Conium maculatum

Poison hemlock

Family: Apiaceae · Type: biennial · Not Native

Conservation status: Cal-IPC Yes

Poison hemlock is a naturalized biennial found in California Floristic Province and Great Basin regions in moist, disturbed places at elevations below 1,500 meters. Flowering from April to July, this plant produces small white flowers in delicate, many-branched clusters with 10 to 20 rays. Growing 50 to 300 centimeters tall with distinctively purple-spotted or purple-streaked stems, it develops a widely branching structure. Its complex leaves are two-pinnate, with broad triangular blades up to 30 centimeters long and dilated leaf stalks. The small oval fruits are approximately 2 to 3 millimeters wide with generally wavy ribs.

Habitat: Common. Moist, especially disturbed places

Bloom period: Apr-Jul

Elevation: < 1500 m

Bioregions: CA-FP, GB (uncommon)

California counties: Los Angeles, Tulare, Mendocino, Butte, San Luis Obispo, Orange, Santa Cruz, Kern, San Bernardino, Monterey, Alameda, San Diego, San Mateo, Sonoma, San Joaquin, Santa Barbara, Riverside, San Francisco, Tuolumne, Humboldt, Ventura, Marin, Mono, Modoc, Santa Clara, Contra Costa, Merced, Siskiyou, Placer, Sacramento, Sutter, Amador, Yolo, Solano, Glenn, Tehama, Lassen, Napa, Del Norte, Nevada, Trinity, Sierra, Colusa, Stanislaus, El Dorado

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