​WEEDS OF MASS DESTRUCTION

A plant is considered invasive when it is introduced to an environment other than its natural habitat and grows successfully. These foreign plants have the potential to spread rapidly and take over large areas of land, as they typically have no natural predators (animals or diseases). This lack of predators gives foreign plants an advantage over native plants as they compete for resources such as water and space. If they are not adequately controlled, invasive species can choke out native species and alter established natural ecosystems. Invasive plants are also a problem on farms, where they can infest crops or spread into pasture and affect livestock.

How did they get here?

As humans developed technologies such as ships and airplanes that let them travel the world, plants tagged along for the ride. Some now-invasive plant species were brought to new habitats on purpose, for example creeping bellflower, which used to be planted in many gardens. These plants were brought to new environments to serve decorative and food crop purposes, but some species grew out of control and became pests.  Other plants were introduced to forgein habitats unintentionally, often through accidental seed dispersal. Canada thistle is an example of this. Did you know it is Scotland's national flower? 

 

What is being done?

In Alberta, there is a document known as the Weed Act that legislates the control of invasive plants. Weed Inspectors are hired by various counties to scour the province for outbreaks of foreign species, and issue notices to ensure they are dealt with. Invasive weeds are categorized as either noxious or prohibited noxious - noxious plants must be controlled, whereas prohibited noxious plants must be destroyed. Control is typically achieved via pulling, mowing, or applying herbicide, but there are a variety of options available depending on the weed. New solutions are forever being sought after!

What does this have to do with me?

Even if you've never noticed them, invasive plants are all around us. Plant a garden, and there's a good chance you will have to deal with some Canada Thistle. Take a ride on the Edmonton LRT in the summer, and you will see Common Tansy along the tracks. Go hiking in Banff National Park, and you will encounter Oxeye Daisies. Many of the foods that are staples in our diets come from crops that farmers must monitor closely to avoid infestations of noxious weeds. If you owned a property that became home to an invasive species, it would be your responsibility to decide how to control the plants. Ultimately, invasive plants are a threat to the biodiversity and function of the environment you call home.

Invasive plants - what are they?