Ceanothus cordulatus
Mountain whitethorn
(c) Steve Matson, some rights reserved (CC BY), uploaded by Steve Matson · licence
Family: Rhamnaceae · Type: Shrub · Native
Ceanothus cordulatus (Mountain whitethorn) is a native California shrub in the Rhamnaceae family, recognized by . Thorn-like twigs and 3-ribbed alternate leaves diagnostic.
Mountain whitethorn is a California native shrub found in the Klamath Ranges, northern Coast Ranges, high Cascade Range, northern Sierra Nevada Forests, Sierra Nevada, Transverse Ranges, San Jacinto Mountains, Modoc Plateau, and eastern desert mountains including the Panamint Range in open conifer forests and mountain slopes at elevations of 365 to 3,355 meters. Flowering from May to July, this plant produces white flowers in small raceme- or panicle-like clusters generally 1 to 4 centimeters long. Growing as an open shrub less than 1.5 meters tall with rigid, thorn-like pale gray to gray-green twigs that spread widely, it forms a distinctive branching structure. Its alternate evergreen leaves are ovate to elliptic, 9 to 25 millimeters long, with three prominent veins from the base, dull green on the upper surface and paler underneath. The compact shrub has small scale-like stipules and leaves with entire margins, creating a fine-textured appearance in mountain habitats.
Identification and appearance
Key characters: 54 sympatric species. Thorn-like twigs and 3-ribbed alternate leaves diagnostic.
Habitat and range
Habitat: Ridges, slopes, open conifer forests
Elevation: 365-3355 m
California counties: Kern, El Dorado, San Bernardino, Placer, Los Angeles, Fresno, Tulare, Riverside, Lassen, Mariposa, Siskiyou, Calaveras, Butte, Plumas, Mendocino, Tuolumne, Inyo, Alpine, Madera, Trinity, Nevada, Ventura, Sierra, Humboldt, Mono, Shasta, Lake, Amador, Glenn, Modoc, Tehama, Colusa, Yuba, Del Norte
Outside California: Oregon, Nevada, northern Baja California
Bloom period
Ceanothus cordulatus blooms May-Jul.
How to tell it apart
vs Rhamnus: Ceanothus has showy blue/white/pink flowers in dense clusters; Rhamnus has tiny inconspicuous greenish flowers.; vs Quercus: Ceanothus has showy flower clusters and small leaves; Quercus has acorns and distinctive lobed or toothed oak leaves.; vs Baccharis: Ceanothus has individual flowers with 5 separate petals; Baccharis has composite flower heads with tiny disc flowers.; vs Cercocarpus: Ceanothus has blue/white/pink flowers in clusters; Cercocarpus has tiny flowers with no petals and feathery fruiting tails.; vs Adenostoma: Ceanothus flowers have 5 distinct colored petals; Adenostoma has tiny white flowers and needle-like clustered leaves.
Frequently asked questions
Is Ceanothus cordulatus native to California?
Yes. Ceanothus cordulatus is native to California (recorded as native).
When does Ceanothus cordulatus bloom?
Ceanothus cordulatus blooms May-Jul.
Where in California does Ceanothus cordulatus grow?
Ceanothus cordulatus occurs in Kern, El Dorado, San Bernardino, Placer, Los Angeles, Fresno, Tulare, Riverside and other counties, at elevations of 365-3355 m.
What plant family does Ceanothus cordulatus belong to?
Ceanothus cordulatus is in the Rhamnaceae family, genus Ceanothus.
What habitat does Ceanothus cordulatus grow in?
Ceanothus cordulatus grows in Ridges, slopes, open conifer forests.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.