Ceanothus sonomensis

Sonoma ceanothus

Family: Rhamnaceae · Type: shrub · Native

Conservation status: CNPS 1B.2

Sonoma ceanothus is a rare (CNPS 1B.2) California native shrub found in the northern Coast Ranges in the Hood Mountain region of Sonoma and Napa counties, growing on serpentine or volcanic substrates in chaparral at elevations of 140 to 600 meters. Flowering from March to April, this plant produces blue or lavender flowers in compact umbel-like clusters about 1 centimeter wide. Growing as an erect and somewhat open shrub less than 1.5 meters tall, it has ascending stems ranging from gray to brown with distinctive twigs. Its evergreen leaves are small and obovate, approximately 5 to 11 millimeters long, with a shiny green upper surface and gray, minutely tomentose underside, featuring 3 to 5 small spine-like teeth at the notched tip. The fruit is approximately 4 to 5 millimeters wide with two to three millimeter slender horns.

Habitat: Serpentine or volcanic substrates, chaparral

Bloom period: Mar-Apr

Elevation: 140-600 m

Bioregions: NCoRO (Hood Mtn region, Sonoma and Napa cos.).

California counties: Sonoma, Napa

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