When many people think of invasive plant species, they probably think about its effect on ranchland and grassland in the region. However, the Invasive Species Council of BC (ISC) wants home gardeners to be aware of the invasive plants that might be lurking in their gardens, and be mindful of them when buying or swapping plants or seeds.
“Most of the invasive species—about 60 per cent—are deliberately planted in gardens,” says Gail Wallin, the ISC’s executive director. She points to baby’s breath as one culprit. “It hops the fence and spreads quite rapidly.”
Baby’s breath is just one of 26 invasive species targeted in the ISC’s Grow Me Instead booklet. The booklet lists the most “unwanted” invasive plants frequently found in gardens across B.C., and then lists more suitable—but equally beautiful and functional—non-invasive plants that gardeners can use instead in a range of growing zones and conditions throughout the province.
Although some of these plants are still sold in stores, Wallin says that the ISC has been successful in getting invasive species out of many garden centres. “But people can still pick them up at local hardware or big-box stores, where they’re often described as spreading widely and covering a lot of ground.”
Many invasive species are also traded amongst gardeners, and Wallin says that the ISC’s PlantWise program aims to educate gardeners about what they should—and should not—be putting in their gardens. She also notes that invasive plants can unwittingly end up in people’s gardens via bits of root left in soil that is transferred.
“Many of these plants have come from somewhere else,” says Wallin, brought by people who came here from another country but wanted to bring familiar plants with them. “The plants didn’t bring their natural predators with them, which is a good thing, but it means there’s nothing here to control them.”
She also warns that just because something grows naturally in one part of the province does not mean it is suited for another part; it could prove to be invasive if it is taken too far from its usual area. “Cow parsnip is not so bad if its natural range changes due to climate, but we do care if you drive it 300 miles to where it doesn’t belong.”
Invasive plants do not just spread rapidly; they can (as in the case of burdock) be a hazard to dogs and horses, or can choke out other foliage in the area. Wallin says that English ivy is classed as an invasive species, and is a significant problem in the Lower Mainland and Vancouver Island, where it is often used on houses and other buildings. “That little vine covers big trees, and smothers them.”
In addition to Grow Me Instead, the ISC offers a user-friendly mobile app and website (www.beplantwise.ca) which shows users how to choose expert-suggested, non-invasive plants for every growing zone. The site also offers tips and resources, including how to become a PlantWise ambassador in your community, and where to report sightings of invasive plants.
“We want people to know what they are buying, and to buy wisely,” says Wallin.