Ceanothus thyrsiflorus var. thyrsiflorus
Blue blossom
Photo: parent species Ceanothus thyrsiflorus · (c) Henrik Kibak, some rights reserved (CC BY) · licence
Family: Rhamnaceae · Type: Tree · Native
Ceanothus thyrsiflorus var. thyrsiflorus (Blue blossom) is a native California tree in the Rhamnaceae family, recognized by smooth twigs and flatter leaf margins.
Blue blossom is a California native tree found in the North Coast, Klamath Ranges, southern North Coast Inner, North Coast Outer, Central Coast, San Francisco Bay Area, and southern Coast Ranges in bluffs, slopes, canyons, chaparral, coastal scrub, and closed-cone pine forests at elevations below 800 meters. Flowering from March to June, this plant produces blue to white flowers in dense, rounded clusters. Growing with upright branches 3 to 5 meters tall, it forms a multi-stemmed shrub or small tree with relatively smooth, grayish twigs. Its leaves are oblong-ovate to elliptic, with margins slightly rolled under, creating a subtle, compact appearance. In mature stands, blue blossom creates dense, rounded thickets that provide important habitat and visual structure in coastal California landscapes.
Identification and appearance
Key characters: 54 sympatric species; key features are smooth twigs and flatter leaf margins
Habitat and range
Habitat: Bluffs, slopes, canyons, chaparral, coastal scrub, closed-cone-pine forest
Elevation: < 800 m
California counties: Marin, Humboldt, San Luis Obispo, Monterey, Santa Barbara, Mendocino, Santa Cruz, San Francisco, San Mateo
Outside California: southwestern Oregon, northern Baja California
Bloom period
Ceanothus thyrsiflorus var. thyrsiflorus blooms Mar-Jun.
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 thyrsiflorus var. thyrsiflorus native to California?
Yes. Ceanothus thyrsiflorus var. thyrsiflorus is native to California (recorded as native).
When does Ceanothus thyrsiflorus var. thyrsiflorus bloom?
Ceanothus thyrsiflorus var. thyrsiflorus blooms Mar-Jun.
Where in California does Ceanothus thyrsiflorus var. thyrsiflorus grow?
Ceanothus thyrsiflorus var. thyrsiflorus occurs in Marin, Humboldt, San Luis Obispo, Monterey, Santa Barbara, Mendocino, Santa Cruz, San Francisco and other counties, at elevations of < 800 m.
What plant family does Ceanothus thyrsiflorus var. thyrsiflorus belong to?
Ceanothus thyrsiflorus var. thyrsiflorus is in the Rhamnaceae family, genus Ceanothus.
What habitat does Ceanothus thyrsiflorus var. thyrsiflorus grow in?
Ceanothus thyrsiflorus var. thyrsiflorus grows in Bluffs, slopes, canyons, chaparral, coastal scrub, closed-cone-pine forest.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
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.