Astragalus gambelianus
Native to western North America, this drought-tolerant annual legume has slender stems to 30 cm, small compound leaves, dense black-hairy inflorescences of white to purple-tinged flowers, blooms from late February to June, grows in well-drained sandy or rocky arid soils in grassy and scrub habitats, is nitrogen-fixing with a deep taproot, supports pollinators, and is toxic to humans and pets.
Common Names
Gambel's Dwarf Milkvetch, Gambel's Milkvetch, Gambel's Locoweed, Milkvetch, Locoweed, Gambel's Milk-Vetch, Gambel's Dwarf, Dwarf Loco Weed
Summary
Gambel's Dwarf Milkvetch is an annual herb native to California with a range extending north to Oregon and south to Baja California. It has slender stems up to 30 cm tall and leaves less than 4 cm long with several oblong leaflets; an inflorescence carries up to 15 flowers that are white with a purple tinge and a black-hairy head, blooming from March through June; the fruit is a tiny rounded or oval legume pod a few millimeters long. It is a nitrogen-fixer.
It grows in full sun on well-drained sandy or rocky soils (pH 6.0–7.0), in open grassy areas as well as Coastal Sage Scrub, Foothill Woodland, and Southern Oak Woodland. Propagation is by seed with 30 days of stratification and 10–14 days for germination; seeds should be planted 1/4 inch deep and 12–18 inches apart. After establishment, it is drought-tolerant and requires minimal fertilization (slow-release if needed). It attracts pollinators and is toxic if ingested.
Lifecycle
Annual
Height
1-12 inches
Spread
18-24 inches
Sunlight Requirements
Ideally full sun.
Soil Type
Well-drained sandy soils
Soil Drainage
Well-drained sandy soils
Soil pH
6.0-7.0, slightly acidic to neutral
Bloom Color
White, Purple
Bloom Time
Spring and Summer
Leaf Lifecycle
Deciduous
Growth Rate
Moderate growth rate.
Seasons of Interest
Spring and Summer
Propagation Methods
Seeds, Cuttings, Division
Attracts Wildlife
Attracts butterflies
Taxonomy
- Taxonomic Rank
- Species
- Author
- E.Sheld.
- Publication
- Minnesota Bot. Stud. 1: 21 (1894)
Superior Taxa
- Kingdom
- Plantae
- Subkingdom
- Pteridobiotina
- Phylum
- Angiosperms
- Order
- Fabales
- Family
- Fabaceae
- Subfamily
- Papilionoideae
- Genus
- Astragalus
Synonyms
Astragalus gambellianus subsp. elmeri Astragalus elmeri Hesperastragalus gambellianus Astragalus nigrescens Astragalus gambelianus subsp. gambelianus Astragalus gambellianus var. elmeri Hesperastragalus elmeri