Ministry of Agriculture, Food and Rural Affairs

Ontario Weeds: Whorled milkweed

Table of Contents

1. Name
2. Other Names
3. Family
4. General Description
   • Photos and Pictures
5. Stems and Roots
6. Flowers and Fruit
7. Habitat
8. Similar Species
9. Caution
10. Related Links

Name: Whorled milkweed, Asclepias verticillata L.,

Other Names: asclépiade verticillée

Family: Milkweed Family (Asclepiadaceae)

General Description: Perennial, reproducing only by seed.

Photos and Pictures

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

| Back to the Ontario Weeds Gallery |