Allium macrum

Common Names

Rock Onion

Summary

Rock onion is native to the northwestern United States, specifically Oregon and Washington. It is a perennial bulbous herb with two slender basal leaves up to 38 cm long, a solitary erect scape up to about 30 cm tall supporting an umbel of 10–20 flowers; bulbs are globose to oval (0.6–2 cm long) and flowers are white to pale pink with a green stripe along each tepal and red midribs, blooming April–May, growing in barren, gravelly soils in shrub-steppe at elevations of 100–1400 m, with pollinators including bumblebees, bees, flies, and hummingbirds.

Cultivation notes: as a native of Oregon and Washington, it thrives in barren, gravelly soils in shrub-steppe at 100–1400 m and is a perennial with a solitary scape up to about 30 cm tall and two slender leaves; it bears an umbel of 10–20 flowers that bloom April–May, and is not of conservation concern, with pollination by bumblebees, bees, flies, and hummingbirds.

Lifecycle

Perennial

Height

3.5-3.9 inches

Spread

4 inches

Hardiness Zones

Zones 6-6

Sunlight Requirements

Ideally full sun.

Soil Type

Gravelly soils

Soil Drainage

Well-drained

Bloom Color

White to pale pink

Bloom Time

Spring

Foliage Color

Gray-Green

Fall Foliage Color

Grayish-Green

Leaf Lifecycle

Deciduous

Growth Rate

Perennial

Seasons of Interest

Spring and Summer

Propagation Methods

Seeds, Self-seeding

Attracts Wildlife

Bees, Hummingbirds, Other pollinators, Birds