A gap in the rules
Walk into almost any garden centre in Canada this summer and you can still buy plants that experts warn are actively harming local ecosystems. Species like purple loosestrife, English ivy, and Japanese knotweed remain on store shelves in many provinces, even though they're known to spread aggressively, crowd out native plants, and disrupt the food webs that local wildlife depend on.
That's the gap a growing number of Canadian cities are now trying to close. Several municipalities are drafting bylaws that would restrict or ban the sale of invasive plant species by garden centres and nurseries — a patchwork, city-by-city response to a problem advocates say needs a national fix.
Who's pushing for change
The Canadian Coalition for Invasive Plant Regulation has been leading the charge, arguing that Canada lacks two things most comparable countries already have: a federal horticulture body dedicated to tracking problem species, and a centralized invasive plant database that garden centres, landscapers, and homeowners could actually check before buying.
Right now, that job falls to a mix of provincial weed acts, regional conservation authorities, and municipal bylaws — a system advocates describe as inconsistent at best. A plant banned for sale in one province can often be found on shelves just across a provincial border.
Why it matters beyond the garden
Invasive plants don't stay in the yard they were planted in. Seeds spread by wind, water, birds, and even soil clinging to garden tools, letting ornamental plants escape into parks, ravines, and waterways. Once established, many are extremely difficult and expensive to remove, and they can outcompete native plants that local insects, birds, and pollinators rely on for food and habitat.
Conservation groups have flagged this as a slow-moving but serious biodiversity concern — one that's easy to overlook because it doesn't have the dramatic visibility of something like a wildfire or flood, but adds up over years of unchecked spread.
What a federal fix could look like
Advocates say a national approach wouldn't need to reinvent the wheel. Countries with dedicated invasive species databases make it simple for retailers and consumers to check whether a plant is a known risk before it ever reaches a checkout counter. A similar federal database for Canada, paired with consistent rules on what can and can't be sold, would take the guesswork out of a system that currently varies wildly depending on where you live.
For now, the responsibility largely falls on individual buyers to do their own research — something conservation groups admit is an unrealistic expectation for the average person picking out plants for a backyard garden.
Until clearer national standards arrive, experts recommend checking with local conservation authorities or provincial invasive species councils before adding ornamental plants to your garden, and opting for native alternatives where possible.
Source: CBC News
