How invasive species of plants spread
By Renee Sandelowsky and Helen Varekamp
Renee Sandelowsky and Helen Varekamp are Bayfield residents and local volunteers. They are writing a monthly series of articles about the benefits of planting native species of plants and the need to remove invasive species. This month (November 2026) they are writing about how invasive species of plants spread.
The key, to dealing with invasive species of plants, is to “ ... identify the pathways of introduction – the routes they take to spread to new areas – and cut them off ...” That is according to Canada’s Federal-Provincial-Territorial Biodiversity Working Group.
There are two main ways invasive plants spread in our environment:
Firstly, there are natural pathways, such as wind, water, and animals.
Secondly, there are human pathways.
– Horticultural Trade: Many invasive species are still being sold at some garden centres. Studies from around the globe, and confirmed by the Canadian Food Inspection Agency, indicate the ornamental/horticultural pathways are the primary routes for invasive plant introductions. Research plants before you buy them and request non-invasive or native plants at your local garden centre.
– Shipping: It is theorized that the Asian Long-horned Beetle and Emerald Ash Borer were accidental hitchhikers in wooden shipping pallets.
– Recreation: Hiking, biking and boating can spread seeds, as could moving firewood. Clean off mud and plants from recreational vehicles (RVs), pets, hiking boots and any equipment before returning home. Stay on trails while hiking so as not to spread invasive species. Don’t move firewood. Burn where you buy!
– Agriculture, Forestry and Construction: Machinery can become shelters for invasive species and spread them.
– Travel and Tourism: Invasive species can hitchhike on vehicles, boats, clothing, luggage, or pets, or could be intentionally brought in from other areas.
– Pond and Aquarium Trade: Some species escape, or are intentionally disposed of, into river systems. Never release aquarium or pond plants or fish into the wild. Return them to the store or learn how to dispose of them properly.
– Landscaping: Dispose of your yard waste responsibly through municipal collection or designated bins. Never dump yard waste in parks, ravines or natural areas.
It’s important to note that a staggering 60 per cent of invasive plant introductions have been deliberate. A significant 83 per cent of these invasive plants, once imported for horticultural use, remain commercially available. Alarmingly, 97 per cent of these invasive species are expected to expand their range as climate change alters ecosystems. The current trends in horticulture not only perpetuate, but are set to accelerate, the spread of invasive species.
Prevention is the most cost-effective control for invasive plants. Consider supporting the Canadian Coalition for Invasive Plant Regulation. Their mandate is to regulate the sales of invasive plants at nurseries and garden centres. Also, have a good look at your own garden to determine if it is time to make some positive changes by replacing species that are now showing up on invasive plant lists.
– Renee Sandelowsky and Helen Varekamp are Bayfield residents and local volunteers. They are writing a monthly series of articles, about the need to remove and switch away from invasive plants in favour of native species of plants, for the Canadian Coalition for Invasive Plant Regulation.