Asclepiadaceae: Asclepias speciosa
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Family Name
Asclepiadaceae
Common Name
Showy milkweed
Native American Name
Lakota: waȟpé thíŋpsila
Description
Asclepias speciosa is a perennial herb with milky white sap, growing from a deep rhizome with solitary stems that are simple or occasionally branched, growing 50 to 100 cm in height and densely covered in hairs toward the top. The simple leaves are usually opposite with a short petiole 2-13 mm in length. The blades are entire, broadly lanceolate to ovate. 8-20 cm long and 2.5-10 cm wide, with a thick covering of hairs on the underside. The inflorescences are few to several in the upper leaf axils, each coming from a 2-10 cm peduncle 1-3 cm long hat are having 10 to 40 flowers attached by a 1-3 cm long pedicel that is covered with short hairs. The flowers are 15-28 mm long, the calyx is green to purple, covered with hairs and with 5 lobes that are 5-7 mm long. The purple to rose colored corolla lobes are rounded, reflexed and 9-15 mm long the apex is attenuated looking like a crown. The fused stamens and pistil os pale rose to pinkish-cream colored, broadly obconic 1-1.5 mm tall a\nd 2.5-3.3 mm wide. The fruit are erect follicles that are 7-11 cm long and 2-3 cm wide. The sees are ovate 6-9 mm long with long white to brownish hairs. Showy milkweed blooms from May through August on the banks of lakes, ponds and streams or moist areas on prairies throughout much of South Dakota. Showy milkweed and common milkweed are very similar. They can be distinguished by their flower petals, with A. speciosa having longer narrower petal lobes that give the flower the appearance of a crown.
Horticulture Notes
Seed Collection: Seeds turn brown and are released from the pods over an extended period. The seeds in open pods often have milkweed buds and care should be taken or they will consume stored seeds. 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.
Soil: Tolerate a wide range of soils but prefers a well-drained sandy loam.
Water: Moist to dry conditions.
Additional Notes
Showy milkweed is an attractive addition to a native plant garden and an important food source for the monarch butterfly caterpillar. The flowers attract butterflies, bumblebees and hummingbirds to the garden. Young shoots, leaves and seed pods are all edible if cooked. Extracting the milky latex is accomplished by placing plant materials in cold water and bringing them to a boil. They can then be steamed, boiled or fried.