Calflora
Taxon  Report   11010    
Persicaria lapathifolia  (L.) Delarbe
Common knotweed
Persicaria lapathifolia
© 2008 Louis-M. Landry
Photos from
CalPhotos / Calflora
Persicaria lapathifolia
© 2005 Luigi Rignanese
Persicaria lapathifolia
© 2013 Neal Kramer
Persicaria lapathifolia, a dicot, is an annual herb that is native to California, is also found elsewhere in North America and beyond.

Interactive Distribution Map


Observation Hotline
(observation details)



point, line, or polygon

Plant Characteristics
and Associations



Bloom Period
Persicaria lapathifolia
© 2016 Barbara Boethling
Family: POLYGONACEAE  
Genus: Persicaria
Communities: (many plant communities), wetland-riparian

Wetlands: Occurs usually in wetlands, occasionally in non wetlands

Name Status:
Accepted by JEF

PLANTS accepted name:
Polygonum lapathifolium

Alternate Names:
ICPN: Polygonum lapathifolium
More information about  Persicaria lapathifolia
Nursery / seed vendor availability from CNPLX
Commercial availability unknown.
Landscaping information from Calscape
Photos on PlantID.net   /   Google Images
Jepson eFlora

Records from the Consortium of California Herbaria

USDA PLANTS Profile (POLA4)

Search efloras.org (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: https://www.calflora.org/   (Accessed: Jan 17, 2019).