Alnus rhombifolia

White alder

Family: Betulaceae · Type: tree · Native

White alder is a California native tree found in the California Floristic Province and marginally in the Mojave Desert, growing along permanent streams at elevations of 100 to 2,400 meters. Flowering from January to April, this tree produces small, inconspicuous flowers typical of its species. Growing to heights of 35 meters with a broad, spreading form, it develops a sturdy trunk and branching structure. Its thick leaves are distinctive, with rounded to tapered bases, green on the upper surface and yellow-green underneath, featuring margins that are nearly flat and a prominent midrib. In riparian environments, white alder plays a crucial role in stabilizing stream banks and providing habitat for local wildlife.

Habitat: Along permanent streams

Bloom period: Jan-Apr

Elevation: 100-2400 m

Bioregions: CA-FP, MP (uncommon), w DSon

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

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