What is a Butterfly Weed?

Butterfly weed (Asclepias tuberosa) is an herbaceous perennial species of milkweed native to North America. It is often found growing along roadsides and in naturalized areas throughout the eastern United States. The plant is known by many other names including Canada root, chigger flower, fluxroot, windroot and Indian paintbrush. The name “butterfly weed” derives from the plant's attractiveness to butterflies, which flock to the colorful, nectar-filled flowers in spring.

Eventually growing up to 30 inches (76.2 centimeters) in height and 24 inches (60.96 centimeters) in width, slow-growing butterfly weed may take up to four years to reach its mature size. The plant's alternate, deep green leaves reach 2 to 6 inches (5.08 centimeters to 15.24 centimeters) in length, and typically lack any significant fall color. Unlike all other milkweeds, the plant's stems do not produce a milky sap when broken, and it is sometimes referred to as the “milkless” milkweed. The showiest of all milkweeds, butterfly weed produces vivid yellow, orange or red flowers that appear in the spring and summer. The blossoms appear in clusters of 20 or more, known as umbels.

A long, fibrous taproot allows butterfly weed to resist drought better than other milkweeds, and it has adapted well to dry conditions. Once established, an individual plant may survive for decades, as long as conditions remain favorable for growth. The plant prefers dry, sandy or gravelly, well-drained soil and full sunlight. It can tolerate light shade if necessary, but may take even longer to reach its full size. Although easily propagated from seeds or cuttings, the weed does not transplant well because of its long taproot.

Like all milkweed species, butterfly weed contains cardiac glycosides, organic compounds that are extremely toxic to mammals and many insects. Boiling water renders most types of milkweed safe for consumption, but the leaves, stems and flowers of Asclepias tuberosa should not be consumed, even after boiling. Despite the toxicity of the plant's above-ground parts, Native Americans and many pioneer doctors found the taproot medicinally beneficial. They used teas and infusions made with the root to treat pulmonary conditions such as pleurisy, asthma and bronchitis. This is likely the origin of another of the plant's common names, pleurisy root.

Butterfly weed root was also used externally for medicinal purposes. Poultices made with the pulverized root were applied to skin ailments such as cuts and bruises, and to arthritic ailments. The Sioux Indians boiled the roots for food, and often served the plant's seed pods with buffalo meat. Other traditional uses include making dye from the flowers, often used by Native Americans to dye baskets, and making fiber and bowstrings from the plant's stalks.