Questions and Answers

Invasive plants are plant species that can be harmful when introduced to new environments. These plants can reproduce quickly and thrive in different habitats.

Invasive plants can grow in natural areas (forests, grasslands and wetlands), managed areas (cultivated fields, gardens, lawns and pastures), and areas where the soil and vegetation have been disturbed (ditches, rights of way and roadsides).

Why are invasive plants a problem?

A plant that looks harmless can invade agricultural and natural areas, causing serious damage to Canada's economy and environment. Invasive plants in crops and pastures cost an estimated $2.2 billion each year by reducing crop yields and quality, and increasing costs of weed control and harvesting.

In natural areas, invasive plants can negatively affect ecosystems. They create an imbalance in nature by competing for the same resources that native species need to survive.

The resulting changed landscapes can impact recreational activities and tourism, as well as aesthetic and property values. Human health can also be affected as some invasive plants are toxic, or cause skin reactions or allergies. In some cases, animal health may also be affected.

How do invasive plants spread?

Some invasive plants are brought into Canada for agricultural, horticultural or medicinal purposes. Others are introduced when people are not aware a plant is invasive and they introduce it to a new area.

Invasive plants and their seeds can be dispersed naturally by animals, birds, water and wind. Humans can unintentionally move them with soil or as contaminants in forage, grain, seed and other plant products. They can also be carried on clothing, equipment and vehicles, including cars, farm machinery and railway cars.

What is being done to protect Canada from invasive plants?

Federal, provincial and municipal governments are working to stop the spread of invasive plants.

As Canada's plant protection agency, the Canadian Food Inspection Agency (CFIA) monitors plants around the world and the potential impacts on plant resources if certain invasive plants became established here.

The CFIA regulates various invasive plant species under the Plant Protection Act and Seeds Act. When an invasive plant species is regulated by the CFIA, there are restrictions on the import, sale and movement of these species into and within Canada.

What invasive plants are currently regulated by the CFIA?

Currently, the following plants are regulated by the CFIA under the Plant Protection Act:

  • Broomrape (Orobanche spp.)
  • Dodder (Cuscuta spp.)
  • Witchweed (Striga spp.)
  • Woolly cup grass (Eriochloa villosa)

How can I help?

Everyone can play a part in protecting Canada's environment from invasive plants. These are some of the steps you can take to help stop the spread of invasive plants in Canada:

  • Be informed about invasive plants.
  • Avoid planting invasive plants in your garden.
  • Ensure machinery, vehicles and tools are free of soil and plant parts before moving them from one area to another.
  • Avoid moving seeds and plant material on your clothes, footwear, camping gear and vehicles.
  • Declare all plants and related products when returning to Canada.
  • Use clean, high-quality seed that is certified if possible.
  • Use clean grain, hay and straw.
  • Maintain healthy and diverse pastures.
  • Contact your local CFIA office if you suspect you have found an invasive plant. The CFIA will follow up and determine if further action is needed.
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