Asclepias speciosa (Showy Milkweed)

Plant Description: Asclepias speciosa is herbaceous perennial spread by rhizomes. The whole plant is grayish and pubescent, except for a few specimen that sometimes are free from hair. From June-August, during bloom, showy milkweed is easily recognized by the striking beauty of its large pink to reddish purple inflorescence. The flowers are densely woolly and arranged in an intricate umbel structure, each one composed of 15 to 25 blossoms. Individual blossoms bear 5 petals each and are sharply bent backwards. The stems are hollow and ooze with milky sap. The long (up to 6 inches) felty leaves occur in opposite pairs, and vary in shape from ovate to oblong to cordate (heart-shaped). After flowering is completed, hairy pods filled with brown, flat seeds are produced.

• Height: 3-5ft
• Width: 2-4ft
• Watering needs: Dry-Medium moisture
• Sun needs: Full sun
• Soil needs: Loamy to sandy
• Bloom Time: June-August

Landscape Use and Ecological Function: This Willamette Valley native is widely scattered at low elevations and dry climates. Asclepias speciosa is common east of the Cascades. Its also present in low to mid elevations, up to 6500 feet, of other suitable regions ranging from California to British Columbia and east to the Mississippi Valley. 

We recommend growing this plant in meadowscapes and in conventional or ornamental gardens. Blossoms are visited by multiple insects, including the western monarch butterfly. Asclepias speciosa has a relatively long bloom period, 2 to 3 months, making it a reliable source of nectar for monarchs. The plant’s large, thick leaves are also great to sustain the butterfly’s offspring. The milky juice of Asclepias contain poisonous resinoids and glycosides that, when ingested by the insects, help them to repel hungry predators such as birds and small mammals.