Invasive vs. native garden species: Learning what to pull and what to plant

The City of Toronto’s Patricia Landry can’t resist pulling out the invasive dog strangling vine that she notices in the Glen Stewart Ravine during an interview with Global News.

“It’s one of our worst invasives,” she says. “It’s an ongoing battle.  We never stop.”

Sneaky, creeping and costly, invasive plants are everywhere.

“It’s hundreds of thousands of dollars, yes,” says Cara Webster, a natural resource management supervisor for the City of Toronto.

Webster has been paying close attention to the projects underway in the Glen Stewart Ravine because the location is considered “environmentally significant.”

“There was a lot of common buckthorn in the understory, which makes it dense. You can’t see through a forest so, when you go in and release the shade, then the native species can thrive,” Webster says.

1:50 Growing trend in planting native species is taking root

The city has an evolving list online at toronto.ca of the top 10 prohibited plants that threaten the environment and/or human health and safety.

But there are dozens and dozens of invasive plants many Toronto residents have intentionally planted or allowed to flourish in their own backyards, perhaps not knowing their aggressive nature. Plants like English ivy and periwinkle (vinca) can literally choke out other species and once they take hold, successfully removing these plants can prove to be bewildering.

There are Facebook support groups dedicated to eradicating the fiercely invasive creeping bellflower but there are also a growing number of groups and garden experts on social media who focus on a trend that aims to reconnect habitat and preserve biodiversity: native planting.

“Definitely, there’s been a big shift and we’re moving in the right direction. People recognize the importance of creating habitat on their own property,” Landry says.

As Laundry stands in a native plant-filled East Toronto garden, she points out Canada anemone, herb robert and yarrow.

“The species that are here evolved over thousands of years and they support wildlife. … When we lose native species, then we lose all of those other species that depend on those plants,” Webster says.

The city says Toronto is home to a wide range of pollinators, including 364 species of bees and 112 species of butterflies. Native plants are those that grew naturally in a region where they evolved, adapting to the local land, and pollinators need native plants just like native plants need pollinators.

“This is making our landscapes more sustainable,” Landry says. “We’re in this climate crisis, so it’s making our gardens and our landscapes more resilient to these changes.”

Many native plants can require less water, too.

But prioritizing native plants doesn’t mean Toronto residents should rip out most of their non-native, hybrid or ornamental plants, Landry says.

“I don’t want people to feel like they have to go all native to be doing the right thing gardening-wise. If you plant three, four, even five native species in your garden, you are helping the environment,” she says.