Ceanothus rigidus
Monterey ceanothus
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Family: Rhamnaceae · Type: Shrub · Native
Conservation status: CNPS 4.2
Ceanothus rigidus (Monterey ceanothus) is a native California shrub in the Rhamnaceae family, recognized by very small round leaves and coastal sandy habitat.
Monterey ceanothus is a California native shrub with a rank of 4.2, found in the central Coast Ranges in sandy substrates, chaparral, and closed-cone pine forest at elevations below 400 meters. Flowering from March to May, this plant produces blue to lavender flowers occasionally appearing white, clustered in compact umbel-like formations. Growing as a dense, mound-like to slightly erect shrub less than 1.5 meters tall, it features erect to spreading stems with brown to gray-brown twigs. Its opposite, evergreen leaves are widely obovate and rounded, dark green and shiny on the upper surface, measuring 4 to 10 millimeters long with a rounded or truncate tip and occasionally bearing 5 to 9 sharp teeth. The compact shrub produces smooth fruits approximately 4 to 6 millimeters wide with small, smooth horns less than 1 millimeter long.
Identification and appearance
Key characters: 21 sympatric species; key features are very small round leaves and coastal sandy habitat
Habitat and range
Habitat: Sandy substrates, chaparral, closed-cone-pine forest
Elevation: < 400 m
California counties: Monterey, Los Angeles, Marin, San Luis Obispo, San Benito, Santa Barbara, Santa Cruz
Bloom period
Ceanothus rigidus blooms Mar-May.
Conservation status
CNPS 4.2
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 rigidus native to California?
Yes. Ceanothus rigidus is native to California (recorded as native).
When does Ceanothus rigidus bloom?
Ceanothus rigidus blooms Mar-May.
Where in California does Ceanothus rigidus grow?
Ceanothus rigidus occurs in Monterey, Los Angeles, Marin, San Luis Obispo, San Benito, Santa Barbara, Santa Cruz, at elevations of < 400 m.
What plant family does Ceanothus rigidus belong to?
Ceanothus rigidus is in the Rhamnaceae family, genus Ceanothus.
Is Ceanothus rigidus rare or endangered?
Ceanothus rigidus carries California Rare Plant Rank 4.2, state rank S4.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
Last updated 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.