Astragalus preussii
A southwestern United States native legume with pinnate leaves bearing 7–25 leaflets, forming large clumps up to two feet tall and bearing dark red to purple flowers in racemes, typically found in disturbed sandy habitats on selenium-rich soils where it hyperaccumulates selenium and is poisonous to mammals.
Common Names
Preuss' Milkvetch
Summary
Preuss' milkvetch is a native perennial herb in the Fabaceae that grows as an upright plant up to about 4–14 inches tall, with glabrous, pinnately compound leaves bearing 5–25 small oval leaflets. Flowers occur in spring as 4–22 ascending blossoms with pink-purple to pale petals; the banner measures 14–24 mm and is recurved, while the keel is 11–19 mm. Fruits are inflated, oblong-ellipsoid pods that are glabrous or minutely hairy. The plant occurs in desert habitats on clay flats, gravels, and canyon talus within the southwestern United States, including the Colorado Plateau region, and a distinctive feature is an unpleasant odor produced by selenium accumulation.
Flowering occurs from March to May, and the plant is adapted to desert or disturbed sites with well-drained soils. It is native to the southwestern United States and can be used in wildlife-friendly plantings, as it supports caterpillars and butterflies.
Lifecycle
Perennial
Height
4-24 inches
Spread
24 inches
Sunlight Requirements
Ideally full sun.
Soil Type
Selenium-bearing alkaline soils.
Soil Drainage
Well-drained
Soil pH
Alkaline soils (pH > 7)
Bloom Color
Pink to Purple
Bloom Time
Spring
Foliage Color
Green to yellowish-green
Fall Foliage Color
Green to yellowish-green
Growth Rate
Not specified
Seasons of Interest
Spring
Propagation Methods
Seeds
Attracts Wildlife
Attracts bees and butterflies
Taxonomy
- Taxonomic Rank
- Species
- Author
- A.Gray
- Publication
- Proc. Amer. Acad. Arts 6: 222 (1865)
Superior Taxa
- Kingdom
- Plantae
- Subkingdom
- Pteridobiotina
- Phylum
- Angiosperms
- Order
- Fabales
- Family
- Fabaceae
- Subfamily
- Papilionoideae
- Genus
- Astragalus
Inferior Taxa
Astragalus preussii var. latus Astragalus preussii var. laxiflorus Astragalus preussii var. preussii