Page author: David Giblin
Fallopia japonica
itadori knotweed
Specimens
Photos
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.
Flowers: June-September
Origin: Introduced from eastern Asia
Growth Duration: Perennial
Conservation Status: Not of concern
Pollination: Bees, flies, wasps
Description:
[none provided]
Accepted Name:
Fallopia japonica (Houtt.) Ronse Decr.
Publication: Bot. J. Linn. Soc. 98: 369. 1988.
Publication: Bot. J. Linn. Soc. 98: 369. 1988.
Synonyms & Misapplications:
Polygonum cuspidatum Siebold & Zucc. [HC]
Polygonum cuspidatum Siebold & Zucc. var. compactum (Hook. f.) L.H. Bailey
Reynoutria japonica Houtt.
Polygonum cuspidatum Siebold & Zucc. var. compactum (Hook. f.) L.H. Bailey
Reynoutria japonica Houtt.
Infraspecies:
-
var. japonica – Japanese knotweed
Occurring chiefly west of the Cascades crest in Washington; Alaska to California, east across North America to the Atlantic Coast.
Additional Resources:
PNW Herbaria: Specimen records of Fallopia japonica in the Consortium of Pacific Northwest Herbaria database
WA Flora Checklist: Fallopia japonica checklist entry
OregonFlora: Fallopia japonica information
E-Flora BC: Fallopia japonica atlas page
CalPhotos: Fallopia japonica photos
13 photographs:
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