Asclepiadaceae - milkweed family
 

WeedsPoisonous PlantsHay Fever
Gerald A. Mulligan (Agriculture Canada, Ottawa, retired)
Asclepias syriaca L., common milkweed, asclépiade commune
Perennial with a white, sticky juice, spreading by seeds and by thick fleshy roots; allogamous; 2 to 4 feet (6 to 12 dm.) high; flowers usually purplish; pastures, grain fields, cultivated fields, roadsides, fencerows, and waste places in settled areas of the eastern half of North America. A common food plant for the larvae of the monarch butterfly. Some poisoning and death of sheep and cattle has been reported. However, livestock usually avoid eating this plant.

Cynanchum louiseae Kartesz & Gandhi (= Vincetoxicum nigrum (L.) Moench), black dog-strangling vine, dompte-venin noir
Perennial, spreading by seeds; twinning stems 3 to 12 feet (10 to 40 dm) high; flowers dark purple or blackish; southern Quebec and Ontario; in gardens, hedgerows, fencerows, old fields, thickets, open forests and disturbed areas; introduced from western Europe. Probably toxic to livestock and humans.
Text and photos of black dog-strangling vine by Stephen J. Darbyshire

Cynanchum rossicum (Kleopow) Borhidi (= Vincetoxicum rossicum (Kleopow) Barbar), dog-strangling vine, dompte-venin de Russie
Perennial, spreading by seeds; twinning stems 3 to 9 feet (10 to 30 dm) high; flowers pinkish, maroon, reddish brown or very rarely white; southern Quebec and Ontario; in gardens, hedgerows, fencerows, old fields, thickets, open forests and disturbed areas; introduced from eastern Europe. Toxic to livestock and probably humans.
Text and photos of dog-strangling vine by Stephen J. Darbyshire

Click on a photo to view an enlarged image.
Weed Name Photo Weed Name Photo
common milkweed, asclépiade commune
(flowers)
common milkweed, asclépiade commune
(F&M)
common milkweed, asclépiade commune
(flowers)
common milkweed, asclépiade commune
(in fruit)
common milkweed, asclépiade commune
(plants with fruit open)
common milkweed, asclépiade commune
(open fruit with brown seeds attached to tufts of hair)
common milkweed, asclépiade commune
(in winter)
common milkweed, asclépiade commune
(shoot from fleshy underground root)
common milkweed, asclépiade commune
(seedling)
black dog-strangling vine, dompte-venin noir
(fruiting plants)
black dog-strangling vine, dompte-venin noir
(flowers)
dog-strangling vine, dompte-venin de Russie
(flowering plants)
dog-strangling vine, dompte-venin de Russie
(fruiting plants)
dog-strangling vine, dompte-venin de Russie
(flowers)
dog-strangling vine, dompte-venin de Russie
(flower colour variation)
dog-strangling vine, dompte-venin de Russie
(fruits)
dog-strangling vine, dompte-venin de Russie
(young plants)
dog-strangling vine, dompte-venin de Russie
(seedlings)