Taxon  Report   11015    
Persicaria wallichii  Greuter & Burdet
Himalayan knotweed
Persicaria wallichii
© 2001 CDFA
Photos from
CalPhotos / Calflora
Persicaria wallichii
© 2015 Phil Pullen
Persicaria wallichii
© 2001 CDFA
Persicaria wallichii, a dicot, is a perennial herb that is not native to California; it was introduced from elsewhere and naturalized in the wild. There is a high risk of this plant becoming invasive in California according to Cal-IPC.

Interactive Distribution Map

Observation Hotline
(observation details)

point, line, or polygon

one or more occurrences
within a 7.5-minute quadrangle

Plant Characteristics
and Associations

Bloom Period
Persicaria wallichii
© 2015 Phil Pullen
Genus: Persicaria
Communities: weed, characteristic of disturbed places, wetland-riparian

Wetlands: Equally likely to occur in wetlands and non wetlands

Habitat: disturbed

Name Status:
Accepted by JEF

PLANTS accepted name:
Polygonum polystachyum

Alternate Names:
ICPN: Polygonum polystachyum
ICPN: Persicaria wallichii var. wallichii
More information about  Persicaria wallichii
Photos on Google Images
Jepson eFlora

Records from the Consortium of California Herbaria

Search (Flora of North America)

website references from Google

Suggested Citation
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals, including the Consortium of California Herbaria. [web application]. 2019. Berkeley, California: The Calflora Database [a non-profit organization]. Available:   (Accessed: Jan 22, 2019).