E-Flora BC: Electronic Atlas of the Flora of British Columbia

Persicaria wallichii Greuter & Burdet
Himalayan knotweed
Polygonaceae (Buckwheat family)

Introduction to Vascular Plants

Distribution of Persicaria wallichii
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Species Information

General:
Perennial herb from strongly creeping rhizomes; stems erect, numerous, branched, 1-2 m tall, reddish-brown.

Leaves:
Basal leaves lacking; stem leaves alternate, lanceolate, the blades up to 20 cm long, densely soft- hairy, the base rounded to somehat heart-shaped, often with 2 small lobes, the stalks short; stipules sheathing, entire.

Flowers:
Inflorescence a wide, diffuse panicle; perianth segments white, 3-5 mm long, not keeled on the back.

Fruits:
Apparently sterile in our range.

Source: The Illustrated Flora of British Columbia

Habitat / Range

Mesic fields and waste places in the lowland zone; rare in extreme SW BC and the Queen Charlotte Islands; introduced from SC Asia.

Source: The Illustrated Flora of British Columbia

Additional Notes

Persicaria wallichii is considered an emerging invasive species in the Vancouver region by the Greater Vancouver Invasive Plant Council (2009). An emerging invasive is defined by them as: currently found in isolated, sparse populations but are rapidly expanding their range within the region.

Climate

The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Status Information

Origin Status	Provincial Status	BC List (Red Blue List)	COSEWIC
Unlisted	Unlisted	Unlisted	Unlisted

BC Ministry of Environment: BC Species and Ecosystems Explorer, the authoritative source for conservation information in British Columbia.

Synonyms and Alternate Names

Aconogonum polystachyum
Polygonum polystachyum Wall. ex Meisn.

Taxonomic and Nomenclatural Links

Flora North America treatment for Polygonaceae
Flora North America treatment for Persicaria wallichii
Genetic information (NCBI Taxonomy Database)
International Plant Names Index
Taxonomic Information from the World Flora Online
Integrated Taxonomic Information System

Additional Range and Status Information Links

Burke Museum of Natural History (Washington State records)
CalFlora
Consortium of Pacific Northwest Herbaria records
Jepson Interchange
NatureServe Explorer

Additional Photo Sources

Images From CalPhoto
UT Austin's Native Plant Database
Google Image Search
Flickr Image Search

General References

Google Scholar Search
Family References
General Botanical References for BC

Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2020. E-Flora BC: Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2024-05-09 8:44:45 PM ]

Disclaimer: The information contained in the E-Flora atlas pages is derived from expert sources as cited in each section. This information is scientifically based. E-Flora also acts as a portal to other sites via deep links. As always, users should refer to the original sources for complete information. E-Flora BC is not responsible for the accuracy or completeness of the original information.