Creeping flower and purple loosestrife are two non-native species found throughout North America. And although the plants are beautiful at first glance, experts warn that they are highly invasive and have the potential to choke out entire areas of native species. Glen Koblun, director of Native Plant Solutions in Winnipeg, says creeping flower is invasive because it is made up of “elastic” materials and the plant prefers urban, wet and shady conditions, making it more of a problem for homeowners than farmers. “The roots are very rich and have a lot of reserves and can grow back even if you pull them out,” he said. “It’s become a problem, more aesthetically.” Creeping flower is difficult to control because there is no simple way to manage the plants, Koblun says, and cultural, chemical or mechanical solutions don’t fix everything. Mowing the grass helps prevent the seeds from setting in the soil, Koblun says, but he cautions against fertilizing or littering any part of the creeping flowers to prevent further reproduction. The lack of intensive labor required to successfully pull weeds over the cosmetic pesticide ban is causing an “explosion” of weeds in Winnipeg, says Glen Koblun, director of Native Plant Solutions. (Émile Lapointe/Radio-Canada) Pulling the invasive plant by hand is the best approach for Winnipeg homeowners, he says, because of a ban enacted in 2014 by the former NDP government that ended the use of so-called “cosmetic pesticides” — optional or optional pesticides to improve the appearance of a lawn. They called it a victory for the environment and people’s health. However, many property owners complained that they had to use weed control products that were more expensive and less effective. Last April, the Manitoba NDP succeeded in delaying the province from lifting the ban. The lack of intensive labor required to successfully pull weeds by hand combined with the pesticide ban has led to an “explosion” of weeds in Winnipeg, Koblun says. A single purple loosestrife plant can spread over two million seeds.- Lauren Bell, Invasive Species Center Purple Loosestrife, on the other hand, is just as invasive in rural areas, he says, adding that it would be in the province’s best interest to remove the flowers from highways. He called the creeping flowers and purple loose flowers “chameleons” because of their ability to survive periods of drought without flowering. “Moisture really reproduces the ability of these plants to grow,” he said. “The explosion of what we’re seeing isn’t necessarily an explosion of new infestations — it’s just laying dormant until it reaches ideal conditions to flourish.” Kolbun says he’d like to see the province treat invasive species the same way it does Dutch Elm disease, where the entire plant is dug up and burned or landfilled. Non-native plants are able to thrive because they often don’t have the same constraints as native species, says Lauren Bell, invasive species program manager at the Invasive Species Center in Sault Ste. Marie, Ont. (Émile Lapointe/Radio-Canada) “A single purple loosestrife plant can spread over two million seeds,” said Lauren Bell, invasive species program manager at the Invasive Species Center in Sault Ste. Marie, Ont., told Radio-Canada in an interview. Bell says non-native plants are able to thrive because they often don’t have the same limitations as native species. Flooding can hamper management tactics, Bell says, and will likely increase their spread. Purple Loosestrife is particularly invasive in marshy areas because it is an aquatic species, giving it a leg up on other native plants. “We don’t have the same climate, the same factors that keep it together [invasive] populations of species under control that you have in that species’ native range,” Bell said. Defense tactics against invasive plants depend on where you are, he says, but their spread appears to be decreasing due to biological control, education and public involvement. The spread of invasive species doesn’t mean Canadians should avoid planting non-native species, but there are benefits to planting native species, Bell said. Controlling existing populations as well as education and outreach are both key to preventing the spread of invasive species, Bell says.
