Ceanothus thyrsiflorus

Common Names

Blue Blossom, Blueblossom, California Lilac, Blue Brush

Summary

Blue Blossom, a broadleaf evergreen shrub in the Rhamnaceae family native to coastal California and Oregon canyons and wooded slopes, grows as an upright to rounded plant about 6–10 ft tall with an 8–10 ft spread and glossy evergreen leaves with three veins on the underside; it bears dense blue to violet flower clusters in spring (occasionally pale blue-white) that attract bees and other pollinators, and it is a nitrogen-fixer.

Cultivation notes: thrives in full sun to partial shade on well-drained soil and becomes drought-tolerant after establishment; avoid overwatering and prune after flowering; propagation by seeds (scarification) or semi-hardwood cuttings; hardy to USDA zones 7–8. In cultivation, it serves as a screen or large background planting, on slopes, and for erosion control, offering low-maintenance, drought-tolerant evergreen cover.

Lifecycle

Perennial

Height

6-10 feet

Spread

5-15 feet

Hardiness Zones

Zones 7-8

Sunlight Requirements

Ideally full sun or partial shade.

Soil Type

Well-drained loamy soil, pH 5.0–7.0, rich in organic matter

Soil Drainage

Well-drained soil

Soil pH

5.0-7.0

Bloom Color

Blue

Bloom Time

Spring (March–June)

Foliage Color

Green, glossy foliage

Fall Foliage Color

Green

Leaf Lifecycle

Evergreen broadleaf

Growth Rate

Fast

Seasons of Interest

Spring, Summer, Fall, Winter

Propagation Methods

Seeds and Cuttings

Attracts Wildlife

Attracts bees, butterflies, other pollinators, and birds