Page authors: Don Knoke, David Giblin
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.

Flowers: May-September

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Bees, flies


Somewhat pubescent annual with an erect, freely-branched stem 3-6 dm. tall.


Leaf blades on short petioles, lanceolate to elliptic-lanceolate, 6-15 cm. long and about 3.5 cm. broad, covered with short, appressed to somewhat woolly hairs; stipules brownish, truncate with straight hairs around the top, but not lacerate, the tube not bristly.


Inflorescence a loose panicle of several erect to pendant, many-flowered, spike-liked racemes, the branches glandular; perianth white or green to pink, the segments 4 or 5, the outer pair obovate, 2.5 mm. long, strongly 3-nerved.

Identification Notes:

Achene lenticular, 2-3 mm. long, ovate, dark brown, smooth and shining.

Accepted Name:
Persicaria lapathifolia (L.) Gray
Publication: Nat. Arr. Brit. Pl. 2: 270. 1821.

Synonyms & Misapplications:
Polygonum incanum F.W. Schmidt
Polygonum incarnatum Elliott
Polygonum lapathifolium L. [HC]
Polygonum lapathifolium L. var. salicifolium Sibth.
Polygonum linicola Sutulov
Polygonum nodosum Pers.
Polygonum scabrum Moench
Polygonum tomentosum Willd.
Additional Resources:

PNW Herbaria: Specimen records of Persicaria lapathifolia in the Consortium of Pacific Northwest Herbaria database

WA Flora Checklist: Persicaria lapathifolia checklist entry

OregonFlora: Persicaria lapathifolia information

E-Flora BC: Persicaria lapathifolia atlas page

CalPhotos: Persicaria lapathifolia photos

42 photographs:
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