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Invasive Species

1.1 Controlling and Disposing of Non-native and Invasive Species

The most efficient approach to controlling invasive plant species is to focus on removing satellite populations or limiting plants before they start to dominate large areas. This reduces their likelihood of spreading to other areas, and mitigates their overall impacts on Ecological Integrity. If left unmanaged, most invasive species will outgrow other species and displace the native plant community of an area. There are some simple steps to eradicating or managing invasive plant species, including removing the entire plant (e.g. digging or pulling), cutting above ground vegetation, tarping the area, or using chemical control.

If possible, removing the entire plant including both above ground vegetation and the plant’s root network can be very effective. This can be done by digging the entire plant from the ground, or in some cases, pulling the plant out of the ground as long as the root system comes with it. This approach can be labour intensive, but also removes the most plant material from the site. Some invasive species have large root systems and will quickly re-sprout if the roots are not completely removed. If the plant has been established for a long time and has an extensive root system, it may be difficult to completely remove on the first attempt. However, if the plant re-sprouts, then the location of the missed root system will be revealed and this area should be targeted for the next removal. This process may need to be repeated many times before eradication of the invasive species is achieved. Depending on the time of year and/or the plant species, care should be taken to not leave any plant material or seed on site after removal. Some invasive plants can regrow from a single piece of stem or root, therefore any vegetation must be disposed of appropriately (see Disposal). 

Cutting above ground vegetation can be effective at controlling invasive plant species and limiting their growth, if done at a regular interval throughout the growing season (e.g. once a month). Continual cutting will eventually weaken the root system, decreasing the plant’s ability to regrow. Some invasive plants can regrow from a single piece of cut stem or root, therefore any cut vegetation must be disposed of appropriately (see Disposal). Cutting is often used to control invasive plants prior to chemical control, and facilitates the most effective use of herbicide.

In some areas, using a heavy tarpaulin to cover an area infested with invasive species can effectively kill the plants. Covering plants with a tarpaulin will limit the amount of sunlight and moisture available, thereby preventing growth. By using a dark coloured material to cover the plants in sun exposed areas, the microclimate underneath will become so warm that the effect will be similar to cooking the plants. Edges of the tarpaulin should be weighted down to prevent light from entering underneath, and to prevent the tarpaulin from blowing away. Tarping is typically most effective when started in the spring, and is not recommended in low-light areas. The tarpaulin may need to be in place for more than one growing season for effective control, depending on the persistence of the invasive species. For some invasive species, plants will need to be dug or cut beforehand, so that the tarpaulin can lay close to the ground. An area larger than the infestation should be covered by the tarpaulin, as some invasive species will send out shoots laterally to find light. This method can be labour intensive, as the tarpaulin needs to be monitored for plants growing through or from the edges of the tarpaulin. As tarping kills all plant life in the area that it covers, replanting with native vegetation once control measures are complete may be required.

Chemical Control
In some circumstances controlling and eradicating persistent invasive plant species may require the use of herbicides. Cottagers are not permitted to use herbicides unless authorized by the Ministry. In situations where herbicides will be effective, some preliminary work may be required (e.g. cutting of vegetation). If you think that chemical control is required to manage an invasive species, or if the species profile indicates that herbicide may be the most effective treatment, contact Ontario Parks for further information at or 705-645-7436.

Great care must be taken when disposing of invasive plants because some species can regenerate and/or colonize new areas from a single piece of rhizome, root stock, seed, or above ground vegetation.

Disposal of all invasive species should be done by:

  • Placing all plant material in heavy duty, construction grade black garbage bags. Seal the bags tightly, and cover any holes in the bag (e.g. with tape). When bagging root material, minimize the amount of soil being disposed of.
  • Garbage bags with plant material may be left in direct sunlight for a week or longer, to help kill plant material.
  • Care should be taken to not rip or otherwise put holes in the garbage bags so that the plant material remains contained.
  • Garbage bags with invasive species should be placed in the designated garbage receptacles, or otherwise disposed of in landfill. Unfortunately, because invasive species can be spread during the disposal process and living plant material may survive, they cannot be composted.