Ceanothus cyaneus
Lakeside ceanothus
(c) James C. Davis, some rights reserved (CC BY-SA) · licence
Family: Rhamnaceae · Type: Shrub · Native
Conservation status: CNPS 1B.2
Ceanothus cyaneus (Lakeside ceanothus) is a native California shrub in the Rhamnaceae family, recognized by . Large panicles of bright blue flowers and glaucous alternate leaves diagnostic.
Lakeside ceanothus is a rare (CNPS 1B.2) California native shrub found in southern Peninsular Ranges near San Diego County in chaparral on slopes and ridges at elevations of 45 to 1,050 meters. Flowering from April to June, this plant produces bright blue flowers in panicle-like clusters 5 to 30 centimeters long. Growing as an open shrub less than 3 meters tall with ascending to erect flexible green stems, it has distinctively angled twigs with ridged internodes. Its alternate evergreen leaves are approximately ovate-elliptic, 15 to 45 millimeters long, with green upper surfaces and pale green glaucous undersides featuring 23 to 58 small serrated leaf edges. The compact shrub has a distinctive appearance with its bright blue flowers and finely textured foliage.
Identification and appearance
Key characters: 23 sympatric species. Large panicles of bright blue flowers and glaucous alternate leaves diagnostic.
Habitat and range
Habitat: Slopes, ridges, chaparral
Elevation: 45-1050 m
Outside California: northern Baja California
Bloom period
Ceanothus cyaneus blooms Apr-Jun.
Conservation status
CNPS 1B.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 cyaneus native to California?
Yes. Ceanothus cyaneus is native to California (recorded as native).
When does Ceanothus cyaneus bloom?
Ceanothus cyaneus blooms Apr-Jun.
What plant family does Ceanothus cyaneus belong to?
Ceanothus cyaneus is in the Rhamnaceae family, genus Ceanothus.
Is Ceanothus cyaneus rare or endangered?
Ceanothus cyaneus carries California Rare Plant Rank 1B.2, state rank S2.
What habitat does Ceanothus cyaneus grow in?
Ceanothus cyaneus grows in Slopes, ridges, chaparral.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos · CDFW CNDDB
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.