Flora Feature: Butterfly-weed

By Rachel Floyd, Center for Urban Habitats

Family: Apocynaceae
Genus: Asclepias
Species: tuberosa
Average Height: 24 inches
Bloom Time: June through August
Elevation Range: All elevations of the Piedmont
Geologic/Soil Associations: Prefers lean soils including rocky or sandy soils, but will tolerate clay if not kept too moist.
Soil Drainage Regimes: Xeric, Dry-mesic, and Mesic. Well drained.
Aspect: Full sun is prefered. If other conditions are met, will grow in part shade.
Habitat Associations: Dry woodland clearings, meadows, abandoned pasture and agricultural fields, roadsides, prairies in powerline right-of-ways, hot and dry landscape restorations in urban spaces and natural area preserves.
Flora Associations: Butterfly-weed collaborates with little bluestem (Schizachyrium scoparium), Small’s ragwort (Packera smallii), broomsedge bluestem (Andropogon virginicus), common yarrow (Achillea borealis), purple lovegrass (Eragrostis spectabilis), Carolina rose (Rosa carolina), and many more to provide high quality habitat for hundreds of animals in the Piedmont.
Fauna Associations: The partnership between plants in this genus and the boldly patterned Monarch butterfly is well known. The Monarch is a tropical species that has greatly expanded its range by relying on the widespread temperate milkweeds as both a food source and as a means of protection against predation.  Monarch caterpillars grow fat on the leaves while concentrating toxic glucosides from them in their skin. Adult butterflies of many species are drawn to sip from the bright orange flowers of butterfly-weed, thus giving it its common name. The abundant nectar also attracts digger (Melissodes ssp.), leaf-cutting (Megachile ssp.), and Halictid bees, as well as thread-waisted wasps (Ammophila ssp.) and ruby-throated hummingbirds (Archilochus colubris). The larvae of the unexpected cycnia moth (Cycnia inopinatus), the blackened milkweed beetle (Tetraopes melanurus), and the large and small milkweed bugs ( Oncopeltus fasciatus and Lygaeus kalmii) also eat the leaves of butterfly weed, obtaining nourishment and toxic armour from them.
Notes: The genus name references Asklepios, the Greek god of medicine.  Another common name for Asclepias tuberosa is pleurisy root. The tough root has a long history of use in the treatment of pleurisy and other pulmonary ailments.