Wildflower (forb) · Polygonaceae
Pennsylvania smartweed
Polygonum pensylvanicum
Pennsylvania smartweed is recorded as native to 46 states and territories in Kew’s World Checklist of Vascular Plants and USDA PLANTS, and recorded in 1,684 counties of those states by USDA PLANTS.
Key facts · USDA PLANTS
Pennsylvania smartweed at a glance
- Native in
- 1,684 counties, across 46 states and territories
- Estimated cold hardiness
- Zone 10b PLANTS minimum temperature 32°F
- Mature height
- 3.9 ft PLANTS mature height
- Light and water
- Full sun (shade-intolerant) Medium water use
Estimated cold hardiness: zone 10b. PLANTS gives a minimum temperature of 32°F; zone 10b winters bottom out at 35°F, the coldest half-zone that stays within that limit.
Pennsylvania smartweed is recorded as native to 46 states and territories in Kew’s World Checklist of Vascular Plants and USDA PLANTS, and recorded in 1,684 counties of those states by USDA PLANTS.
Counties where it is native
The 15 counties with the most ZIP codes among the 1,684 where it is listed.
Native counties by state
- Alabama 7 counties
- Alaska 6 counties
- Arizona 5 counties
- Arkansas 55 counties
- California 7 counties
- Colorado 16 counties
- Connecticut statewide record
- Delaware 3 counties
- District of Columbia 1 county
- Florida 19 counties
- Georgia 19 counties
- Illinois 102 counties
- Indiana 79 counties
- Iowa 28 counties
- Kansas 103 counties
- Kentucky 71 counties
- Louisiana 59 counties
- Maine 12 counties
- Maryland 1 county
- Massachusetts 14 counties
- Michigan 34 counties
- Minnesota 55 counties
- Mississippi 39 counties
- Missouri 102 counties
- Montana 1 county
- Nebraska 58 counties
- Nevada 3 counties
- New Hampshire 10 counties
- New Jersey 20 counties
- New Mexico 4 counties
- New York 50 counties
- North Carolina 87 counties
- North Dakota 15 counties
- Ohio 81 counties
- Oklahoma 39 counties
- Pennsylvania 64 counties
- Rhode Island 5 counties
- South Carolina 36 counties
- South Dakota 26 counties
- Tennessee 61 counties
- Texas 82 counties
- Vermont 11 counties
- Virginia 90 counties
- West Virginia 39 counties
- Wisconsin 62 counties
- Wyoming 3 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
- Annual
- Mature height
- 3.9 ft
- Growth rate
- Moderate
- Growth form
- Single Crown
- Shape
- Erect
- Lifespan
- Not recorded
- Active growth period
- Summer
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
- 12 to 60 in per year
Soil
- Soil textures
- Coarse, medium and fine
- pH range
- 4 to 8.5
- Lime (CaCO₃) tolerance
- Medium
- Salinity tolerance
- Low
- Fertility requirement
- Medium
- Minimum root depth
- 14 in
Climate
- Minimum temperature
- 32°F
- Estimated cold hardiness
- Zone 10b and warmer
- Minimum frost-free days
- 95
- Fire tolerance
- High
Flowers, leaves and fruit
- Flower color
- Red
- Showy flowers
- Yes
- Bloom period
- Spring
- Foliage color
- Green
- Showy in fall
- No
- Keeps leaves
- No
- Fruit color
- Black
Other
- Toxicity
- None
- Nitrogen fixation
- None
- Nursery availability
- Routinely Available
- Family
- Polygonaceae
- PLANTS symbol
- POPE2
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
- Polygonum pensylvanicum (PLANTS symbol POPE2).
- 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