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Index / Search / Polygonum hydropiper

§1 Plant

Polygonum hydropiper L.

vernacular marshpepper knotweed — species · Polygonaceae

USDA
POHY
GBIF
6391194 syn.
Rank
species
marshpepper knotweed (Polygonum hydropiper)
Platephotograph · Sam Wahl source · iNaturalist ↗

§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

· 888 counties across 43 states/territories
Legend Native · 0 Introduced · 888 Both · 0 Hover a county for detail.

§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 888 counties across 43 states/territories.

Alabama view state ↗ 1 I ▾
Arkansas view state ↗ 9 I ▾
California view state ↗ 18 I ▾
Colorado view state ↗ 3 I ▾
Delaware view state ↗ 1 I ▾
District of Columbia view state ↗ 1 I ▾
Georgia view state ↗ 6 I ▾
Idaho view state ↗ 9 I ▾
Illinois view state ↗ 75 I ▾
Indiana view state ↗ 40 I ▾
Iowa view state ↗ 17 I ▾
Kansas view state ↗ 29 I ▾
Kentucky view state ↗ 11 I ▾
Louisiana view state ↗ 2 I ▾
Maine view state ↗ 15 I ▾
Massachusetts view state ↗ 13 I ▾
Michigan view state ↗ 43 I ▾
Minnesota view state ↗ 47 I ▾
Mississippi view state ↗ 1 I ▾
Missouri view state ↗ 40 I ▾
Montana view state ↗ 8 I ▾
Nebraska view state ↗ 19 I ▾
Nevada view state ↗ 1 I ▾
New Hampshire view state ↗ 10 I ▾
New Jersey view state ↗ 18 I ▾
New York view state ↗ 56 I ▾
North Carolina view state ↗ 31 I ▾
North Dakota view state ↗ 13 I ▾
Ohio view state ↗ 56 I ▾
Oklahoma view state ↗ 14 I ▾
Oregon view state ↗ 21 I ▾
Pennsylvania view state ↗ 64 I ▾
Rhode Island view state ↗ 4 I ▾
South Carolina view state ↗ 1 I ▾
South Dakota view state ↗ 3 I ▾
Tennessee view state ↗ 20 I ▾
Utah view state ↗ 4 I ▾
Vermont view state ↗ 13 I ▾
Virginia view state ↗ 50 I ▾
Washington view state ↗ 16 I ▾
West Virginia view state ↗ 22 I ▾
Wisconsin view state ↗ 62 I ▾
Wyoming view state ↗ 1 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-2026-05-26

fetched 2026-05-26T20:46:58Z