Common Milkweed

Asclepias syriaca
Apocynaceae (dogbanes); formerly Asclepiadaceae (milkweeds)

A sturdy, upright plant with broad leaves, milky sap, and clusters of pink or lilac flowers. Blooms May through August. Flowers are pink to lilac, very fragrant, borne in clusters terminally and along the stems, arising from leaf axils. Leaves are broadly elliptical, rounded at the base, to 6 inches long, with find hairs underneath, on distinct leaf stalks. Fruit are large seedpods (follicles), elongated and covered with slender warty projections. When dry, these split to release hundreds of seeds, each attached to a “parachute” of white, silky, flossy hairs that can carry them on the wind.

Similar species: There are 17 species in the genus Asclepias in Missouri. The one most similar is purple milkweed, whose flowers are darker and more purplish and whose pods lack slender warty projections.

Height: usually to about 3–4 feet, but can grow to 6 feet.
Habitat and conservation: 
Grows on upland fields, prairies, pastures, glades, roadsides, wasteland, edges of woods, and open, disturbed places. This is the most commonly seen milkweed, especially in abandoned fields and waste places, where it is an early colonizer of disturbed soil.
Distribution in Missouri: 
Common. This and other milkweeds are extremely important in conservation of the monarch butterfly, whose numbers are plummeting. Monarchs require milkweeds as larval host plants: Adult monarchs lay eggs on milkweeds, and their caterpillars eat the foliage. Herbicides, and an intolerance for weedy places, has reduced the number of milkweeds available for monarchs. You can help increase monarch numbers by growing this and other milkweeds.
Human connections: 
This plant has many uses. There have been attempts to make rubber out of the sap’s latex. The flossy seed hairs have been used as a stuffing. The dried pods are used in crafts and flower arrangements. The stem fibers can be used as a source for cordage, similar to flax or hemp.
Ecosystem connections: 
This is an important food plant for monarch butterflies, whose caterpillars eat the foliage, storing in their bodies milkweed’s toxic sap. This makes the monarch unpalatable to would-be predators. Other, less-celebrated insects eat milkweed and defend against predation the same way.
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