The Major Threat Canada Thistle Poses To Your Garden

Easily recognizable due to its vase-shaped purple flowers with dandelion-like seeds, Canada thistle (Cirsium arvense) is a particularly aggressive invasive plant. Despite its name, Canada thistle is not a plant native to Canada. This noxious weed likely came over with early settlers to North America before New England residents blamed its spread on French traders from Canada. However this weed got here, it poses an incredible threat to any plants growing in your garden thanks to its insidious growth patterns.

Thanks to its rhizomatous roots (which grow horizontally to the ground and often pop up elsewhere as another plant), this plant can quickly burst into thick clusters that push out native plants and are known to harm crop production. The resulting spread is perhaps why it is also known as creeping thistle. This can be particularly concerning if you have a vegetable garden, as this thistle drains nutrients from the soil, uses up a lot of soil moisture, and secretes chemicals that are toxic to nearby plants. It's definitely a toxic perennial you don't want to see in your yard.

To prevent harm to your garden, make sure you know how to identify aggressive Canada thistle. Check to see if the stem is smooth and spineless. Other types of thistles, including native thistles that are not invasive, have spiny stems. This invasive thistle grows purple, puffball flowers in clusters that give off a vaguely sweet scent. The leaves of a Canada thistle are glossy green and have spiny edges with white hairs on the bottom. It can grow between 3 and 5 feet tall.

Despite its bright and pretty blooms, don't mistake this deceiving invasive weed for a flower. Canada thistle spreads quickly and easily thanks to the fluffy plumes on its seeds. One plant can produce up to 10,000 seeds, making it incredibly important to prevent the spread as soon as you notice it in your garden. New growth can pop up anywhere, but especially in disturbed soils.

Don't start to panic if your garden has been taken over by Canada thistle. There are steps to take to get rid of this highly invasive weed to protect your vegetables and other plants. The best thing is to take action as soon as you see a Canada thistle spring up in your garden, before it starts killing or crowding out your plants. Common ways to banish thistle weeds from your yard include repeated mowing and the use of an appropriate herbicide.