Blue Blossum is an evergreen shrub or small tree native to coastal regions from Santa Barbara to southern Oregon. It grows 6-12 feet tall and wide, with bright to dark green, shiny foliage and large bunches of blue to white flowers in spring. As one of the largest Ceanothus species, it can be used as a small tree, hedge, or foundation plant and provides habitat for birds and butterflies. It grows well in full sun or partial shade with well-drained soil and occasional water once established.

1. * Blue Blossum – Ceanothus thyrsiflorus
(see-uh-NO-thus THUR-SEE-FLOR-us)
Family: Rhamnaceae (Buckthorn Family)
Native to: Coastal Ranges from Santa Barbara Co. to southern Oregon; old beach dunes and beach
bluffs, wooded slopes and canyons. Soils vary from very sandy to clay/adobe.
Growth characteristics: evergreen shrub/tree
mature height: 6-12+ ft. mature width: 8-12 ft.
Large evergreen shrub or small open tree with a short trunk. Foliage bright to dark green, shiny,
very neat and ‘garden-like’ in appearance. Many spreading branches give a nice, rounded shape.
Blooms in spring (Apr./June). Large bunches of tiny flowers – very showy. Color
ranges from bright blue to white. Fruits are small, sticky, loved by birds.
Blooms/fruits:
Uses in the garden: As once of the largest Ceanothus, this species can be used as a small tree, as a
screen or large hedge or as a large foundation plant. It looks great along walls and fences, but also
makes a nice ‘living wall’ as a background for other native plants. Fast growing. Fine near beach or
inland. Cultivar ‘Skylark’ is compact, blue-flowered, takes heat. ‘Snowflurry’ is large, whiteflowered, best along coast or with some shade inland. Deer will eat foliage.
Sensible substitute for: Non-native evergreen flowering shrubs.
Attracts: Excellent bird habitat: provides cover and seeds for food. Flowers attract butterflies;
larval food for Pale Swallowtail.
Requirements:
Element
Sun
Soil
Water
Fertilizer
Other
Requirement
Full sun (coast); part-shade in hot gardens
Any well-drained soil; any local pH including fairly acid (to pH 4.5)
Zone 2 (water deeply when soil is dry) once established; keep crown dry
None needed
Easy to grow. Dislikes heavy pruning – don’t cut branches bigger than pencil
diameter. If training as a tree, begin to train in first year. Pruning (if any) in spring after flowering.
Management:
Propagation: from seed: hot water soak; cold treatment
by cuttings: yes
Plant/seed sources (see list for source numbers): 1, 3, 5, 8, 9, 11, 13, 14, 20, 24
* Native to CA but not to Western L.A. Co.
2/14/11
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