Ceanothus cordulatus

Common Names

Mountain Whitethorn, Whitethorn Ceanothus, Whitethorn, Snowbush

Summary

Mountain Whitethorn is an evergreen shrub native to California and nearby Oregon, Nevada, and Baja California, growing on rocky ridges and slopes in chaparral and conifer or mixed evergreen forests at elevations of 400–3400 m. It forms a spreading to ascending habit about 0.5–1.5 m tall, with thorn-tipped, rigid branchlets and small evergreen leaves 10–30 × 6–18 mm that are three-ribbed from the base. Dense axillary inflorescences are umbel-like or racemelike, 1.2–2(–4) cm long, bearing white flowers (occasionally pink) with a penetrating fragrance, and the fruit is a rough, ridged capsule 3.5–5 mm wide containing a seed; it is a nitrogen-fixing plant via Frankia, contributing soil nitrogen.

Culture and uses: prefers sun to partial shade with very well-drained soils; sandy or loamy soils with pH 5.0–7.0 and drainage ranging from fast to slow; drought-tolerant once established and suitable for high-elevation landscapes, bank stabilization, and hedges, with potential as ground cover up to about 12 ft in diameter. Propagation by seed is possible with hot-water pretreatment followed by stratification, with quick method yielding about 25% germination.

Lifecycle

Perennial

Height

2-5 feet

Spread

4 ft 11 in - 9 ft

Hardiness Zones

Zones 5-7

Sunlight Requirements

Ideally full sun. Tolerates partial shade.

Soil Type

Well-drained soil, sandy to loamy.

Soil Drainage

Well-drained soil

Soil pH

5-6.5

Bloom Color

White

Bloom Time

Spring and Summer

Foliage Color

Green, ranging from pale green to grayish green

Fall Foliage Color

No fall color

Leaf Lifecycle

Evergreen broadleaf

Growth Rate

Very slow at lower elevations; fast growing at higher elevations.

Seasons of Interest

Spring and Summer

Propagation Methods

Seeds, Layering, Vegetative propagation via root suckering

Attracts Wildlife

Attracts birds, butterflies, and other pollinators