A midsummer display of flowers as emphatically orange as the monarch butterflies that feast on their nectar adorn wide-open spaces wherever wild butterfly weed (Asclepias tuberosa) grows. Named for the sustenance it provides monarchs and their gaudy, black-, white- and yellow-striped caterpillars, this 1 1/2- to 2 1/2-foot-tall perennial thrives in dry, sunny sites across U.S. Department of Agriculture plant hardiness zones 3 through 9, where it is hardy. Plant it for simple-care color and a continuing parade of butterflies and hummingbirds
Native to hillsides, woods and prairies from the U.S. Atlantic and Gulf coasts to the Great Lakes and Rocky Mountains, butterfly weed thrives in any well-drained soil, including limestone-based soil. In fall, the plant’s showy, 3- to 6-inch brown seedpods split open as their hundreds of feather-tailed seeds make a wind-borne exodus to new sites.
Although butterfly weed belongs to the Milkweed (Asclepiadaceae) family, its upright stems and stiff, lance-shaped leaves don’t contain the milky-white sap responsible for the family name. Growing in clumps that spread up to 3 feet, the plant boasts flat, 2- to 5-inch clusters of yellow-orange to tangerine-orange blooms. Each tiny flower opens from a brilliant-red-orange bud. The flowers appear even brighter against butterfly weed’s deep-green foliage. They make striking additions to floral arrangements, especially when contrasted with blue or purple flowers.
Placement and Care
Butterfly weed’s long taproots protect the plant through long dry spells, but they also mean the plant resents transplanting. Provide the plant a permanent location with poor to averagely fertile, well-draining soil and full sun exposure. When planted in fall, it sets buds for the following summer during winter’s cool days. Reduce the risk of crown rot by setting the butterfly weed in a planting hole with its crown slightly above the soil line. Allow 18 inches between multiple plants, and water the soil whenever its top 3 or 4 inches are dry to the touch. Butterfly weed’s tolerance of poor to average soil makes fertilizing it unnecessary. Removing the first flush of flowers after those blooms fade stimulates a repeat flush of flowers in about one month.
Monarchs aren’t the only orange insects to find butterfly weed irresistible. Colonies of yellow-orange oleander aphids (Aphis nerii), also known as milkweed aphids, envelop the plant’s stems and leaves as they feed on sap. They excrete massive amounts of clear, gooey waste called honeydew. The honeydew attracts black, sooty mold that covers the plant in layers of powdery, sootlike fungal strands. Treat small aphid infestations by pruning the infested stems or dislodging the pests with a strong spray of water. Manage heavier aphid infestations with applications of insecticidal soap or horticultural oils, sprayed to saturate the colonized stems and leaves. Always use those products according to their labels’ specifications.