft
- Growth rate
- Moderate
- Growth form
- Single Stem
- Shape
- Erect
- Lifespan
- Long
- Active growth period
- Spring
Light and water
- Shade tolerance
- Intolerant (full sun (shade-intolerant))
- Moisture use
- Medium water use
- Drought tolerance
- Medium
- Tolerance of waterlogged soil
- Medium
- Precipitation range
- 35 to 50 in per year
Soil
- Soil textures
- Coarse, medium and fine
- pH range
- 4 to 7.5
- Lime (CaCO₃) tolerance
- Medium
- Salinity tolerance
- None
- Fertility requirement
- Medium
- Minimum root depth
- 18 in
Climate
- Minimum temperature
- −28°F
- Estimated cold hardiness
- Zone 4b and warmer
- Minimum frost-free days
- 150
- Fire tolerance
- Medium
Flowers, leaves and fruit
- Flower color
- Green
- Showy flowers
- No
- Bloom period
- Summer
- Foliage color
- Dark Green
- Showy in fall
- No
- Keeps leaves
- No
- Fruit color
- Brown
Other
- Toxicity
- None
- Nitrogen fixation
- None
- Nursery availability
- Routinely Available
- Family
- Juncaceae
- PLANTS symbol
- JUNO2
Source & data date
- Source
- USDA NRCS PLANTS Database: county distribution records, native status and plant characteristics. CC0 (public domain dedication, per the data.gov catalog record).
- Kew’s World Checklist of Vascular Plants (WCVP): native or introduced status by state. CC BY 3.0.
- USGS US-RIIS (ver. 2.0): species listed as introduced are excluded. CC0.
- Citation
- USDA, NRCS. 2026. The PLANTS Database (https://plants.usda.gov, 11/04/2026). National Plant Data Team, Greensboro, NC USA.
- Govaerts R. (ed.) (2026). WCVP: World Checklist of Vascular Plants. Facilitated by the Royal Botanic Gardens, Kew. Data file dated 2026-06-04, http://sftp.kew.org/pub/data-repositories/WCVP/ (retrieved 2026-11-04). Paper: Govaerts R. et al. (2021) The World Checklist of Vascular Plants, a continuously updated resource for exploring global plant diversity. Scientific Data 8, 215.
- Data date
- Retrieved from PLANTS on November 4, 2026; WCVP data file dated June 4, 2026.
- Scope
- Juncus nodosus (PLANTS symbol JUNO2), including 1 variety or subspecies folded into the species.
- Method
- A species is listed when it is recorded as native to the state in Kew’s World Checklist of Vascular Plants and USDA PLANTS, and recorded in the county by USDA PLANTS. Species PLANTS labels both native and introduced are listed separately. Full method · All sources