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HOW TO KNOCK INVASIVE SPECIES FROM YOUR YARD
By LADY BUG, with files from NEWS CANADA
Invasive plant species can be devastating, havoc-wreaking terrors to plants, biodiversity, wetlands and farmers’ fields.
They are more than a mere nuisance to gardeners and farmers – they can crowd out the surrounding native vegetation, wipe out important natural habitat areas and choke out wildlife. The plants compete with native flowers and crops for sunlight, moisture and nutrients.
According to Environment and Climate Change Canada, the economic impact of invasive plants in crops and pastures is $2.2 billion each year. This is because invasive plants reduce crop yields and quality, while increasing costs of weed control and harvesting.
Reaching a whopping height of five metres, invasive Phragmites, or common reed, can be hard to miss and is infamous as Canada’s worst invasive plant species
While there’s no clear answer on how this perennial grass made its way from Europe to Canada, ecosystems across the country have been feeling its impact for decades.
Like most invasive plant species, this reed is known to be devastating to the native plants around it. Its tall, rough, beigey-tan stems with blue-green leaves and large, dense seed head spread quickly and aggressively, competing with native species for sunlight, water and nutrients – often winning.
The invasive species releases a toxin from its roots that can kill nearby plants. Once it starts to spread it begins to crowd out the surrounding native vegetation, wiping out important natural habitat areas and choking out wildlife.
While every province has its own recommendations for dealing with the problem, the options are often similar, ranging from mowing and cutting to flooding, compression and rolling.
But, according to Pierre Petelle, president and CEO at CropLife Canada, the most effective option is a well-timed herbicide treatment.
“Unlike other removal methods, herbicides get to the root of the problem, effectively killing the entire plant. Other methods like cutting, if done without an herbicide treatment, may actually do little more than stimulate the growth of reeds and damage the surrounding ecosystem,” he says.
Herbicides might just give some of the wetlands and beaches currently struggling with the invasive species another chance.
Another example is wild parsnip, a member of the carrot and parsley family that forms dense stands that can spread quickly. The plant is native to Europe and Asia and was brought to North America by European settlers. Wild parsnip was originally grown for its edible root, but it has gotten out of hand and spread across the country.
The seeds of wild parsnip are easily spread by wind and water, or even equipment such as a mower. While the root of the plant is edible, the sap of the plant can cause human skin to react to sunlight, triggering burns, rashes or blisters.
Because many invasive species have negative impacts like these, it’s imperative to eradicate them immediately. If it’s a small infestation, it may be possible to dig the root in the spring, but mechanical control is often difficult for large infestations.
In most cases, herbicides can tackle invasive species. Unlike other removal methods, herbicides literally get to the root of the problem, effectively killing the entire plant.
And they are safe to use, say experts. Before any pesticide can be sold, it must be approved by Health Canada. The regulatory process is stringent, world renowned and ensures all pesticides used in the country are safe for both people and the environment.
Of course, if you are like me and wary of pesticides, another way is to just pull out or dig up invasive species manually. I recall a presentation at the visitors’ centre at Crawford Lake Conservation Area in Campbellville in Milton many years ago during which we were informed that one of the ladies from the Crawford family that owned the land which they later donated to the conservation authority had introduced a groundcover that she loved to the area. The glossy green leaves and the pretty purple blooms of periwinkle are a sight to behold in spring. Until you realize that it grows by leaps and bounds and can cover and eventually choke everything in its path. In the environmentally sensitive area, they had teams of volunteers fan out to pull the plants out by the root.