Ceanothus (Ceanothus thyrsiflorus): Fragrant Blue Blossoms for West Coast Gardens

Evergreen wild lilac (Ceanothus thyrsiflorus) is iconic to the U.S. West Coast, thriving in hot, dry summers and cool, wet winters. Its honey-scented blue flower clouds in April–May draw pollinators and hummingbirds. Foliage has a faint resinous scent, especially on warm days. Fast-growing once established.

Botanical Name: Ceanothus thyrsiflorus
Common Names: Blueblossom, wild lilac
Origin: Coastal and intermountain North America, Oregon to California
Hardiness: USDA zones 7–9 (hardy to 0°F)
Water Needs: Thrives in dry-summer/wet-winter climate; no supplemental summer water once established
Light Requirements: Partial to full sun
Mature Size: 3–20 feet tall, depending on cultivar

Benefits and Tolerances

Blossoms provide nectar and pollen; seeds in fall. Nitrogen-fixing.

Seasonal Interest

Fluffy blue to white honey-scented flowers in May.

Distinguishing Traits

Showy white or blue flowers (late April to early June) are honey-scented and attract birds, butterflies, and pollinating insects. Fixes nitrogen in soil.

Design Uses

Many cultivars range from groundcovers (3 ft tall, 6 ft wide) to small trees (20 ft tall, 12 ft wide). Evergreen and cold-hardy among Ceanothus species, making a fine informal hedge providing wildlife shelter, nectar, and pollen. Perfect for out-of-the-way areas beyond irrigation reach.

Planting Notes

Fast-growing but sometimes short-lived (10–15 years, longer in ideal conditions). Provide well-drained soil, avoid fertilizer, minimal or no summer water. Cultivars include ‘Repens’ (3x9 ft), ‘Victoria’ (8–10 ft), ‘Skylark’ (10–15 ft, RHS Award), ‘Snow Flurry’ (10–15 ft, white), ‘Oregon Mist’ (15 ft, deeper blue).

Photos by Stan Shebs and A. Barra