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The Battle Against Invasive Plants Continues!

Volunteers picking Garlic Mustard
Alexander Hope-Smith Property Management Team with 2013 Summer Students Nick and Rianna

Unfortunately, several of our properties have seen the arrival of unwanted plant species. Yuck! The undesirables include garlic mustard, dog-strangling vine (aka DSV) and phragmites, as well as a list of species with lesser yet still negative effects (including periwinkle, buckthorns and yellow iris).

The volunteers who keep an eye on our properties have made great effort to stop the continued spread of these plants, particularly garlic mustard and DSV. The mustard has established itself heavily within the hardwood forests of Elliott Woods and Church Woods, and if left unchecked could become so thick that mature maple and oak trees may become weakened from nutrient loss. But due to a constant pressure applied by volunteers, these plants are being removed before any more new seeds can be added to the seedbank.

Over the past year we have set up monitoring plots where we measure the density and size of each patch of invaders, and already there is an indication that we have made progress in controlling and reducing the spread of this plant.

On the open limestone areas known as the Carden Plain, DSV has swept in on the winds (the seeds are very much like milkweed seeds) and rooted itself with amazing rapidity. Pod picking has been undertaken to lessen the spread of seeds, but this is a daunting task. In partnership with the Nature Conservancy of Canada, a chemical spray program has been undertaken to thwart DSV. The decision to use chemicals was a hard one to make, but until a biological control (insects that eat the plant) is found, this method is working to thin the ranks of this tenacious species.

Phragmites (better known as common reed) has shown up in a few wetlands and is presenting a challenge on how to deal with it. As members of the Great Lakes Phragmites network, we are looking at ways to squash this plant before it spreads to an uncontrollable level.

And our efforts have been noticed, as follow-up inquiries to Dave Hawke’s presentation at the recent Ontario Invasive Plant Council’s workshop have come from the University of Toronto, University of Guelph and Ontario Nature. Looks like what our volunteers are accomplishing is more than just cleaner local forests, we are setting the standard for controlling invasive species!

By Dave Hawke, Stewardship Program Manager