ND Noxious & Troublesome Weeds
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Common
and Showy Milkweed (Asclepias syriaca L. and A. speciosa Torr.) |
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Growth form: Both are native perennials,
that generally grow from 3 to 5 feet tall. Leaves are opposite, oval-shaped,
and 4 to 8 inches long with prominent veins. Common milkweed flowers are light pink to white contained
in ball-like clusters. Showy milkweed flowers are in umbels at the top
of the plant and generally purplish-pink and more prominent than common
milkweed.
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Both species are favored by butterflies.
Common milkweed is a major source of food for the monarch butterfly
larvae (white, black, and yellow strips). Showy milkweed is a source
of nectar for many insects including the swallow tail butterfly. |
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The
stems are hollow, pubescent, and very stiff. All plant parts contain
a milky white latex. The plants spread both by large vertical and horizontal
roots and by seed which are spread by wind on tufts of hairs. 