Butterfly Milkweed (Asclepias Tuberosa L.)

Butterfly Milkweed (Asclepias Tuberosa L.)

Other common names:

• Pleurisy Root
• Butterfly Weed
• Yellow Milkweed
• Orange Swallowwort
• Orangeroot
• Whiteroot
• Indian Posy
• Windroot
• Canada Tuber
• Canada Flux
• Chigger Flower

Asclepias: from the name of the Greek god of healing and medicine

Tuberosa: meaning “tuberous,” referring to the tuberous root

Milkweed Family: Asclepiadaceae

Found throughout the tallgrass biome in dry, open areas, usually in prairies or prairie relicts. Occasionally it is found along old country roads or old or abandoned roads or railroad rights-of-way. Flowers from June to September.

The stout, simple or terminally branched stems are generally clumped and may be up to 2 ½ feet high. Rough-pointed leaves up to 6 inches long alternate along the stem. The typical milkweed milky sap is lacking; instead, a watery juice exudes from the cut stem.

The flowers are normally bright orange but occasionally are yellow. Many individual flowers are in a head.

            The flowers attract insects, but like the flowers of other milkweed plants, they are designed to favor larger flying pollinators and to prevent crawling insects from getting to the nectar. As with other milkweeds, only a few of the numerous flowers get pollinated, so ordinarily a plant has only one or two pods. This is due to a complex pollinating mechanism where the pollen sacs are attached to a structure located in the slit between the anthers. This pollinium, which sticks to the pollinating insect, must be pulled free and carried to another flower. Many insects lack the strength to pull this structure or themselves free and are found dead on the flower head.

            The spindle-shaped pods, 3 to 5 inches long, contain many seeds. Each seed has a silky plume to aid in its dispersal.

            This species reproduces by seed and by rootstock. It is easily established in gardens or in restored prairies from seed, but transplanting is difficult because the root is stout and deep.

At one time this root was considered to be a cure for pleurisy, hence, the name pleurisy root. Early doctors listed pleurisy root as a subtonic, diaphoretic, alternative, expectorant, diuretic, laxative, escharotic, carminative, astringent, ant rheumatic and ant syphilitic.

            The root is enlarged. This gave rise to the last part of the scientific name.

            Butterfly milkweed is one of the most striking species of the tallgrass biome. The bright color may attract insects, including butterflies, hence, its common name.

            At least 16 species of milkweed occur in the heart of the tallgrass prairie. Some provide an index of prairie quality; none are showy as the butterfly milkweed.

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