Astragalus brauntonii

Common Names

Braunton's Milk-Vetch, Braunton's Milkvetch

Summary

Braunton's milkvetch is a federally endangered perennial herb endemic to southern California, occurring in coastal sage scrub, chaparral, and grasses on carbonate soils in Los Angeles, Orange, and Ventura counties. It grows up to about 1.5 m tall from a woody caudex, with woolly stems and pinnate leaves of 25–33 leaflets; a dense spike of up to 60 lilac flowers is produced, followed by a two-chambered pod. Fire-adapted and a post-disturbance pioneer, it relies on disturbance to recruit from a long-lived soil seed bank and is visited by native Megachile bees and Bombus spp.

Cultivation and landscape use emphasize maintaining open, light-rich habitats, with germination triggered by heat or scarification and seeds persisting in a soil seed bank after disturbance. It prefers carbonate soils in disturbed chaparral and coastal scrub habitats; threats include habitat loss from development and fragmentation. As a nectar source for megachilid bees, it supports pollinators and is a candidate for conservation and restoration in southern California landscapes.

Lifecycle

Perennial

Height

2-5 feet

Sunlight Requirements

Ideally full sun.

Soil Type

Well-draining carbonate soils

Soil Drainage

Well-drained sandy soils with low organic matter.

Soil pH

No information on ideal soil pH.

Bloom Color

Lilac

Bloom Time

Spring and Summer

Foliage Color

Green

Fall Foliage Color

Yellow

Leaf Lifecycle

Deciduous

Growth Rate

Rapid growth

Seasons of Interest

Spring and Summer

Propagation Methods

Seeds, Caudex-based vegetative regeneration (possible; undocumented)

Attracts Wildlife

Bees, butterflies, and other pollinators are attracted.