Asclepiadaceae: Asclepias viridiflora
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Family Name
Asclepiadaceae
Common Name
Green milkweed
Native American Name
Lakota: húčhiŋška
Description
Asclepias viridiflora is a perennial herb, with milky white sap, having 1 or 2 stems growing from a taproot, with the stems only occasionally branched, stout and 10 to 60 cm tall. The simple leaves are opposite, or nearly so, to alternate. The blades are entire, variable in shape from linear to almost round, ascending to widely spreading, 4-14 cm long and 1-6 cm wide and having a few to a dense covering of whitish short woolly hairs. There are 1 to many inflorescences scattered in the axils of the leaves of the upper half of the stem. Each umbellate cluster contains 20-80 flowers, each with a short (5-15 mm) pedicel attached to a 2-20 mm peduncle. The flowers are 9.5-12.5 mm long with a green to purple tinged calyx with lobes 2-3 mm long. The corolla is pale green, with reflexed lobes 5.7-7 mm long. The fused stamens and pistil is also pale green and 1.2-1.5 mm tall and 1.2 -1.4 mm wide. The fruit is a follicle, swollen in the middle and tapered at both ends, 7-15 cm long and about 2 cm in the widest section. The seeds are obovate, 6-7.5 mm long with long tan hairs attached. Flowering occurs from June through August. Green milkweed grows on sandy to rocky soils in prairies throughout much 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: Seeds are the only reported means of propagation for this species.
Light: Full sun.
Soil: Sandy, clay or rocky soils.
Water: Medium to dry conditions.
Additional Notes
Though not a showy milkweed, green milkweed is an interesting specimen in a native plant garden with its wavy foliage and green flowers. Like other milkweeds it serves as a host to monarch butterfly caterpillars and its flowers attract butterflies and native bees.