Taxon  Report   10891 
Fallopia japonica  (Houtt.) Ronse Decr.
Japanese knotweed
Fallopia japonica
© 2006 Dr. Amadej Trnkoczy
More photos from
CalPhotos / Calflora
Fallopia japonica
© 2005 Louis-M. Landry
Fallopia japonica
© 2011 Louis-M. Landry
Fallopia japonica, a dicot, is a perennial herb that is not native to California. Cal-IPC rating: Moderate

Interactive Distribution Map

Observation Hotline
(observation details + photos)

point, line, or polygon

one or more occurrences
within a 7.5-minute quadrangle

Plant Characteristics
and Associations

Bloom Period
Fallopia japonica
© 2018 Rachel Kesel
Genus: Fallopia
escaped cultivar
Wetlands: Occurs usually in non wetlands, occasionally in wetlands
Name Status:
Accepted by JEF
PLANTS accepted name: Polygonum cuspidatum
Alternate Names:
(according to)

ICPN: Polygonum cuspidatum
ICPN: Reynoutria japonica
ICPN: Fallopia japonica var. japonica
More information about  Fallopia japonica
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]. 2018. Berkeley, California: The Calflora Database [a non-profit organization].
Available:   (Accessed: Sep 23, 2018).

The information on this page comes from diverse sources. None of the links are sponsored.