For some years now, Toronto’s meadows, ravines, valleys and now, it seems, gardens have been increasingly blighted with a green pestilence: Dog-strangling vine (Vincetoxicum rossicum).
You can see it growing in eerie symmetry on the slopes by the Don Valley Parkway, to about a foot in height. Then, it starts to twine; with each other, up shrubs and and trees and hapless wildflowers.
About now (early June) it starts with its rather insignificant pinkish-brown flowers. Once fertilized, the plant makes narrow pods that will later release milkweed-like puffy airborne seeds. It is a cousin of the common milkweed.
What’s so insidious is that it’s almost unstoppable. It reproduces by seed; many seeds per plant. It reproduces by runners under the soil. Trying to yank it up through weeding can cause breaks in the root system – and each break can encourage a new growth top. It can cover large areas in a scarily short time.
If you find dog-strangling vine in your garden, don’t let it get a toe-hold. The best, most earth-friendly thing to do is to cut the stem(s) off at, or just below, the soil level. Do not let it reach the fruiting stage; do not compost the roots or seed pods. If you see it in a neighbour’s garden, give them a word to the wise.
This one is worse than the Lythrum scare of a few years ago. At least Lythrum, AKA purple loosestrife, has redeeming qualities – for one, it’s pretty. But both plants are choking out our native wildflowers. And dog-strangling vine can grow anywhere, sun, shade, cracks in the sidewalk; anywhere; not only in marshlands.
Get worried. Get informed. Please do your best to do something about it.