What Does Canada Thistle Look Like?

If you’ve ever seen an unidentified weed in your yard, you may be wondering what it was, and how it got there. Homeowners and amateur gardeners are constantly on the lookout for new methods to keep their gardens and lawns looking the best they can, so it’s critical for you to see all weeds as they sprout, so you can remove them before they do any harm in the long run.

Below, we’ll take a closer look at the weed Canada Thistle, including what it looks like, where it grows, how to get rid of Canada Thistle, and much more. We’ll give you all you need to know about this invasive weed so that you can learn how to best eliminate it from your yard!

So, what does Canada Thistle look like? Let’s go find out.

What is Canada Thistle?

Canada Thistle, or Cirsium arvense, is a weed that spreads fast and can take over areas where it is present, thus making it an invasive species. It’s also known as Creeping Thistle or Field Thistle. Although it was originally native to Europe, western Asia, and northern Africa, it has been introduced to many different countries as an invasive weed.

The Canadian thistle is good for pollinators that feed on nectar. It was one of the top producers of nectar sugar in Britain in 2016. Nonetheless, this does not detract from the fact that it is one of the world’s worst invasive weed species.

Where Does Canada Thistle Grow?

Canada thistle is a perennial plant that grows and spreads by seed or deep root systems. It can reach a height of up to 5 feet in suitable conditions.

It does not reproduce or spread through rhizome activity, but root buds develop on existing roots, resulting in another offshoot stem and plant. As a result, it develops vast clonal colonies that cluster together.

Canadian Thistle grows in disturbed locations and may be found along roadsides, pathways, natural areas, pasture borders, forest and field margins, mining sites, waste areas, and unkept gravel pits. This plant thrives after new road construction projects, as well as housing and development projects in the countryside.

How to Identify Canada Thistle

Before you can work to eliminate Canada Thistle from your lawn or garden, you need to know exactly what it looks like. Here are the visuals to be looking for when you are trying to identify Canada Thistle at home or in your local areas.

Visual Characteristics 

The leaves of this plant are spiny, although the stems from which they grow are smooth and a forest green color. The stems are anywhere from 1 foot long to 5 feet long. These spiny leaves are lobed, alternate along the stems, have jagged edges and can be up to 8 inches in length.

At the top of their tall stems, the flowers of the Canada Thistle are purple-pink in color and look like little spiky spheres. These central flower clusters, or inflorescences, are small and about .5-1 inch in diameter. Its seeds are 4-5 millimeters in length, and they have little feathers at one end to aid in wind-borne seed dispersal.

Growth Stages

The plant may blossom from seed in one year, yielding seeds that may grow the following year, as the weed is a perennial.

Seedlings develop as tiny rosettes in the fall or early spring, then bolt into erect branched flowering stems. Flowers begin to blossom in late June and continue to bloom until August.

This weeds is most recognizable around the middle of July, which is when flowers turn to seedheads and have those distinct white fluffy tops. The “fluff” is inhabited by seeds that may travel and spread throughout new areas.

Other Unique Traits

The Canada Thistle weed smells quite strongly and emits a floral fragrance that is very powerful and attracts many different types of bugs that both pollinate and eat the weed. It is better at attracting honeybees and other pollinating insects than other plants, and these fragrance emissions increase as the plant matures. They decrease after pollination, however.

Plants That Look Like Canada Thistle

Canada Thistle, when in bloom, can look somewhat like Red Clover, due to the fact that they both produce spherical red or pink flower heads. However, any closer inspection will tell you which weed it is, as the Thistle is much more spiky and the flowers are more compact.

Additionally, you might get this weed mixed up with Dandelions as they both have the white fluffy seeds that grow after their flowers die. To tell them apart, Canada Thistle is a lot taller than Dandelion weeds, and the stems are heavier and full of spikes.

How to Get Rid of Canada Thistle

Eradicating Canada thistle is more difficult than the majority of weeds, because its roots can grow very deep. ´╗┐Also, the most important thing to remember when working to rid your yard of Canada Thistle is to avoid cutting down any plants during their flowering season since new seeds will develop with each flower.

The ideal way to get rid of Canada Thistle organically is to dig up the entire plant via the root from which it sprouts. If you opt to do this method, make sure to wear thick gloves to protect your hands, and wear old clothing since the thistles are spiny and can rip pieces of cloth.

You can also mix vinegar and dish soap in a spray bottle and spray that mixture over the leaves of the Canada Thistle until it is completely soaked. Do this once a day until the weed dies.

Canada Thistle is most easily eliminated using any of the most common weed killers. The Canada Thistle will be destroyed by a non-selective weed killer that uses glyphosate. However, you must be cautious since a non-selective herbicide will kill any other plants it comes into contact with, including your ornamental or vegetable plants.

Final Thoughts

As it is with all weeds, knowing what one looks like is the best way to keep Canada Thistle off your grass. If you can identify this pesky weed early on and get rid of it before it becomes a problem, you’ll be able to avoid issues later on.

Thanks for reading this post about Canada Thistle. We hope that by taking into account all we’ve said about Canada Thistle, you’ll be better informed about this invasive weed. If you think you might have Canada Thistle in your lawn or garden, there are certain visual traits that may be of help in identifying it.

If you’re not sure whether a plant in your garden is Canada Thistle, please contact us. We want to make sure that it doesn’t spread through your neighborhood and that it doesn’t harm to your lawn or home. Thank you for taking the time to read this article, and best of luck with your weeding!