Ontario Weeds: Whorled milkweed
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Excerpt from Publication 505, Ontario Weeds,
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Table of Contents
- Name
- Other Names
- Family
- General Description
- Stems and Roots
- Flowers and Fruit
- Habitat
- Similar Species
- Caution
- Related Links
Name: Whorled milkweed, Asclepias
verticillata L.,
Other Names: asclépiade verticillée
Family: Milkweed Family (Asclepiadaceae)
General Description: Perennial, reproducing
only by seed.
Stems & Roots: Stems erect, 20-90cm
(8-36in.) high, sparingly branched in the upper part, slender, 1
or several from a cluster of fibrous roots; bases of old stems often
persisting; leaves very narrow, in whorls of 3 to 6 at each node
of the stem; flowers and seedpods similar to Common
milkweed but the clusters are smaller and fewer-flowered.
Flowers & Fruit: Flowers smaller
and greenish, and the seedpods smaller, thinner, and lacking the
soft, warty bumps. Flowers from July to September.
Habitat: Whorled milkweed occurs in
dry open areas in pastures, around woods, and along roadsides in
the western portion of southern Ontario.
Similar Species: It is distinguished by
its slender, erect stems with whorls of 3 - 6 narrow leaves, its
flowers in umbels and all plant parts containing a milky juice.
Caution: It is poisonous to livestock.
Related Links
... on general Weed
topics
... on weed identification, order OMAFRA
Publication 505: Ontario Weeds
... on weed control, order OMAFRA
Publication 75: Guide To Weed Control
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