Polygonum aviculare subsp. depressum

Family: Polygonaceae · Type: perennial · Not Native

Prostrate knotweed is a naturalized annual herb found in disturbed places throughout California at elevations below 2,000 meters. Flowering from May to November, this plant produces small greenish or red-brown flowers with white margins, clustered in dense groups of 2 to 7 blooms. Growing as a low, spreading mat with numerous branches, it forms prostrate stems 10 to 50 centimeters long that creep along the ground. Its leaves are elliptic to narrowly elliptic, 8 to 27 millimeters long and 2 to 7 millimeters wide, with obtuse or acute tips and a longitudinal striped texture. The dark brown fruit is slightly exserted, triangular, and typically 1.5 to 2.7 millimeters long with a striate-tubercled surface.

Habitat: Disturbed places

Bloom period: May-Nov

Elevation: < 2000 m

Bioregions: CA

California counties: Alpine, San Diego, Santa Barbara, Ventura, Los Angeles, Monterey, San Francisco, Kern, Inyo, San Bernardino, Marin, Alameda, Contra Costa, Fresno, Mendocino, Nevada, Stanislaus, Tehama, Trinity, Tuolumne, Butte, Lake, Mariposa, Plumas, San Luis Obispo, San Mateo, Santa Clara, Santa Cruz, Shasta, Siskiyou, Sonoma, Tulare, Yolo, El Dorado, Lassen, Humboldt, Napa, Mono, Riverside, Modoc, Solano, Placer, Imperial, Sacramento, Merced, Sierra, Amador, Yuba, Sutter, Madera, San Joaquin

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Jepson eFlora, Cal-IPC, and more.