Invasives in The Islands: Dog Strangling Vine

By August 14, 2020 No Comments

Even TIWLT properties are not immune to the power and abundance of invasive species.

Dog strangling vine (DSV), also known as European swallow-wort, is one particular invasive plant which we have been actively attempting to eradicate on our properties. Dog strangling vine is a member of the milkweed family but unfortunately is not as benign as traditionally known milkweed. This is another plant which made its way to Canada from Europe via settlers.

DSV grows one to two metres tall with oval pointed-tip leaves. The plant grows upright until it can no longer support itself, then begins to grow in a vine-like pattern across the ground or onto neighbouring plants. Once attached to anything in close range, DSV lives up to its name by twisting and engulfing anything in its path including trees. Small pink or purple flowers appear in the spring and by mid-summer bean shaped seed pods appear releasing white feathery seeds in late summer.

Unfortunately for monarchs, dog strangling vine looks quite similar to milkweed and therefore some will lay their eggs on the DSV. This is a problem as monarch caterpillars can only eat certain native milkweed species. Consequentially, the caterpillars die shortly after hatching due to a lack of food. Dog strangling vine also threatens rare habitat in Ontario known as Alvars. Alvars are biological environments with little to no soil and exposed limestone where lichen, mosses, rare plants and animals live.

"Cynanchum rossicum" (Dog Strangling Vine) Photo Credit: Rob Routledge, Sault College, / CC BY (
Close up of the small pink flowers and pointed leaves characteristic of DSV. Photo Credit: Leslie J. Mehrhoff, University of Connecticut, / CC BY (

The best way to eradicate dog strangling vine is to identify it early, and dig out the plants. For those plants that cannot be dug out, at minimum cutting the flowers and seed pods off the plant can help prevent further spread. Once removed, plants should be placed in black garbage bags in the sun allowing the plants to rot, then disposed with garbage in the sealed garbage bags.

– By Emily Kutchaw, Agricultural Property Manager

To learn more about dog strangling vine or to get involved in invasive species removal with TIWLT, send us an email at

Anderson, Hayley. (2012). Invasive Dog-strangling Vine (Vincetoxicum rossicum) Best Management Practices in Ontario. Ontario Invasive Plant Council, Peterborough, ON.
Nature Conservancy Canada. (n.d.). Dog-strangling vine. Retrieved August 10, 2020, from
OFAH/OMNRF Invading Species Awareness Program. (2012). Dog-Strangling Vine. Retrieved from: