Ontario Weeds: Dog-strangling
vine
Table of Contents
- Name
- Other Names
- Family
- General Description
- Stems and Roots
- Flowers and Fruit
- Habitat
- Similar Species
- Caution
- Related Links
Name: Dog-strangling vine, Vincetoxicum
nigrum (L.) Moench,
Other Names: cynanque noir, Black swallow-wort,
Cynanchum nigrum (L.) Pers.
Family: Milkweed Family (Asclepiadaceae)
General Description: Perennial, reproducing
by seed and by spreading underground rhizomes.
Photos and Pictures
Dog-strangling vine (A - plant; B - pairs of leaves
and pairs of spreading seedpods).
Dog-strangling vine. A. Base of plant with
flowering branch. B. Twining branches with 2 open seedpods.
Stems & Roots: Stem vine-like,
herbaceous or with woody base which overwinters successfully in
Ontario, 1-2m (3-6½ft) long, scrambling or climbing over
fences and other vegetation and often forming impenetrable masses.
Leaves opposite (2 per node), oval to oblong with rounded bases
and abruptly pointed tips.
Flowers & Fruit: Flowers purple-brown
to dark purple, small, in small umbel-like clusters at tips of stems
and upper branches; seedpods slender, 4-6cm (1½ -2¼in.)
long, broadest near the base and long-tapered to a slender tip,
opening along one side and releasing many, small, flat, brownish
seeds with long, white, silky parachutes. All parts of the plants
may contain small quantities of white, milky juice. Flowers from
late June until autumn.
Habitat: Dog-strangling vine occurs
in several localities in southern Ontario, growing in ravines, hillsides,
waste areas, fence lines and hedges.
Similar Species: It is distinguished by
its perennial vine habit, opposite leaves, purplish flowers, slender
seedpods with parachute seeds, and somewhat milky juice.
Caution: This plant should be regarded
with suspicion as it was included in early books on poisonous plants.
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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