Ville de Montréal

Controlling invasive alien plant species to protect native plants

Last updated November 24, 2025

Reading time: 2 min

The city is working to control invasive alien plant species (IAPS) and reduce their impact on biodiversity. Here is some information about how to recognize these plants and avoid spreading them.

An invasive alien plant is a plant that is not native to Québec. Once introduced, it establishes itself and spreads in such a way that it threatens native vegetation.

The main invasive plant species

Learn how to recognize invasive plant species, and how to prevent and control them. You can find information on the website of the Ministère de l’Environnement, de la Lutte contre les changements climatiques, de la Faune (in French).

Work to combat IAPS

Work is underway in certain areas to control invasive alien plant species and reduce their impact on biodiversity. Here is a list of the work currently underway:

Parc-nature du Cap Saint-Jacques – Embouchure sector

Target species: Vinca minor (periwinkle)
Description of work: Tarpaulins installed over colonies and annual monitoring to maintain the tarps and remove regrowth. The tarps will remain in place for two years.

Parc-nature de bois-de-Liesse – Champs sector

Target species: Buckthorn
Description of work: Pilot project to control buckthorn using a specific cutting technique

Parc-nature du Bois-de-Saraguay – Sentier Polo sector

Target species: Japanese knotweed
Description of work: Tarps installed over colonies and annual monitoring to maintain the tarps and control regrowth. The tarps will remain in place for at least six years to control this species.

Parc-nature de la Pointe-aux-Prairies – Bois-de-la-Réparation sector

Target species: Buckthorn
Description of work: Manual removal of plants, cutting and encapsulation of large specimens
Target species: Garlic mustard
Description of work: Manual removal of plants between April and June
Target species: Common reed
Description of work: Plant bending

Parc-nature de la Pointe-aux-Prairies – River and Marais sectors

Target species: Japanese knotweed
Description of work: Tarps installed over colonies and annual monitoring to maintain tarps and control regrowth. Tarps will be kept in place for at least six years to control this species.

Parc Frédéric-Back– Boisé and Plaine sectors

Target species: Common reed
Description of work: Installation of tarps over colonies and annual monitoring for tarp maintenance and control of regrowth around the perimeter. The tarps will be kept in place for 2 to 3 years to control the species. The work will be completed by seeding and planting native plants in the area.

Mount Royal Park – Flanc Sud and Sommet sectors

Target species: Buckthorn and alder buckthorn
Description of work: Manual removal of plants, cutting and encapsulation of large specimens
Target species: Norway maple
Description of work: Manual removal of young plants, cutting of large specimens
Target species: Virginia creeper
Description of work: Covering of plants with tarps.

Work to control invasive plant species is accompanied by seeding and planting native plants in the same area.

Get involved

Check your yard

Check for IAPS and replace them with native plants.

What happens to the removed invasive plants?

You may dispose of these plants in your organic waste bins. They are destroyed through the composting process in our municipal facilities.
Do not dispose of them in your garden compost, as they will not be fully eliminated and may spread.
When city employees or volunteers remove large amounts of invasive plants from parks or community gardens, they are discarded in garbage bins.