Ontario Wildflowers website

White Swallowwort
Cynanchum vincetoxicum

Other common names: Dog Strangling Vine, Poison-rope Swallowwort

Other scientific names: Vincetoxicum album, Vincetoxicum hirundinaria, Vincetoxicum officinale

French names: Dompté-venin

Family: Dogbane Family (Apocynaceae), (Milkweed Family (Asclepiadaceae))

Group: Swallowworts

Distinctive features: Opposite leaves on a vine, milkweed-like seed pods and seeds.

Similar species:
  •   Black Swallowwort (Cynanchum louiseae)

  •   Pale Swallowwort (Cynanchum rossicum)


Flowers: Summer;  White;  5 parts (petals);  5-petals, white, 1/4" wide, late spring & summer.

Leaves: Opposite/Whorled, Entire;  Opposite pairs, sometimes in a whorl, egg-shaped.

Height: Vine, 2-6 feet long.

Stem: Vine.

Fruit/Seeds: In a pod, closely resembling those of milkweed. but smaller.

Habitat: Fields and Open Areas;  Open areas, forest edges.

Native/Non-native: Non-native

Status: Uncommon.

Notes: This is a highly invasive alien plant, that will aggressively take over an area once it gets a chance. Pull it up before it gets a foothold.

See Also:
  •   Swallow-wort: Monarch Menace, from The Monday Garden, by Sue Sweeney


Photographs: 39 photographs available, of which 6 are featured on this page. SCROLL DOWN FOR PHOTOGRAPHS.

Range Map is at the bottom of the page

White Swallowwort (Cynanchum vincetoxicum)

White flowers, about 1/4" across.

White Swallowwort (Cynanchum vincetoxicum)

White Swallowwort (Cynanchum vincetoxicum)

Closeup of a flower.

White Swallowwort (Cynanchum vincetoxicum)

The vines climb above other vegetation and cover it.

White Swallowwort (Cynanchum vincetoxicum)

A pair of the egg-shaped leaves.

White Swallowwort (Cynanchum vincetoxicum)

Sometimes the leaves are narrower.


Range map for White Swallowwort (Cynanchum vincetoxicum)

PLEASE NOTE: A coloured Province or State means this species occurs somewhere in that Province/State.
The entire Province/State is coloured, regardless of where in that Province/State it occurs.

(Range map provided courtesy of the USDA website and is displayed here in accordance with their Policies)