Asclepias speciosa, commonly called Showy Milkweed, is a rough, robust perennial which commonly occurs on dry slopes, open woodland areas, roadsides, waste areas and along streams in western North America. It typically grows 2-4' tall on stout, upright stems with velvety, broad-oblong to broad-ovate, gray-green leaves (to 8" long) with conspicuous veining. Globular clusters (umbels to 3" across) of fragrant, pinkish-white to pinkish-purple, star-like flowers appear mostly in the upper leaf axils over a long bloom period from late spring well into summer. Stems and leaves exude a milky sap when cut or bruised. Flowers give way to prominent, rough seed pods (2-3" long) which split open when ripe releasing their numerous silky-tailed seeds for dispersal by the wind. Seed pods are valued in dried flower arrangements. Flowers are a nectar source for many butterflies and leaves are a food source for monarch butterfly larvae (caterpillars).
It is somewhat more pink that the common milkweed, with larger flower trusses. It is easily grown in average, dry to medium, well-drained soils in full sun. Drought tolerant. Does well in poor, dryish, gravelly soils. Easily grown from seed, and may self-seed in the landscape if seed pods are not removed prior to splitting open. Once established, it is best to leave plants undisturbed because they develop deep taproots which make transplanting difficult.
Information adapted from: Missouri Botanical Garden
Photo from: Missouri Botanical Garden