Juniperus occidentalis

Common Names

Western Juniper, Sierra Juniper

Summary

Western juniper is an evergreen conifer native to the western United States, typically 10–30 ft tall with a trunk up to 3 ft in diameter, slow-growing and long-lived, with dense, aromatic green to gray-green foliage. Juvenile leaves are 5–10 mm long and needle-like, while adult leaves are 1–2 mm long and scale-like; cones are blue-brown, berry-like, 5–10 mm in diameter, containing 1–3 seeds and maturing in about 18 months; it can appear as a shrub or small tree and often grows on dry, rocky sites in mountains and foothills, sometimes reaching krummholz form at exposed high elevations.

Culture favors full sun to partial shade and well-drained sandy or loamy soils, tolerates drought and performs poorly in clay soils; growth is slow, pruning in winter to maintain shape is common; propagation is via seed (slow) or cuttings (common in cultivation), with germination best on bare mineral soil after warm stratification (20–27°C, 45–90 days) followed by cold stratification (~4°C); durable wood used for fence posts and furniture, and cones and foliage provide habitat and food for wildlife.

Lifecycle

Perennial

Height

13-50 feet

Spread

1.5-5 feet

Hardiness Zones

Zones 4-8

Sunlight Requirements

Ideally full sun; tolerates partial sun to partial shade; not thrive in full shade.

Soil Type

Well-drained sandy or loamy soils, dry, rocky conditions, avoid clay soils

Soil Drainage

Well-drained

Soil pH

6.0-8.5, Neutral to mildly alkaline soils, Slightly acidic; tolerates slightly alkaline soils up to pH 8.0

Bloom Color

Blue or purple with a glaucous bloom.

Bloom Time

Spring

Foliage Color

Gray-green to dark green

Fall Foliage Color

Evergreen (no fall color change)

Leaf Lifecycle

Evergreen needle

Growth Rate

Slow-growing; early growth about 1.18–1.58 inches per year, later growth about 3.54–6.57 inches per year (canopy ~6.6 inches per year; subcanopy ~3.5 inches per year), with acceleration after about 15–25 years.

Seasons of Interest

Spring and Fall

Propagation Methods

Seeds, Cuttings, Layering

Attracts Wildlife

Attracts birds