Calflora, a 501c3 non-profit
Distribution by County   6754    
Polygonum hydropiper  L.

(not an active name)
Common smartweed,   Marsh pepper,   Marshpepper knotweed
Polygonum hydropiper is an annual herb that is not native to California.
also called Persicaria hydropiper
Record Count by County

Alameda: 3 Inyo: 4 Placer: 2 Sonoma: 8
Amador: 2 Kern: 2 Plumas: 2 Stanislaus: 1
Butte: 33 Los Angeles: 1 Riverside: 1 Sutter: 1
Calaveras: 1 Madera: 5 Sacramento: 8 Tehama: 5
Contra Costa: 1 Mariposa: 5 San Joaquin: 6 Trinity: 2
El Dorado: 6 Mendocino: 4 Santa Clara: 4 Tuolumne: 2
Fresno: 2 Merced: 1 Shasta: 4 Yolo: 1
Glenn: 1 Napa: 3 Siskiyou: 2 Yuba: 3
Humboldt: 2 Nevada: 5 Solano: 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: 05/13/2024).