Plant of the Month June 2019: Butterfly-weed

Butterfly-weed (Asclepias tuberosa), probably the most popular garden milkweed, has incredibly showy, brilliant orange to red-orange and even yellow flowers. In June and July or sometimes later, large flat-topped clusters of brightly colored flowers top softly fuzzy stems. Like other milkweeds, Individually distinctive flower parts are united with the central style into a cup-like structure, surrounded by a skirt of petals. The showy flowers are rich in nectar and have globs of waxy pollen that attract a multitude of pollinators. 

Flowers are followed by 3 -4” long, narrow, hairy seedpods, held upright at the ends of stems and filled with tufted seeds of silky white hairs that are dispersed by wind. Butterfly-weed differs from other milkweeds in several characteristics. This short perennial typically reaches only 1 – 2.5’ in height with alternate, narrow, leathery, dark green leaves that exude a watery sap when broken, unlike other members of the milkweed clan that have opposite leaves and a milky sap. 

Butterfly-weed is aptly named as it attracts hordes of butterflies including Monarchs, Swallowtails, Fritillaries, and many others. Like other milkweeds, it is the larval host for our imperiled Monarch butterflies, as well as Queens, and Grey Hairstreaks. The caterpillars of Monarch and Queen butterflies have evolved to metabolize glyco-cardiosides, the toxic chemicals found in milkweeds, making them unpalatable to predators. 

Butterfly-weed is native to sandy open soils, and is commonly found along our roadsides and fields in sunny sites. Its deep tuberous taproot helps the plant withstand droughts. While it is difficult to move mature plants, Butterfly-weed is easily grown from seed and seeds readily into gravel or sandy open soils. Aphids may sometimes be problematic but can be readily washed off with a hard spray of water; otherwise they have no serious diseases or pests.

Dried Butterfly-weed roots were used to treat pleurisy, and to relieve pain and breathing difficulties. The caterpillars mentioned above are absolutely dependent on these and other milkweeds – so plant loads of them for beauty and wildlife. 

Submitted by Betsy Washington, Northern Neck Chapter, Virginia Native Plant Society

Eastern Tiger Swallowtail butterfly visiting a Butterfly-weed in bloom. Photo by Betsy Washington.