Asclepiadaceae : Asclepias verticillata
Files
Family Name
Asclepiadaceae
Common Name
Whorled milkweed
Native American Name
Lakota: waȟpé thíŋpsila iyéčheča
Description
Asclepias verticillata is a perennial herb containing milky white sap, with 1 to a few stems arising from a fibrous crown, occasionally branched and 35-90 cm tall. The sessile leaves are whorled with 3-6 leaves per node. The blades are entire, linear, 1.5 to 8 cm long and about 1 mm wide. The inflorescences are few to many in the axils of the upper leaves, each containing 6-20 flowers. Flower buds appear yellowish but produce white to greenish white flowers. Each flower is attached to a short peduncle (1-4 cm long) by a 5-11 mm pedicel. Calyx lobes are green to purple tinged 1-2.5 mm long and the corolla lobes are white to greenish white, reflexed and3.5-4.5 mm long. The fruit are erect follicles 8-10.5 cm long and < 1 cm wide. The ovate seeds are 5-6 mm long with long white hairs. Whorled milkweed blooms from June through September in the prairies, flood plains and open woods of South Dakota.
Horticulture Notes
Seed Collection: Seeds turn brown and are released from the pods over an extended period. Unopened brownish pods that split when gently squeezed are the best source.
Germination: Seeds require 30 days of cold moist stratification before planting in the spring. Seeds planted in the fall will germinate in the following spring.
Vegetative propagation: Established plants can be divided in late spring and transplanted.
Light: Full sun to partial shade.
Soil: Sandy, clay or rocky soils.
Water: Medium to dry conditions.
Additional Notes
Whorled milkweed can make an interesting addition to a garden. The flowers attract bumblebees and honeybees, and its leaves provide food for monarch butterfly caterpillars. This plant is toxic to livestock and is considered a weed in some areas.