Polygonaceae
Buckwheat Family
12 genera
73 species
46 subspecies and varieties
73 species
46 subspecies and varieties
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Index to genera:
Aconogonon, Bistorta, Chorizanthe, Eriogonum, Fagopyrum, Fallopia, Oxyria, Oxytheca, Persicaria, Polygonum, Rheum, RumexAconogonon davisiae – Newberry's fleeceflower, Davis' knotweed, Davis's knotweed
Distribution: Occurring on both sides of the Cascades crest in Washington; Washington to California.
Habitat: Slopes and ridges in the subalpine and alpine.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades crest in Washington; Washington to California.
Habitat: Slopes and ridges in the subalpine and alpine.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Aconogonon phytolaccifolium – alpine fleeceflower
Distribution: Occurring chiefly east of the Cascades crest in Washington; Washington to California, east to Idaho, Montana, and Nevada.
Habitat: Subalpine to alpine ridges, meadows and talus slopes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Distribution: Occurring chiefly east of the Cascades crest in Washington; Washington to California, east to Idaho, Montana, and Nevada.
Habitat: Subalpine to alpine ridges, meadows and talus slopes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. phytolaccifolium – poke knotweed
Bistorta bistortoides – American bistort, western bistort
Distribution: Occurring on both sides of the Cascades in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Streambanks and moist or swampy meadows, middle elevations in the mountains to alpine slopes.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Streambanks and moist or swampy meadows, middle elevations in the mountains to alpine slopes.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Bistorta vivipara – alpine bistort, serpent-grass
Distribution: Occurring on both sides of the Cascades crest in northern Washington; Alaska to Oregon and Nevada, east to the Rocky Mountains, northern Great Plains, Great Lakes region, and northeastern North America.
Habitat: Damp areas, shady woods, meadows and streambanks at mid- to high elevations in the mountains.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades crest in northern Washington; Alaska to Oregon and Nevada, east to the Rocky Mountains, northern Great Plains, Great Lakes region, and northeastern North America.
Habitat: Damp areas, shady woods, meadows and streambanks at mid- to high elevations in the mountains.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Chorizanthe watsonii – five-tooth spineflower, Watson's spineflower
Distribution: Occurring east of the Cascades crest in central Washington; Washington to California, east to Montana, Utah, or Arizona.
Habitat: Sandy to gravelly flats and slopes, mixed grassland, saltbush and sagebrush communities, often where disturbed.
Origin: Native
Flowers: May-July
Growth Duration: Annual
Distribution: Occurring east of the Cascades crest in central Washington; Washington to California, east to Montana, Utah, or Arizona.
Habitat: Sandy to gravelly flats and slopes, mixed grassland, saltbush and sagebrush communities, often where disturbed.
Origin: Native
Flowers: May-July
Growth Duration: Annual
Eriogonum baileyi – Bailey's buckwheat
Distribution: Occurring east of the Cascades crest in the central region of Washington; northern Washington to California, east to Idaho and Utah.
Habitat: Sand or gravel flats and slopes, grassland and shrub-steppe, open forest, and washes.
Origin: Native
Flowers: April-June (September-October)
Growth Duration: Annual
Distribution: Occurring east of the Cascades crest in the central region of Washington; northern Washington to California, east to Idaho and Utah.
Habitat: Sand or gravel flats and slopes, grassland and shrub-steppe, open forest, and washes.
Origin: Native
Flowers: April-June (September-October)
Growth Duration: Annual
• var. baileyi – Bailey's buckwheat
Eriogonum cernuum – nodding buckwheat
Distribution: Occurring only in Franklin County, where disjunct from primary range of species; Washington to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Sand, gravel or clay slopes and flats, shrub-steppe, and grasslands.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Distribution: Occurring only in Franklin County, where disjunct from primary range of species; Washington to California, east to the Rocky Mountains and northern Great Plains.
Habitat: Sand, gravel or clay slopes and flats, shrub-steppe, and grasslands.
Origin: Native
Flowers: May-June
Growth Duration: Perennial
Eriogonum codium – basalt desert buckwheat, Umtanum buckwheat
Distribution: Occurring east of the Cascades crest in Washington, where endemic to Benton County.
Habitat: Volcanic soils in sagebrush along the Columbia River.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Distribution: Occurring east of the Cascades crest in Washington, where endemic to Benton County.
Habitat: Volcanic soils in sagebrush along the Columbia River.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Eriogonum compositum – arrow-leaf buckwheat, northern buckwheat
Distribution: Occurring chiefly east of the Cascades crest in Washington; Washington to California, east to Idaho.
Habitat: Dry, open areas, rocky slopes and cliffs from low elevations nearly to the subalpine.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Distribution: Occurring chiefly east of the Cascades crest in Washington; Washington to California, east to Idaho.
Habitat: Dry, open areas, rocky slopes and cliffs from low elevations nearly to the subalpine.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• var. compositum – northern buckwheat
• var. lancifolium – wild buckwheat
• var. leianthum – smooth arrow-leaf wild buckwheat
Eriogonum douglasii – Douglas's buckwheat
Distribution: Occurring east of the Cascades crest in Washington, chiefly in the central region; Washington to California, east to Idaho and Nevada.
Habitat: Sagebrush or juniper flats to ponderosa pine forests, often on lithosol.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Distribution: Occurring east of the Cascades crest in Washington, chiefly in the central region; Washington to California, east to Idaho and Nevada.
Habitat: Sagebrush or juniper flats to ponderosa pine forests, often on lithosol.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• var. douglasii – Douglas' buckwheat
Eriogonum elatum – rush buckwheat, tall buckwheat
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to southern Idaho and Nevada.
Habitat: Sand and gravel slopes and flats, grasslands, sagebrush desert, ponderosa pine forest openings, and montane ridges.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to southern Idaho and Nevada.
Habitat: Sand and gravel slopes and flats, grasslands, sagebrush desert, ponderosa pine forest openings, and montane ridges.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. elatum – tall buckwheat
Eriogonum flavum – yellow buckwheat
Distribution: Occurring east of the Cascades crest in southeastern Washington; Alaska to northeastern Oregon, east to the northern Great Plains.
Habitat: Open knolls in grasslands to alpine ridges and scree.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Distribution: Occurring east of the Cascades crest in southeastern Washington; Alaska to northeastern Oregon, east to the northern Great Plains.
Habitat: Open knolls in grasslands to alpine ridges and scree.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. piperi – Piper's buckwheat, yellow buckwheat
Eriogonum heracleoides – bractless parsnip-flowered wild buckwheat, parsnip-flowered buckwheat, parsnip-flowered eriogonum
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Montana, Wyoming and Colorado.
Habitat: Deeper soil of shrub-steppe to ponderosa pine forests and rocky ridges at middle elevation in the mountains.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Montana, Wyoming and Colorado.
Habitat: Deeper soil of shrub-steppe to ponderosa pine forests and rocky ridges at middle elevation in the mountains.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Eriogonum maculatum – spotted buckwheat
Distribution: Collected once (1884) in Yakima County in Washington and now considered extirpated; southeastern Oregon to southwestern Idaho, south to Baja California, Mexioca and east to New Mexico.
Habitat: Sand, gravel or clay slopes and flats, grassland, and shrub-steppe.
Origin: Native
Flowers: May-June
Growth Duration: Annual
Distribution: Collected once (1884) in Yakima County in Washington and now considered extirpated; southeastern Oregon to southwestern Idaho, south to Baja California, Mexioca and east to New Mexico.
Habitat: Sand, gravel or clay slopes and flats, grassland, and shrub-steppe.
Origin: Native
Flowers: May-June
Growth Duration: Annual
Eriogonum marifolium – marum-leaf wild buckwheat, mountain buckwheat
Distribution: Reported from east of the Cascades crest in Washington, but no specimens seen; central Washington to California, east to northwestern Nevada.
Habitat: Gravelly flats in lodgepole and ponderosa pine forests to alpine ridges and talus slopes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Distribution: Reported from east of the Cascades crest in Washington, but no specimens seen; central Washington to California, east to northwestern Nevada.
Habitat: Gravelly flats in lodgepole and ponderosa pine forests to alpine ridges and talus slopes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. marifolium – marum-leaf wild buckwheat, mountain buckwheat
Eriogonum microtheca – slender buckwheat
Distribution: Occurring east of the Cascades crest in central Washington; central Washington to California, east to the Rocky Mountains.
Habitat: Sandy deserts to lower mountain slopes, chiefly with sagebrush.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Distribution: Occurring east of the Cascades crest in central Washington; central Washington to California, east to the Rocky Mountains.
Habitat: Sandy deserts to lower mountain slopes, chiefly with sagebrush.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. laxiflorum – Great Basin slender buckwheat, Great Basin wild buckwheat
Eriogonum niveum – snow buckwheat
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to Oregon, east to Idaho.
Habitat: Sagebrush desert, dry ponderosa pine forest openings, in deep or sandy soil.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to Oregon, east to Idaho.
Habitat: Sagebrush desert, dry ponderosa pine forest openings, in deep or sandy soil.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Eriogonum nudum – bare-stem buckwheat, naked buckwheat
Distribution: Occurring on both sides of the Cascades crest in southern Washington; southern Washington to California and Nevada.
Habitat: Sandy or rocky places from the lowlands to subalpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades crest in southern Washington; southern Washington to California and Nevada.
Habitat: Sandy or rocky places from the lowlands to subalpine.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. nudum – barestem buckwheat, naked buckwheat
Eriogonum ovalifolium – cushion buckwheat, oval-leaved eriogonum
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Sagebrush deserts, juniper and ponderosa pine forests, to alpine ridges.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Sagebrush deserts, juniper and ponderosa pine forests, to alpine ridges.
Origin: Native
Flowers: May-August
Growth Duration: Perennial
• var. nivale – Sierra cushion buckwheat
• var. ovalifolium – cushion wild buckwheat
• var. purpureum – purple cushion wild buckwheat
Eriogonum pyrolifolium – alpine buckwheat, oarleaf buckwheat, Shasta wild buckwheat
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to Idaho and Montana.
Habitat: Open, often rocky areas, from middle elevations to the alpine in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to Idaho and Montana.
Habitat: Open, often rocky areas, from middle elevations to the alpine in the mountains.
Origin: Native
Flowers: July-September
Growth Duration: Perennial
Eriogonum sphaerocephalum – rock buckwheat, round-headed eriogonum
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to Idaho and Nevada.
Habitat: Sagebrush or juniper flats to ponderosa pine forests at low elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to Idaho and Nevada.
Habitat: Sagebrush or juniper flats to ponderosa pine forests at low elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• var. halimioides – rock buckwheat
• var. sphaerocephalum – rock buckwheat
• var. sublineare – scabland wild buckwheat
Eriogonum strictum – strict buckwheat
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to Montana, Idaho, and Nevada.
Habitat: Sandy or rocky soils, sagebrush desert to ponderosa pine forests.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to Montana, Idaho, and Nevada.
Habitat: Sandy or rocky soils, sagebrush desert to ponderosa pine forests.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• var. anserinum – Goose Lake wild buckwheat
• var. proliferum – strict buckwheat
• var. strictum – strict buckwheat
Eriogonum thymoides – thyme buckwheat, thyme-leaf wild buckwheat
Distribution: Occurring east of the Cascades crest in central Washington; central Washington to Oregon, east to Idaho.
Habitat: Sagebrush deserts, dry ponderosa pine forest openings, and open ridges in lower mountains.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Distribution: Occurring east of the Cascades crest in central Washington; central Washington to Oregon, east to Idaho.
Habitat: Sagebrush deserts, dry ponderosa pine forest openings, and open ridges in lower mountains.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Eriogonum umbellatum – sulfur buckwheat, sulfurflower
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Sagebrush deserts to alpine rocky ridges.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Sagebrush deserts to alpine rocky ridges.
Origin: Native
Flowers: June-September
Growth Duration: Perennial
• var. devestivum – emperor's sulfur flower
• var. ellipticum – starry sulfur flower
• var. haussknechtii – Haussknecht's sulfur flower
• var. hypoleium – Kittitas sulfur flower
• var. majus – subalpine sulfur flower
• var. sandbergii – Sandberg's sulfur flower
Eriogonum vimineum – broom buckwheat
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to Idaho and Nevada.
Habitat: Sagebrush deserts and dry ponderosa pine forest openings; tolerant of dry, disturbed conditions.
Origin: Native
Flowers: June-September
Growth Duration: Annual
Distribution: Occurring east of the Cascades crest in Washington; Washington to California, east to Idaho and Nevada.
Habitat: Sagebrush deserts and dry ponderosa pine forest openings; tolerant of dry, disturbed conditions.
Origin: Native
Flowers: June-September
Growth Duration: Annual
Fagopyrum esculentum – garden buckwheat
Distribution: Occurring chiefly east of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast.
Habitat: Roadsides, fields, waste areas; frequently escapes cultivation.
Origin: Introduced from Europe
Flowers: June-September
Growth Duration: Annual
Distribution: Occurring chiefly east of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast.
Habitat: Roadsides, fields, waste areas; frequently escapes cultivation.
Origin: Introduced from Europe
Flowers: June-September
Growth Duration: Annual
Fallopia baldschuanica – Bukhara fleeceflower, Chinese fleecevine, mile-a-minute vine
Distribution: Occurring chiefly west of the Cascades crest in Washington; southern British Columbia to Oregon, east to Idaho, also in scattered locations across North America.
Habitat: Roadsides, ditches, embankments, forest edge, and other disturbed open areas.
Origin: Introduced from central Asia
Flowers: Aug.-Sept.
Growth Duration: Perennial
Distribution: Occurring chiefly west of the Cascades crest in Washington; southern British Columbia to Oregon, east to Idaho, also in scattered locations across North America.
Habitat: Roadsides, ditches, embankments, forest edge, and other disturbed open areas.
Origin: Introduced from central Asia
Flowers: Aug.-Sept.
Growth Duration: Perennial
Fallopia ×bohemica – hybrid knotweed
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to Oregon, east to Montana, and in scattered locations across North America.
Habitat: Riparian zones, roadsides, ditches, wastelots, and other disturbed open areas generally at low elevations.
Origin: Introduced from eastern Asia
Flowers: July-October
Growth Duration: Perennial
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to Oregon, east to Montana, and in scattered locations across North America.
Habitat: Riparian zones, roadsides, ditches, wastelots, and other disturbed open areas generally at low elevations.
Origin: Introduced from eastern Asia
Flowers: July-October
Growth Duration: Perennial
Fallopia convolvulus – black bindweed, climbing bindweed, ivy bindweed
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Roadsides, ditches, wastelots, cultivated fields, and other disturbed open areas.
Origin: Introduced from Europe
Flowers: May-October
Growth Duration: Annual
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Roadsides, ditches, wastelots, cultivated fields, and other disturbed open areas.
Origin: Introduced from Europe
Flowers: May-October
Growth Duration: Annual
Fallopia japonica – itadori knotweed
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Riparian zones, roadsides, ditches, wastelots, and other disturbed open areas.
Origin: Introduced from eastern Asia
Flowers: June-September
Growth Duration: Perennial
Distribution: Occurring chiefly west of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Riparian zones, roadsides, ditches, wastelots, and other disturbed open areas.
Origin: Introduced from eastern Asia
Flowers: June-September
Growth Duration: Perennial
• var. japonica – Japanese knotweed
Fallopia sachalinensis – giant knotweed
Distribution: Occurring chiefly west of the Cascades crest and east in the Columbia River Gorge in Washington; Alaska to California, east to Idaho and Montana, also in eastern North America.
Habitat: Riparian zones, roadsides, meadows, ditches, and other disturbed areas generally at low elevations.
Origin: Introduced from eastern Asia
Flowers: July-September
Growth Duration: Perennial
Distribution: Occurring chiefly west of the Cascades crest and east in the Columbia River Gorge in Washington; Alaska to California, east to Idaho and Montana, also in eastern North America.
Habitat: Riparian zones, roadsides, meadows, ditches, and other disturbed areas generally at low elevations.
Origin: Introduced from eastern Asia
Flowers: July-September
Growth Duration: Perennial
Oxyria digyna – mountain-sorrel
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains; also east across Canada to Labrador.
Habitat: Moist, usually rocky ground, subalpine to alpine areas.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains; also east across Canada to Labrador.
Habitat: Moist, usually rocky ground, subalpine to alpine areas.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Oxytheca dendroidea – treelike puncture-bract
Distribution: Occurring east of the Cascades crest in Washington; central Washington to California, east to southern Idaho, Wyoming, and Nevada; also in South America.
Habitat: Sandy areas in sagebrush desert.
Origin: Native
Flowers: June-August
Growth Duration: Annual
Distribution: Occurring east of the Cascades crest in Washington; central Washington to California, east to southern Idaho, Wyoming, and Nevada; also in South America.
Habitat: Sandy areas in sagebrush desert.
Origin: Native
Flowers: June-August
Growth Duration: Annual
• ssp. dendroidea – treeline puncturebract
Persicaria amphibia – water 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
Growth Duration: Perennial
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
Growth Duration: Perennial
Persicaria hydropiper – smartweed, mild water-pepper
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast.
Habitat: Shores, swales, ditches, and disturbed ground.
Origin: Introduced from Europe
Flowers: July-September
Growth Duration: Annual
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across most of North America to the Atlantic Coast.
Habitat: Shores, swales, ditches, and disturbed ground.
Origin: Introduced from Europe
Flowers: July-September
Growth Duration: Annual
Persicaria hydropiperoides – water pepper, swamp smartweed
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia 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
Growth Duration: Perennial
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia 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
Growth Duration: Perennial
Persicaria lapathifolia – dock-leaf smartweed, pale smartweed, willow weed
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Streambanks, pond and lakeshores and other wet places.
Origin: Native
Flowers: May-September
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Streambanks, pond and lakeshores and other wet places.
Origin: Native
Flowers: May-September
Growth Duration: Perennial
Persicaria maculosa – heartweed, lady's-thumb, spotted lady's-thumb, redshank
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: A weedy species, usually on moist, cultivated or otherwise disturbed soil.
Origin: Introduced from Eurasia
Flowers: March-September
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: A weedy species, usually on moist, cultivated or otherwise disturbed soil.
Origin: Introduced from Eurasia
Flowers: March-September
Growth Duration: Perennial
Persicaria punctata – dotted knotweed, dotted smartweed, water smartweed
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to the Atlantic Coast.
Habitat: Lake and pond shores, marshes, and wet forests.
Origin: Native
Flowers: June-September
Growth Duration: Annual, Perennial
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to the Atlantic Coast.
Habitat: Lake and pond shores, marshes, and wet forests.
Origin: Native
Flowers: June-September
Growth Duration: Annual, Perennial
Persicaria wallichii – garden knotweed
Distribution: Occurring west of the Cascades crest in Washington; British Columbia 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
Growth Duration: Perennial
Distribution: Occurring west of the Cascades crest in Washington; British Columbia 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
Growth Duration: Perennial
• var. wallichii – garden knotweed, Himalayan knotweed
Polygonum achoreum – Blake's knotweed
Distribution: Reported for Washington, but specimen from Pierce County is likely a misidentification; Alaska to Oregon and Nevada, east across North America to the Atlantic Coast.
Habitat: Disturbed areas.
Origin: Native
Flowers: May-July
Growth Duration: Annual
Distribution: Reported for Washington, but specimen from Pierce County is likely a misidentification; Alaska to Oregon and Nevada, east across North America to the Atlantic Coast.
Habitat: Disturbed areas.
Origin: Native
Flowers: May-July
Growth Duration: Annual
Polygonum austiniae – Austin's knotweed
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Alberta and Wyoming.
Habitat: Dry to moist banks and flats, from sagebrush plains to lower mountains, often with ponderosa pine.
Origin: Native
Flowers: June-August
Growth Duration: Annual
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Alberta and Wyoming.
Habitat: Dry to moist banks and flats, from sagebrush plains to lower mountains, often with ponderosa pine.
Origin: Native
Flowers: June-August
Growth Duration: Annual
Polygonum aviculare – common knotweed
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Dry or slightly moist, disturbed soil, often where hard-packed.
Origin: Both native and introduced
Flowers: May-October
Growth Duration: Annual
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Dry or slightly moist, disturbed soil, often where hard-packed.
Origin: Both native and introduced
Flowers: May-October
Growth Duration: Annual
• ssp. aviculare – common knotweed, yard knotweed
• ssp. buxiforme – American knotweed, prairie knotweed
• ssp. depressum – common knotweed, oval-leaf knotweed
• ssp. neglectum – narrow-leaf knotweed
Polygonum californicum – California knotweed
Distribution: Occurring in the east end of the Columbia River Gorge in Washington; south-central Washington to California.
Habitat: Dry rocky slopes, gravelly ground at low elevations.
Origin: Native
Flowers: May-July
Growth Duration: Annual
Distribution: Occurring in the east end of the Columbia River Gorge in Washington; south-central Washington to California.
Habitat: Dry rocky slopes, gravelly ground at low elevations.
Origin: Native
Flowers: May-July
Growth Duration: Annual
Polygonum douglasii – Douglas' knotweed, Douglas's knotweed
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and across the northern U.S. and Canada to the Atlantic Coast.
Habitat: Common in dry to moist areas, lowlands to middle elevations in the mountains.
Origin: Native
Flowers: June-September
Growth Duration: Annual
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains and across the northern U.S. and Canada to the Atlantic Coast.
Habitat: Common in dry to moist areas, lowlands to middle elevations in the mountains.
Origin: Native
Flowers: June-September
Growth Duration: Annual
Polygonum erectum – erect knotweed
Distribution: Occurring on both sides of the Cascades crest in Washington; Washington to Oregon and Nevada, east from the Rocky Mountains and northern Great Plains to the Altantic Coast.
Habitat: Dry, disturbed ground.
Origin: Native
Flowers: June-September
Growth Duration: Annual
Distribution: Occurring on both sides of the Cascades crest in Washington; Washington to Oregon and Nevada, east from the Rocky Mountains and northern Great Plains to the Altantic Coast.
Habitat: Dry, disturbed ground.
Origin: Native
Flowers: June-September
Growth Duration: Annual
Polygonum fowleri – Fowler's knotweed
Distribution: Occurring west of the Cascades crest in Washington; Alaska to California, east across Canada to northeastern North America.
Habitat: Coastal salt marshes.
Origin: Native
Flowers: July-November
Growth Duration: Annual
Distribution: Occurring west of the Cascades crest in Washington; Alaska to California, east across Canada to northeastern North America.
Habitat: Coastal salt marshes.
Origin: Native
Flowers: July-November
Growth Duration: Annual
• ssp. fowleri – Fowler's knotweed
Polygonum majus – Palouse knotweed, wiry knotweed
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Dry, often semi-barren, gravelly to heavy soil, sagebrush desert to lower mountains.
Origin: Native
Flowers: May-August
Growth Duration: Annual
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Dry, often semi-barren, gravelly to heavy soil, sagebrush desert to lower mountains.
Origin: Native
Flowers: May-August
Growth Duration: Annual
Polygonum minimum – leafy dwarf knotweed, zigzag knotweed
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains.
Habitat: Open or semi-barren soil in the alpine and subalpine.
Origin: Native
Flowers: July-September
Growth Duration: Annual
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains.
Habitat: Open or semi-barren soil in the alpine and subalpine.
Origin: Native
Flowers: July-September
Growth Duration: Annual
Polygonum nuttallii – Nuttall's knotweed
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to Oregon, east to Idaho.
Habitat: Prairies, grassy balds, and forest openings at low to moderate elevations.
Origin: Native
Flowers: May-July
Growth Duration: Annual
Distribution: Occurring chiefly west of the Cascades crest in Washington; British Columbia to Oregon, east to Idaho.
Habitat: Prairies, grassy balds, and forest openings at low to moderate elevations.
Origin: Native
Flowers: May-July
Growth Duration: Annual
Polygonum paronychia – beach knotweed, black knotweed
Distribution: Occurring west of the Cascades crest along the coast; Vancouver Island, B.C., south to Monterey, California.
Habitat: Coastal shorelines and sand dunes.
Origin: Native
Flowers: April-September
Growth Duration: Perennial
Distribution: Occurring west of the Cascades crest along the coast; Vancouver Island, B.C., south to Monterey, California.
Habitat: Coastal shorelines and sand dunes.
Origin: Native
Flowers: April-September
Growth Duration: Perennial
Polygonum parryi – Parry's knotweed, prickly knotweed
Distribution: Occurring in the east end of the Columbia River Gorge in Washington; south-central Washington to California.
Habitat: Vernal pools, seasonally damp ground at low elevations.
Origin: Native
Flowers: June-July
Growth Duration: Annual
Distribution: Occurring in the east end of the Columbia River Gorge in Washington; south-central Washington to California.
Habitat: Vernal pools, seasonally damp ground at low elevations.
Origin: Native
Flowers: June-July
Growth Duration: Annual
Polygonum polygaloides – white-margined knotweed
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Meadows, vernal pools and rocky ridges, lowlands to mid-elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Annual
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Rocky Mountains.
Habitat: Meadows, vernal pools and rocky ridges, lowlands to mid-elevations in the mountains.
Origin: Native
Flowers: June-August
Growth Duration: Annual
• ssp. confertiflorum – close-flowered knotweed
• ssp. kelloggii – white-margin knotweed
• ssp. polygaloides – pokeweed fleeceflower, white-margined knotwee
Polygonum ramosissimum – branched knotweed
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Disturbed areas, often where wet, from low to middle elevations.
Origin: Native
Flowers: July-September
Growth Duration: Annual
Distribution: Occurring chiefly east of the Cascades crest in Washington; British Columbia to California, east across North America to the Atlantic Coast.
Habitat: Disturbed areas, often where wet, from low to middle elevations.
Origin: Native
Flowers: July-September
Growth Duration: Annual
• ssp. prolificum – proliferous knotweed
• ssp. ramosissimum – bushy knotweed
Polygonum sawatchense – Sawatch knotweed
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Great Plains.
Habitat: Dry to moist forest openings and meadows from moderate elevations to the subalpine.
Origin: Native
Flowers: June-August
Growth Duration: Annual
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to the Great Plains.
Habitat: Dry to moist forest openings and meadows from moderate elevations to the subalpine.
Origin: Native
Flowers: June-August
Growth Duration: Annual
• ssp. oblivium – sublime knotweed
• ssp. sawatchense – Sawatch knotweed
Polygonum spergulariiforme – fall knotweed, spurry knotweed
Distribution: Occurring west of the Cascades crest and east in the Columbia River Gorge in Washington; British Columbia to California, east to Idaho, Montana, and Wyoming.
Habitat: Balds, prairies, and headlands in gravelly, sandy or heavy, dry or moist soil at low elevations.
Origin: Native
Flowers: June-September
Growth Duration: Annual
Distribution: Occurring west of the Cascades crest and east in the Columbia River Gorge in Washington; British Columbia to California, east to Idaho, Montana, and Wyoming.
Habitat: Balds, prairies, and headlands in gravelly, sandy or heavy, dry or moist soil at low elevations.
Origin: Native
Flowers: June-September
Growth Duration: Annual
Rheum rhabarbarum – rhubarb
Distribution: Occurring in scattered locations on both sides of the Cascades crest; Alaska an Yukon Territory, Rocky Mountain states, and eastern North America.
Habitat: Open, disturbed areas, often associated with former homesteads.
Origin: Introduced
Flowers: May-June
Distribution: Occurring in scattered locations on both sides of the Cascades crest; Alaska an Yukon Territory, Rocky Mountain states, and eastern North America.
Habitat: Open, disturbed areas, often associated with former homesteads.
Origin: Introduced
Flowers: May-June
Rumex acetosa – alpine sorrel, common sorrel, garden sorrel, Lapland sorrel
Distribution: Occurring in scattered locations in Washington; Alaska to Oregon, east across Canada to the Great Lakes region and northeastern North America.
Habitat: Roadsides, wastelots, and other disturbed sites at low elevations.
Origin: Introduced from Eurasia
Flowers: April-July
Growth Duration: Perennial
Distribution: Occurring in scattered locations in Washington; Alaska to Oregon, east across Canada to the Great Lakes region and northeastern North America.
Habitat: Roadsides, wastelots, and other disturbed sites at low elevations.
Origin: Introduced from Eurasia
Flowers: April-July
Growth Duration: Perennial
Rumex acetosella – common sheep sorrel
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Balds, prairies, meadows, pastures, fields, roadsides, wastelots, lawns and other disturbed open areas from the lowlands to middle elevations in the mountains.
Origin: Introduced from Eurasia
Flowers: May-August
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Balds, prairies, meadows, pastures, fields, roadsides, wastelots, lawns and other disturbed open areas from the lowlands to middle elevations in the mountains.
Origin: Introduced from Eurasia
Flowers: May-August
Growth Duration: Perennial
Rumex conglomeratus – clustered dock, sharp dock
Distribution: Occurring west of the Cascades crest in Washington; British Columbia to California, east to Nevada and Arizona; also in eastern North America.
Habitat: A weed of waste ground.
Origin: Introduced from Eurasia
Flowers: June-September
Growth Duration: Perennial
Distribution: Occurring west of the Cascades crest in Washington; British Columbia to California, east to Nevada and Arizona; also in eastern North America.
Habitat: A weed of waste ground.
Origin: Introduced from Eurasia
Flowers: June-September
Growth Duration: Perennial
Rumex crassus – fleshy willow dock
Distribution: Occurring west of the Cascades crest along the outer coast in Washington; Washington to California.
Habitat: Coastal dunes, sandy shores, and marshes
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Distribution: Occurring west of the Cascades crest along the outer coast in Washington; Washington to California.
Habitat: Coastal dunes, sandy shores, and marshes
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Rumex crispus – curly dock, sour dock
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Meadows, fields, roadsides, wastelots, and other disturbed, open areas.
Origin: Introduced from Eurasia
Flowers: June-September
Growth Duration: Biennial, Perennial
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Habitat: Meadows, fields, roadsides, wastelots, and other disturbed, open areas.
Origin: Introduced from Eurasia
Flowers: June-September
Growth Duration: Biennial, Perennial
Rumex dentatus – toothed dock
Distribution: Occurring on both sides of the Cascades crest in Washington; Washington to California, east across North America in scattered locations to the Atlantic Coast.
Habitat: Ditches, shores, and ballast.
Origin: Introduced from Eurasia
Flowers: June-August
Growth Duration: Biennial, Perennial
Distribution: Occurring on both sides of the Cascades crest in Washington; Washington to California, east across North America in scattered locations to the Atlantic Coast.
Habitat: Ditches, shores, and ballast.
Origin: Introduced from Eurasia
Flowers: June-August
Growth Duration: Biennial, Perennial
Rumex maritimus – golden dock
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to eastern North America except for southeastern U.S.
Habitat: Shores, wetlands, and disturbed ground.
Origin: Native
Flowers: June-September
Growth Duration: Annual, Biennial
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to eastern North America except for southeastern U.S.
Habitat: Shores, wetlands, and disturbed ground.
Origin: Native
Flowers: June-September
Growth Duration: Annual, Biennial
• ssp. fueginus – American golden dock, Tierra del Fuego dock
Rumex obtusifolius – bitter dock
Distribution: Occurring on both sides of the Cascades in Washington; Alaska to California, east to the Atlantic Coast.
Habitat: Moist roadsides and wasteland.
Origin: Introduced from Euraisa
Flowers: March-September
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades in Washington; Alaska to California, east to the Atlantic Coast.
Habitat: Moist roadsides and wasteland.
Origin: Introduced from Euraisa
Flowers: March-September
Growth Duration: Perennial
Rumex occidentalis – western dock
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains, northern Great Plains, Great Lakes region, and eastern Canada.
Habitat: Moist to swampy areas and wet meadows, from the sea coast to foothill valleys.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Rocky Mountains, northern Great Plains, Great Lakes region, and eastern Canada.
Habitat: Moist to swampy areas and wet meadows, from the sea coast to foothill valleys.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
• var. occidentalis – western dock
Rumex patientia – patience dock
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to Oregon, east to the Atlantic Coast.
Habitat: Roadsides and other disturbed, open ground
Origin: Introduced from Eurasia
Flowers: May-August
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades crest in Washington; British Columbia to Oregon, east to the Atlantic Coast.
Habitat: Roadsides and other disturbed, open ground
Origin: Introduced from Eurasia
Flowers: May-August
Growth Duration: Perennial
Rumex paucifolius – alpine sheep sorrel, alpine sorrel, mountain sorrel
Distribution: Occurring east of the Cascades crest in Washington; southern British Columbia to California, east to the Rocky Mountains.
Habitat: Moist grasslands, stream banks, and montane to alpine meadows.
Origin: Native
Flowers: June -August
Growth Duration: Perennial
Distribution: Occurring east of the Cascades crest in Washington; southern British Columbia to California, east to the Rocky Mountains.
Habitat: Moist grasslands, stream banks, and montane to alpine meadows.
Origin: Native
Flowers: June -August
Growth Duration: Perennial
Rumex persicarioides – seashore dock, yellow dock
Distribution: Occurring west of the Cascades crest along the coast in Washington; British Columbia to California, also in eastern North America.
Habitat: Beaches, shores, and slightly saline marshes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Distribution: Occurring west of the Cascades crest along the coast in Washington; British Columbia to California, also in eastern North America.
Habitat: Beaches, shores, and slightly saline marshes.
Origin: Native
Flowers: June-August
Growth Duration: Perennial
Rumex salicifolius – willow dock
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Atlantic Coast
Habitat: Streambanks, moist meadows, beaches, alkaline shores, roadsides, and other open places from low to moderate elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
Distribution: Occurring on both sides of the Cascades crest in Washington; Alaska to California, east to the Atlantic Coast
Habitat: Streambanks, moist meadows, beaches, alkaline shores, roadsides, and other open places from low to moderate elevations.
Origin: Native
Flowers: May-July
Growth Duration: Perennial
• var. angustivalvis – western willow dock
• var. transitorius – narrow-leaved dock, Pacific willow dock
• var. triangulivalvis – triangular-valved dock, white willow dock
Rumex sanguineus – red-vein dock
Distribution: Occurring chiefly west of the Cascades crest in Washington; southwestern British Columbia to Oregon, also in eastern North America.
Habitat: sSream banks, disturbed ground, shores, and marshes.
Origin: Introduced from Eurasia
Flowers: June-September
Growth Duration: Perennial
Distribution: Occurring chiefly west of the Cascades crest in Washington; southwestern British Columbia to Oregon, also in eastern North America.
Habitat: sSream banks, disturbed ground, shores, and marshes.
Origin: Introduced from Eurasia
Flowers: June-September
Growth Duration: Perennial
Rumex stenophyllus – narrow-leaved dock, narrowleaf dock
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Alberta, Montana, and Wyoming, scattered eastward to the eastern U.S.
Habitat: Dune swales, marshes, shores, fens, and ditches.
Origin: Introduced from Eurasia
Flowers: May-July
Growth Duration: Perennial
Distribution: Occurring east of the Cascades crest in Washington; British Columbia to California, east to Alberta, Montana, and Wyoming, scattered eastward to the eastern U.S.
Habitat: Dune swales, marshes, shores, fens, and ditches.
Origin: Introduced from Eurasia
Flowers: May-July
Growth Duration: Perennial
Rumex venosus – veiny dock, winged dock
Distribution: Occurring east of the Cascades crest in Washington; Alberta to California, east to the Rocky Mountains and Great Plains.
Habitat: Sand dunes and sandy river banks to dry, gravelly soil, sagebrush deserts and grasslands at low elevations.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
Distribution: Occurring east of the Cascades crest in Washington; Alberta to California, east to the Rocky Mountains and Great Plains.
Habitat: Sand dunes and sandy river banks to dry, gravelly soil, sagebrush deserts and grasslands at low elevations.
Origin: Native
Flowers: April-June
Growth Duration: Perennial
