Calflora
Taxon  Report   10891    
Fallopia japonica  (Houtt.) Ronse Decr.
Japanese knotweed
Fallopia japonica, a dicot, is a perennial herb that is not native to California.
Cal-IPC rating: Moderate
Siskiyou Del Norte Modoc Humboldt Shasta Lassen Trinity Plumas Tehama Butte Mendocino Glenn Sierra Yuba Lake Nevada Colusa Placer Sutter El Dorado Yolo Alpine Napa Sonoma Sacramento Mono Amador Solano Calaveras Tuolumne San Joaquin Marin Contra Costa Alameda Santa Cruz Mariposa Madera San Francisco San Mateo Merced Fresno Stanislaus Santa Clara Inyo San Benito Tulare Kings Monterey San Bernardino San Luis Obispo Kern Santa Barbara Ventura Los Angeles Riverside Orange San Diego Imperial
Observation Search
(447 records)
one or more occurrences
within a 7.5-minute quadrangle

Bloom Period
Family: Polygonaceae  
Genus: Fallopia

Wetlands: Occurs usually in non wetlands, occasionally in wetlands
Name Status:
Accepted by ICPN
Alternate Names:
ICPNFallopia japonica var. japonica
ICPNPolygonum cuspidatum
More information about  Fallopia japonica
International Plants Names Index

Search efloras.org (Flora of North America)

Landscape information from Calscape

Photos on PlantID.net   /   Google Images

Consortium of California Herbaria 2

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]. 2021. Berkeley, California: The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 04/19/2021).