Taxon  Report   11010 
Persicaria lapathifolia  (L.) Gray
Common knotweed
Persicaria lapathifolia
© 2008 Louis-M. Landry
Click on a photo to see it bigger.
Persicaria lapathifolia
© 2009 Phil Pullen
Persicaria lapathifolia
© 2005 Luigi Rignanese
Persicaria lapathifolia, a dicot, is an annual herb that is native to California and is also found elsewhere in North America and beyond.

Interactive Distribution Map

Observation Hotline
(observation details + photos)

point, line, or polygon

Plant Characteristics
and Associations

Bloom Period
Persicaria lapathifolia
© 2008 Louis-M. Landry
Genus: Persicaria
(many plant communities), wetland-riparian
Wetlands:Occurs almost always under natural conditions in wetlands [U.S. Fish & Wildlife Service.]
Distribution by County 

Add an Observation of  Persicaria lapathifolia

Name Status:
Accepted by TJM2
Alternate Names:
(according to)

TJM2: Polygonum lapathifolium
More information about  Persicaria lapathifolia
Nursery / seed vendor availability from CNPLX
Commercial availability unknown.
Photos on CalPhotos / Google Images
Photos and ID tips from

Jepson eFlora

Records from the Consortium of California Herbaria


Search (Flora of North America)

Search the Lady Bird Johnson Wildflower Center

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]. 2016. Berkeley, California: The Calflora Database [a non-profit organization].
Available:   (Accessed: Oct 23, 2016).

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