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Taxon  Report  
Fallopia japonica  (Houtt.) Ronse Decr.
Japanese knotweed
Fallopia japonica is a perennial herb that is not native to California.
Cal-IPC rating: moderate
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Observation Search
(508 records)
redone or more occurrences
within a 7.5-minute quadrangle
bloom graphic
Bloom Period
Genus: Fallopia
Family: Polygonaceae  
Category: angiosperm  
PLANTS group:Dicot
Jepson eFlora section: eudicot

Wetlands: Occurs usually in non wetlands, occasionally in wetlands
Name Status:
Accepted by JEF
Alternate Names:
JEFPolygonum cuspidatum
JEFReynoutria japonica
JEFTiniaria japonica
PLANTSPolygonum cuspidatum
Information about  Fallopia japonica from other sources

USFS Fire Effects Information System: Three Asian Knotweeds

The Spruce landscaping journal: Overview of Control Methods.

USDA Species Profile: Japanese Knotweed Resources

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]. 2023. Berkeley, California: The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 01/30/2023).