knotweed, smartweed, tearthumb
7 species
1 subspecies and varieties
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Persicaria amphibiawater smartweed
Distribution: Widely distributed on both sides of the Cascades crest in Washington; Alaska to California, east to the Atlantic Coast.
Habitat: River, stream, lake, and pond margins in water to 2 meters deep to adjacent moist uplands.
Origin: Native
Flowers: July-October
Persicaria hydropipersmartweed, mild water-pepper
Distribution: Introduced weed found in much of North America and throughout the Pacific Northwest.
Habitat: Swamps, ditches, and other wet places, mostly at low elevations.
Origin: Introduced
Flowers: July - September
Persicaria hydropiperoideswater pepper, swamp smartweed
Distribution: Chiefly west of the Cascades in Washington; British Columbia south to Mexico and South America, east across North America to the Atlantic coast.
Habitat: Moist to swampy areas, often growing in mud, from the lowlands to the lower mountain valleys.
Origin: Native
Flowers: July-September
Persicaria lapathifoliadock-leaf smartweed, pale smartweed, willow weed
Distribution: Widely distributed throughout Washington; widely distributed throughout all of North America.
Habitat: Streambanks, pond and lakeshores and other wet places.
Origin: Native
Flowers: May-September
Persicaria maculosaheartweed, lady's-thumb, spotted lady's-thumb, redshank
Distribution: Occurring throughout much of Washington; widely distributed throughout North America.
Habitat: A weedy species, usually on moist, cultivated or otherwise disturbed soil.
Origin: Introduced
Flowers: March-September
Persicaria punctatadotted knotweed, dotted smartweed, water smartweed
Distribution: Occurring mostly in south-central Washington; British Columbia south to California, east to the Atlantic Coast.
Habitat: Lake and pond shores, marshes, and wet forests.
Origin: Native
Flowers: June-September
Persicaria wallichiigarden knotweed, Himalayan knotweed
Distribution: Occurring west of the Cascades crest in Washington; British Columbia south to California; also in eastern North America.
Habitat: Waste areas, roadsides, and other disturbed areas where often where somewhat moist.
Origin: Introduced from eastern Asia
Flowers: July-October