Calflora, a 501c3 non-profit
Distribution by County   2118    
Cirsium arvense  (L.) Scop.
Canada thistle
Cirsium arvense is a perennial herb that is not native to California.
Cal-IPC rating: moderate
Record Count by County

Alameda: 10 Kern: 1 Plumas: 1346 Siskiyou: 150
Alpine: 169 Lake: 10 Sacramento: 3 Solano: 5
Amador: 2 Lassen: 271 San Benito: 20 Sonoma: 15
Butte: 17 Los Angeles: 3 San Diego: 1 Stanislaus: 1
Calaveras: 1 Marin: 12 San Francisco: 6 Tehama: 10
Colusa: 1 Mendocino: 97 San Joaquin: 7 Trinity: 138
Contra Costa: 4 Merced: 1 San Luis Obispo: 3 Tulare: 1
Del Norte: 12 Modoc: 195 San Mateo: 6 Tuolumne: 6
El Dorado: 30 Mono: 41 Santa Barbara: 4 Ventura: 4
Fresno: 3 Monterey: 12 Santa Clara: 7 Yolo: 3
Glenn: 21 Nevada: 19 Santa Cruz: 9
Humboldt: 240 Orange: 2 Shasta: 27
Inyo: 32 Placer: 22 Sierra: 42

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: 11/23/2024).