Wildflower (forb) · Onagraceae
Bog willowherb
Epilobium leptophyllum
Bog willowherb is recorded as native to 37 states and territories in Kew’s World Checklist of Vascular Plants and USDA PLANTS, and recorded in 422 counties of those states by USDA PLANTS.
Key facts · USDA PLANTS
Bog willowherb at a glance
- Native in
- 422 counties, across 37 states and territories
- Estimated cold hardiness
- Zone 4a PLANTS minimum temperature −33°F
- Mature height
- 3.6 ft PLANTS mature height
- Light and water
- Sun to part shade High water use
Estimated cold hardiness: zone 4a. PLANTS gives a minimum temperature of −33°F; zone 4a winters bottom out at −30°F, the coldest half-zone that stays within that limit.
Bog willowherb is recorded as native to 37 states and territories in Kew’s World Checklist of Vascular Plants and USDA PLANTS, and recorded in 422 counties of those states by USDA PLANTS.
Counties where it is native
The 15 counties with the most ZIP codes among the 422 where it is listed.
Native counties by state
- Alaska 1 county
- California 1 county
- Colorado 6 counties
- Connecticut statewide record
- Idaho 1 county
- Illinois 13 counties
- Iowa 2 counties
- Kansas 5 counties
- Maine 13 counties
- Maryland 3 counties
- Massachusetts 14 counties
- Michigan 45 counties
- Minnesota 59 counties
- Missouri 1 county
- Montana 4 counties
- Nebraska 13 counties
- Nevada 1 county
- New Hampshire 6 counties
- New Jersey 7 counties
- New Mexico 1 county
- New York 41 counties
- North Carolina 2 counties
- North Dakota 25 counties
- Ohio 19 counties
- Oklahoma 1 county
- Oregon 2 counties
- Pennsylvania 32 counties
- Rhode Island 2 counties
- South Dakota 7 counties
- Tennessee 2 counties
- Utah 5 counties
- Vermont 5 counties
- Virginia 6 counties
- Washington 2 counties
- West Virginia 7 counties
- Wisconsin 64 counties
- Wyoming 4 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
- Forb/herb
- Duration
- Perennial
- Mature height
- 3.6 ft
- Growth rate
- Slow
- Growth form
- Single Stem
- Shape
- Erect
- Lifespan
- Moderate
- Active growth period
- Spring
Light and water
- Shade tolerance
- Intermediate (sun to part shade)
- Moisture use
- High water use
- Drought tolerance
- Low
- Tolerance of waterlogged soil
- High
- Precipitation range
- 15 to 50 in per year
Soil
- Soil textures
- Medium and fine
- pH range
- 4 to 6.5
- Lime (CaCO₃) tolerance
- Low
- Salinity tolerance
- None
- Fertility requirement
- Low
- Minimum root depth
- 10 in
Climate
- Minimum temperature
- −33°F
- Estimated cold hardiness
- Zone 4a and warmer
- Minimum frost-free days
- 80
- Fire tolerance
- None
Flowers, leaves and fruit
- Flower color
- Red
- Showy flowers
- Yes
- Bloom period
- Summer
- Foliage color
- Green
- Showy in fall
- No
- Keeps leaves
- No
- Fruit color
- Brown
Other
- Toxicity
- None
- Nitrogen fixation
- None
- Nursery availability
- No Known Source
- Family
- Onagraceae
- PLANTS symbol
- EPLE2
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
- Epilobium leptophyllum (PLANTS symbol EPLE2).
- 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