Calflora, a 501c3 non-profit
Distribution by County   6746    
Polygonum cuspidatum  Siebold & Zucc.

(not an active name)
Japanese knotweed
Polygonum cuspidatum is a perennial herb that is not native to California.
also called Fallopia japonica
Cal-IPC rating: moderate
Record Count by County

Alameda: 7 Los Angeles: 1 San Francisco: 9 Siskiyou: 2
Butte: 3 Marin: 374 San Luis Obispo: 1 Sonoma: 12
Contra Costa: 1 Mendocino: 3 Santa Clara: 3
Del Norte: 17 Nevada: 1 Santa Cruz: 13
Humboldt: 55 Plumas: 1 Shasta: 2

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]. 2024. Berkeley, California: The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 12/03/2024).