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Invasive Plant Species Targeted

A group of volunteers pull garlic mustard

For several years many volunteers have assisted the Couchiching Conservancy in the battle to control the spread of invasive plant species.
The two species that are most often dealt with are garlic mustard and dog-strangling vine, both of which are true threats to the well-being and biodiversity of several of our properties. Unfortunately, there are other species which are also making steady progress in establishing themselves in the area, such as Japanese knotweed and phragmites reed.

Garlic mustard loves to grow in mature hardwood forests, and their colonies tend to crowd out native species such as trillium, violet, jack-in-the-pulpit and others. In addition to the crowding of surface vegetation, garlic mustard also destroys some types of soil fungus in order to limit competitive growth. But when this soil fungus disappears, the tiny rootlets of huge trees can no longer obtain nutrients and elements once provided by the fungus. The result is a nutrient-stressed tree that becomes vulnerable to insect damage and disease.

Dog-strangling vine has established itself in the open limestone areas, perhaps better known to us as alvar habitat. Not content to just populate the edges of clearings, dog-strangling vine grows in thick stands of intertwined stems, totally shading any and all other plant species. Spreading its seeds by wind (much like milkweeds) it moves rapidly across the countryside; and being a perennial it stays rooted for many years. As well, monarch butterflies are tricked into laying eggs on this plant, which cannot provide proper nutrition to the developing caterpillars.

Garlic mustard is best controlled by pulling up the plant before it can produce flowers and seeds, an action done by volunteers at Church Woods (Shanty Bay) and Elliott Woods (near Craighurst) for many of the past years.  Once the seeds fall to the ground they can lay dormant for 1 – 15 years, sprouting at any time; this is called the seed bank, and we are trying to deplete the existing seed bank while not allowing any ‘deposits’ of new seeds.

Controlling dog-strangling vine is a different story. Picking the unripe pods certainly slows down the spread, but if only a couple of plants are missed then hundreds of seeds are dispersed.  Other methods of control (pulling, digging) have proven unsuccessful in having any effect on their populations. Which leaves us with chemical application, or spraying of a herbicide. This was done in very controlled situations last year and the results have proven hopeful. Spraying is not done by volunteers but by trained and licensed professionals.

Training sessions have been held, and more will be provided this spring, to make our volunteers aware of invasive plant species, how to identify them, how to map and monitor their presence and how to control their spread. To that end a new position has been created within the Couchiching Conservancy, specifically to work with volunteers and control invasive plant species on our properties.  Contact David Hawke for more information  steward(at)  or (705) 326-4643