Fabaceae: Astragalus racemosus
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Family Name
Fabaceae
Common Name
Alkali milkvetch, Creamy poison vetch
Native American Name
Lakota: pȟežúta ská hú, šuŋkléža hú
Description
Astragalus racemosus is a perennial herb growing from a branched caudex, with multiple, often branched, erect to ascending stems, 15-70 cm tall that are thinly to densely covered with appressed hairs. The alternate, compound odd-pinnate leaves are4-15 cm long, with short petioles below and sessile above, with stipules 3-12 mm long. there are 11-31 leaflets, 1-4 cm long, the lower leaves having broader lance-elliptic leaflets, and the upper leaves with narrower lanceolate leaflets. The inflorescence consist of axillary racemes with 15-70 papilionaceous flowers on peduncles 3-11 cm long. The flowers are generally nodding on pedicels 2-3.5 mm long. The calyx tube is covered in white, appressed hairs, .bell-shaped, 5-7 mm long, sometimes swollen at the base with 5 awn-like lobes, 2-10 mm long. the 5 petals are white to cream colored with purplish tips and or streaks. The banner is 6-12 mm long, the clawed (constricted at the base) wings 12-19 mm long, and the clawed keel 10-16 mm long. The fruit are triangularly compressed legumes, 3.5-7 cm long, 3-6 mm in diameter, with a stipe on the end that is up to 7 mm long. Alkali milkvetch blooms from May to July on poorer soils in prairies, plains, hillsides and in stream valleys in western South Dakota.
Horticulture Notes
Seed collection: Pods can be collected in Summer when they turn tan and the seeds become dark brown.
Germination: Fall sowing or plant in early spring while the ground is still cold.
Light: Full sun.
Soil: Well drained sands to clays. Will tolerate alkali soils.
Water: Medium to dry.
Additional Notes
Creamy poison vetch can be toxic to livestock, accumulating selenium from alkali soils that adversely effects the nerves and hooves of horses and other animals. The plants are attractive and when planted in large clusters, provide a striking display of white flowers with a purplish tinge. The flowers attract many native bumblebee species and the leaves host the larva of native butterflies.