Toxicodendron diversilobum

Western poison oak

Family: Anacardiaceae · Type: shrub · Native

Western poison oak is a native shrub found in California Floristic Province and southwestern edge of the Mojave Desert in canyons, slopes, chaparral, coastal scrub, and oak woodland at elevations below 2,000 meters. Flowering from April to June, this plant produces yellow- to white-green flowers in loose, generally arched branches. Growing 0.5 to 4 meters tall, it can also develop as a vine-like plant with adventitious roots and gray- to red-brown twigs. Its distinctive leaves grow in clusters of three leaflets that turn bright red in autumn, with terminal leaflets 1 to 13 centimeters long, and are characteristically shiny and glabrous on the upper surface. The fruit is a spheric, creamy white berry 1.5 to 6 millimeters in diameter that develops a leathery texture with age.

Habitat: Canyons, slopes, chaparral, coastal scrub, oak woodland

Bloom period: Apr-Jun

Elevation: < 2000 m

Bioregions: CA-FP, sw edge DMoj

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

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