Index / Search / Polygonum hydropiper
§1 Plant
Polygonum hydropiper L.
vernacular marshpepper knotweed — species · Polygonaceae
§2Habit & range
Habit and range
- Growth habit
- Forb/herb
- Duration
- Annual
- Group
- Dicot
- Family
- Polygonaceae Juss.
- Genus
- Polygonum
§2a
Native status, by region
- AK Alaska Introduced
- CAN Canada Introduced
- HI Hawaii Introduced
- L48 Lower 48 States Introduced
- SPM St. Pierre & Miquelon Introduced
§2b
County-level range
· 12 counties across 2 states/territories§3Cultivation specs · USDA
Recorded by the USDA Plant Materials Program.
§3a
Tolerances
- Drought
- None
- Shade
- High
- Moisture use
- High
- Fire
- None
- Salinity
- None
- Anaerobic
- Low
- CaCO₃
- Low
- Hedging
- None
§3b
Climate & soil
- Cold tolerance
- 52 °F minimum
- Frost-free days
- 120 min.
- Precipitation
- 24–60 in/yr
- pH range
- 5–7.5
- Root depth
- 6 in min.
- Fertility need
- Medium
- Soil texture
- coarse, medium, fine
§3c
Form & growth
- Growth form
- Single Crown
- Growth rate
- Rapid
- Mature height
- 1.6 ft
- Foliage texture
- Medium
- Foliage colour
- Green
- Porosity (summer)
- Moderate
- Porosity (winter)
- Porous
- Flower colour
- Red
- Fruit colour
- Black
- Fire resistant
- No
- N fixation
- None
- Toxicity
- None
§3d
Reproduction
- Bloom period
- Late Spring
- Seed abundance
- High
- Seed begins
- Summer
- Seed ends
- Fall
- Spread rate
- Moderate
- Stratify
- No
- Seeds / lb
- 275,000
- Propagation
- seed
§3e
Use & availability
- Commercial availability
- Routinely Available
- Nursery stock
- No
- Palatable, human
- No
- Lumber
- No
- Christmas tree
- No
§4Counties, by state
Recorded in 12 counties across 2 states/territories.
Montana view state ↗ 8 I ▾
Rhode Island view state ↗ 4 I ▾
§5Sources & provenance
USDA PLANTS
Symbol, taxonomy, distribution, cultivation specs, native status. Public domain.
plants.usda.gov/POHY ↗GBIF Backbone
Canonical taxonomic identity, synonym resolution, cross-refs. CC0.
gbif.org/species/6391194 ↗Record version
Cached and built locally. Source version on this record:
usda-plants-mt-2026-05-25
fetched 2026-05-25T18:27:19Z