Battle of the Dog-Strangling Vine

One of the up-front tasks in creating a farm involves reclaiming the land, and we plan to blog about the many experiences that fall under this topic. There are about 3 acres of wooded lot on the north side of the property and along its edges we noticed Dog Strangling Vine (Cynanchum rossicum, aka swallowwort) growing in a number of places. While it does not actually strangle dogs, it is one of Ontario’s most unwanted invasive species. The vine can attach to small trees and plants and climb up to 2 m high and “strangle” native vegetation if allowed to flourish.

Dog-strangling vine is a member of the milkweed family, but it can pose a risk to the Monarch butterfly, which lays its eggs exclusively on some native milkweed species. This vine, however, does not make the “safe” list. Monarch caterpillars hatched on dog-strangling vine plants die because the vines don't provide the food the larvae actually require. (We do have plans to start a Monarch butterfly nursery using the proper type of milkweed. Details to follow in a future post.)

The vine must ultimately be dug out by hand to prevent its roots from spreading, and then properly disposed of by allowing it to rot in black plastic bags. Sources note that it should never be added to green compost waste. A first step is to simply hack it back, and a scythe is a handy implement to employ in this battle. The scythe looks and feels like an “old-time” implement, and proper use of it involves long, sweeping strokes that have an almost balletic quality to them.

It is wise to be as covered up as much as possible while engaging in this battle, preferably in long pants and a long sleeved shirt. Poison ivy is also a native species, and ticks have become a problem across Ontario, so it’s smart to conduct a careful spot-check afterwards to ensure nothing unwanted has hitched a ride on you out of the woods.

Sources: Nature Conservancy of Canada

Nottawasaga Valley Conservation Authority

Ontario’s Invading Species Awareness Program