Reynoutria japonica Houttuyn var. japonica

Locations ofReynoutria japonica Houttuyn var. japonica in Virginia

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Botanical Name
Reynoutria japonica Houttuyn var. japonica
Common Name
Japanese Knotweed
Polygonum cuspidatum Siebold & Zucc.; Fallopia japonica (Houtt.) Ronse Decraene
Flora of Virginia Name/Status
Reynoutria japonica Houttuyn
This species can be terribly invasive on streamsides and other open alluvial situations. The hybrid with R. sachalinense may be found sparingly. It is reported (as Fallopia × bohemica) from Arlington Co. in Rhodora 105:150 (2003). According to Desjardins et al. (2023, PhytoKeys 220: 83-108), only var. japonica is in North America; three additional vars. (recognized under Fallopia in FNA) are endemic to Asia.
Roadsides, stream banks, sand or gravel bars, and other open, disturbed habitats, often forming dense thickets. Infrequent to locally common throughout.
Native Status

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