Invasive plants beat native trees to space, sun and water

There is a new list of the top offenders in B.C., and experts hope it will encourage the public to weed out the invaders.

For many residents, the names of the foreigners should sound very familiar: English ivy, Himalayan blackberry, and Scotch broom.

Those are just three of 13 common plants that are beating native plants to space, sun and water and taking over and damaging local ecosystems, according to the Invasive Plant Council of B.C, a non-profit charity organization.

Gail Wallin, the council's executive director, says many of the problem plants gained a foothold here through people's gardens and then spread to the wild.

English ivy is often planted to grow up buildings, but it can also choke out trees if it spreads into a forest.

Scotch broom, brought to beautify highways, has pushed out local plants, and Himalayan blackberry has also taken root in local parks and roadsides.

In many places such as Stanley Park and Jericho Park, volunteers are already working hard to rip out invasive species.

The Invasive Plant Council of B.C is hoping the new list will help to stop gardeners from planting problem species, and nurseries from selling the exotic plants.

"You can still buy many of the plants today that people recognize are totally invasive," Wallin said.

One retailer, GardenWorks, has purged its shelves of 10 invasive species, starting this season.

Scott Pearce, the manager of green goods for GardenWorks, said most customers welcome the change but a few object, saying they need plants such as English ivy for ground cover.

"You say, 'let me show you a couple of alternatives' and most people are open to that," said Pearce.

"We're hoping some of the plants that are identified as being invasive and are causing problems will just slowly work their way out of the system as they're not being sold anymore, and we start doing more proactive things like the ivy pulls and that kind of thing."

Growing problem

But Wallin warns, even if B.C. gardeners are able to get control of those invasive plants that are already here, global warming could open the door for a whole new invasion.

"We have a current problem with some plants, there's no doubt, and they're well established, but the bigger threat is all the potential plants that can come in," she said.

"B.C. is becoming a warmer place. We don't have the harsh winters. We're seeing more trade … With trade and travel and climate change, we have the ability here in British Columbia to be an explosion of invasive plants over the next decades."

The normally mild winters on B.C.'s south coast already make it a province with a significant invasive species problem, said Todd Boland, a research horticulturist from Memorial University in St. John's Newfoundland.

"When you get these growing into the natural areas, suddenly a natural food source for a particular organism is no longer available, and they have this foreign plant instead which they can't take advantage of," he said.

Once established, invasive plants can be almost impossible to remove. "Without a nuclear bomb? It's very, very difficult," joked Boland.