rosy bird's-foot trefoil

Hosackia rosea Eastw.

Rosy bird’s-foot trefoil grows from creeping underground stems and sends up smooth, hollow shoots. These may stand upright or spread outward, reaching roughly twenty centimetres to a metre. It is a perennial of the pea family, with flowers that combine a pale background and deeper pink lines. University of Washington Burke Herbarium: Hosackia rosea

Botanical name

Kew accepts Hosackia rosea Eastw., with Lotus aboriginus Jeps. listed as a synonym of the same species. Kew POWO: Hosackia rosea

Recognizing the plant

Each compound leaf carries nine to fifteen oblong or spoon-shaped leaflets along a central axis, with one leaflet at the tip. Their upper surfaces are bright green and the undersides have a pale, waxy appearance. Long flower stalks support umbrella-like clusters of seven to twenty blossoms. Each pea-shaped flower is about eight to thirteen millimetres long and sits above a tubular calyx with five short triangular teeth. Flattened seedpods reach about two and a half to four and a half centimetres. University of Washington Burke Herbarium: Hosackia rosea

Bloom window

Washington flora account

Flowering is recorded from May through July. University of Washington Burke Herbarium: Hosackia rosea

Native range

The native range extends from Washington south through Oregon to California. The Washington flora records it west of the Cascade crest, growing in moist woods and beside streams. Kew POWO: Hosackia rosea University of Washington Burke Herbarium: Hosackia rosea

Botanical sources

Reviewed 2026-10-11. Seasonal development varies with location and growing conditions.