Reynoutria sachalinensis (F. Schmidt ) Ronse Decraene
giant knotweed
Polygonaceae (Buckwheat family)

Introduction to Vascular Plants


© Adolf Ceska     (Photo ID #20526)


E-Flora BC Static Map

Distribution of Reynoutria sachalinensis
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Species Information

Perennial herb from a rhizome; stems erect, numerous, branched, 2-4 m tall, reddish, hollow.
Basal leaves lacking; stem leaves alternate, 10-30 cm long, the blades widely egg-shaped, the bases heart-shaped, the tips gradually tapered, long stalked; stipules tubular, entire.
Flowers in small axillary panicles; perianths 2-3 mm long, pale green or greenish-white, unequally 5-lobed, the outer lobes strongly winged.
Achenes, 3-angled, about 3 mm long, black, smooth and shiny.

SourceThe Illustrated Flora of British Columbia


If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.

Habitat and Range

Mesic fields, roadsides and waste places in the lowland zone; infrequent on Vancouver Island, the Gulf Islands and the Vancouver area, rare on the midcoast (Prince Rupert); introduced from Asia.

SourceThe Illustrated Flora of British Columbia


Synonyms and Alternate Names:
Fallopia sachalinensis