Allium tuolumnense

Common Names

Rawhide Hill Onion, Serpentine Onion

Summary

Rawhide Hill onion is a rare California-endemic perennial bulbiferous herb native to Tuolumne County, growing in serpentine soils. It forms a reddish-brown bulb 1–2 cm long, with a slender erect stem up to 50 cm tall and usually a single leaf; a hemispheric inflorescence of 20–60 flowers sits on pedicels 1–2 cm long, each flower just under 1 cm wide with six white or pink oval tepals, six stamens, and a six-pointed crested ovary; foliage is green with a grassy texture.

It tolerates full sun to sun–dappled shade and occasional to low water, is drought-tolerant once established, and prefers lean, gritty, rocky, well-drained soil; hardy in USDA zones 5a–10b; commonly used as a container plant, edging plant, or in rock gardens, and is fragrant while supporting bees, caterpillars, and butterflies.

Lifecycle

Perennial

Height

19.5-20 inches

Spread

2-12 inches

Hardiness Zones

Zones 5a-10b

Sunlight Requirements

Ideally full sun or partial shade.

Soil Type

Serpentine soils, well-drained.

Soil Drainage

Well-drained soil, serpentine soils

Bloom Color

White or pink

Bloom Time

Spring

Foliage Color

Green

Fall Foliage Color

Green

Leaf Lifecycle

Deciduous

Seasons of Interest

Spring (Mar–May)

Attracts Wildlife

Attracts bees, butterflies, and other pollinators