Ohio Perennial and Biennial Weed Guide

Family:

Milkweed Family (Asclepiadaceae)

Other Names:

archangel, butterfly weed, Canada root, chigger flower, fluxroot, fly catcher, Indian paint, Indian plume, Indian posy, orange milkweed, orange root, pleurisy root, silkweed, swallowwort, white root, wind root, yellow milkweed.

Origin and Distribution:

Butterfly milkweed is a native of North America. Currently, its range extends throughout the eastern U.S., around the Great Lakes, and along the Mississippi River. It occurs throughout Ohio and is especially abundant in east-central and southern counties. The plant's natural distribution includes dry fields, pastures, prairies, roadsides, waste places, and other open habitats. Also, it is sometimes available for purchase as a native wildflower for planting in home gardens. Butterfly milkweed prefers dry sandy soils and it grows best in full sun to light shade.

Plant Description:

Butterfly milkweed is a perennial member of the Milkweed Family that looks similar to other family members except for its showy orange flowers and watery rather than milky sap. It has upright stems that are hairy, leafy, and branched near the top of the plant. Reproduction is by seeds.

• Root System:

  The large root crown consists of a brittle taproot extending deep into the soil and massive tuberous roots.

• Seedlings and Shoots:

  Young stems appear to shorten during growth resulting in below-ground burial of the leaf stalks (petioles) attached to the first two seed leaves (cotyledons) as well as buds in underground axils.

• Stems:

  Stems emerge either alone or in clusters from a single root crown. They generally are upright, rough-hairy, and 1 to 3 feet tall. Stems are undivided at the base, branched at the apex, and usually very leafy.

• Leaves:

  Leaves are scattered about the stem in pairs such that most of the time they are alternate (1 leaf per node) but sometimes they appear opposite (2 leaves per node). Leaves are 1 1/2 to 6 inches long, narrow, oval, and taper to a point at the tip. Leaf shapes vary considerably. The under sides of leaves are especially hairy while hairs are sometimes found on the upper sides. Leaves attach to stems by way of short petioles that are covered with soft, short hairs.

• Flowers:

  Flowers consist of 5 curved-back petals that are bright orange to reddish-orange or yellowish-orange. Individual flowers are 3/8 inch wide and they are arranged in 2-inch-wide terminal clusters.

• Fruits and Seeds:

  Seed pods are 2 to 4 inches long, upright, narrow, spindle-shaped, and hairy. Each pod splits when mature releasing numerous flat, brown seeds. Seeds are approximately 1/4 inch long and have tufts of silky hairs at one end.

Similar Species:

Common milkweed (Asclepias syriaca) is similar in appearance to butterfly milkweed except it has pinkish flowers and its sap is milky rather than watery.

Biology:

Flowering occurs between mid-June to early September. A characteristic of this species is the long taproot that allows it to survive dry conditions.

Toxicity:

Most parts of the plant contain toxic compounds that can be poisonous to humans and other animals if consumed in large enough quantities. However, since butterfly milkweed is so distasteful, most livestock and other animals will not eat it. In humans, the sap can produce contact dermatitis.

Facts and Folklore:

• The plant got its common name because of its attractiveness to a wide variety of butterflies such as monarchs, swallowtails, sulphurs, coppers, hairstreaks and fritillaries.

• Another common name given this plant is 'pleurisy root', because the root has medicinal uses as an emetic and diuretic and was used to treat pleurisy.

• Native Americans found many uses for butterfly milkweed. The plant's fibers were used in textiles and bowstrings, a red dye could be extracted for basket and textile decoration, and they had many medicinal uses for the roots.