Calflora, a 501c3 non-profit
Distribution by County   6737    
Polygonum arenastrum  Boreau

(not an active name)
Common knotweed,   Dooryard knotweed,   Oval leaf knotweed
Polygonum arenastrum is an annual or perennial herb that is not native to California.
also called Polygonum aviculare ssp. depressum
Record Count by County

Alameda: 30 Lassen: 2 Riverside: 43 Solano: 13
Alpine: 6 Los Angeles: 71 Sacramento: 22 Sonoma: 31
Amador: 1 Marin: 39 San Benito: 10 Stanislaus: 7
Butte: 20 Mariposa: 21 San Bernardino: 28 Sutter: 5
Colusa: 1 Mendocino: 22 San Diego: 115 Tehama: 7
Contra Costa: 28 Merced: 12 San Francisco: 33 Trinity: 1
El Dorado: 11 Modoc: 19 San Joaquin: 5 Tulare: 23
Fresno: 20 Mono: 27 San Luis Obispo: 22 Tuolumne: 3
Glenn: 1 Monterey: 69 San Mateo: 45 Ventura: 35
Humboldt: 7 Napa: 7 Santa Barbara: 62 Yolo: 11
Imperial: 1 Nevada: 14 Santa Clara: 17 Yuba: 3
Inyo: 11 Orange: 13 Santa Cruz: 14
Kern: 15 Placer: 4 Shasta: 8
Lake: 5 Plumas: 17 Sierra: 8

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: 12/04/2024).