10 Ways to Get Rid of Canadian Thistles (Permanently)

PDF download Download Article
PDF download Download Article

Canadian thistle is notorious for its spiky leaves, purple flowers, and rapid growth rate. The fluffy seeds that grow in the spring are light enough to catch on the wind, so the thistle can spread rapidly, taking over entire habitats in the blink of an eye. If you have Canadian thistle in your area, you may need to spend multiple seasons trying different management techniques to get rid of it completely. Prevention and early treatment are key, so don’t wait!

1

Spray herbicide on the infestation.

PDF download Download Article
  1. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/4\/4e\/Get-Rid-of-Canadian-Thistles-Step-1.jpg\/v4-460px-Get-Rid-of-Canadian-Thistles-Step-1.jpg","bigUrl":"\/images\/thumb\/4\/4e\/Get-Rid-of-Canadian-Thistles-Step-1.jpg\/v4-728px-Get-Rid-of-Canadian-Thistles-Step-1.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>\u00a9 2024 wikiHow, Inc. All rights reserved. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. This image is <b>not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. This image may not be used by other entities without the express written consent of wikiHow, Inc.<br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    Start by spraying a broadleaf herbicide on the thistle patch in the early spring before it has a chance to flower. Follow up with a second application in the late fall to kill the roots.
    • Look for an herbicide with aminopyralid, glyphosate, or chlorsulfuron on the ingredients list.
    • Herbicides are dangerous chemicals, and they can cause irritation. Always read the warning label on your bottle of herbicide, and wear gloves and eye protection to stay safe.
    2. Advertisement


2

Pull the thistle by hand if it isn’t flowering.

PDF download Download Article
  1. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/1\/1b\/Get-Rid-of-Canadian-Thistles-Step-2.jpg\/v4-460px-Get-Rid-of-Canadian-Thistles-Step-2.jpg","bigUrl":"\/images\/thumb\/1\/1b\/Get-Rid-of-Canadian-Thistles-Step-2.jpg\/v4-728px-Get-Rid-of-Canadian-Thistles-Step-2.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>\u00a9 2024 wikiHow, Inc. All rights reserved. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. This image is <b>not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. This image may not be used by other entities without the express written consent of wikiHow, Inc.<br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    If the thistle isn’t flowering, put on a pair of gloves and gently tug the entire plant upward by the stem. [1] If the thistle is flowering, pulling it out will only spread the seeds, so you should pick a different method.
    • If you pull the thistle and it doesn’t have any flowers on it, you can throw the stems in with your compost pile or yard debris bin.
    • If you accidentally pull a thistle that has flowers on it, bag it and take it away to be burned. Flowering thistles can spread seeds even if they aren’t in the ground.
3

Mow the thistle with a lawn mower.

PDF download Download Article
  1. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/a\/a5\/Get-Rid-of-Canadian-Thistles-Step-3.jpg\/v4-460px-Get-Rid-of-Canadian-Thistles-Step-3.jpg","bigUrl":"\/images\/thumb\/a\/a5\/Get-Rid-of-Canadian-Thistles-Step-3.jpg\/v4-728px-Get-Rid-of-Canadian-Thistles-Step-3.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>\u00a9 2024 wikiHow, Inc. All rights reserved. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. This image is <b>not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. This image may not be used by other entities without the express written consent of wikiHow, Inc.<br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    [2] Do an initial mow in late June to catch the thistle before it starts flowering. As the thistle regrows, you’ll have to mow it again throughout the late summer to keep it from spreading seeds. [3]
    • After using your mower on thistle, inspect it carefully and clean it off. If there are any seeds stuck to your mower, bag them and burn them.
    2. Advertisement
4

Introduce goats to graze if the thistle is young.

PDF download Download Article
  1. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/6\/6a\/Get-Rid-of-Canadian-Thistles-Step-4.jpg\/v4-460px-Get-Rid-of-Canadian-Thistles-Step-4.jpg","bigUrl":"\/images\/thumb\/6\/6a\/Get-Rid-of-Canadian-Thistles-Step-4.jpg\/v4-728px-Get-Rid-of-Canadian-Thistles-Step-4.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>\u00a9 2024 wikiHow, Inc. All rights reserved. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. This image is <b>not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. This image may not be used by other entities without the express written consent of wikiHow, Inc.<br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    Try to bring the goats in during early spring before the seeds start to spread. They’ll chomp the seedlings down and keep them from flowering. [4]
    • Like mowing, you may have to allow your animals to graze multiple times throughout the year to keep the thistle from flowering.
    • Goats are the most effective at grazing, but sheep, cattle, horses, donkeys, and llamas will also eat it.
5

Till the soil.

PDF download Download Article
  1. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/1\/10\/Get-Rid-of-Canadian-Thistles-Step-5.jpg\/v4-460px-Get-Rid-of-Canadian-Thistles-Step-5.jpg","bigUrl":"\/images\/thumb\/1\/10\/Get-Rid-of-Canadian-Thistles-Step-5.jpg\/v4-728px-Get-Rid-of-Canadian-Thistles-Step-5.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>\u00a9 2024 wikiHow, Inc. All rights reserved. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. This image is <b>not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. This image may not be used by other entities without the express written consent of wikiHow, Inc.<br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    Use a hoe to till the soil at least 4 in (10 cm) deep and remove the majority of the thistle. This works best on young plants that aren’t flowering yet, so try this out on young, thin patches. [5]
    • It’s important to till as far down as you can. Shallow tilling will actually encourage the spread of Canadian thistle.
    • On its own, tilling isn’t a very effective method. It works best when you follow up with an herbicide application.
    2. Advertisement
6

Thin the thistle out with a prescribed burn.

PDF download Download Article
  1. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/a\/ac\/Get-Rid-of-Canadian-Thistles-Step-6.jpg\/v4-460px-Get-Rid-of-Canadian-Thistles-Step-6.jpg","bigUrl":"\/images\/thumb\/a\/ac\/Get-Rid-of-Canadian-Thistles-Step-6.jpg\/v4-728px-Get-Rid-of-Canadian-Thistles-Step-6.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>\u00a9 2024 wikiHow, Inc. All rights reserved. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. This image is <b>not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. This image may not be used by other entities without the express written consent of wikiHow, Inc.<br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    Contact a local fire team in your area to come out and set fire to the thistle patch. Follow up a few months later with a second controlled burn if you need to. [6]
    • Controlled burns don’t work very well on their own. They’re most effective when you follow up with an herbicide application.
    • Never try to do a controlled burn on your own without the supervision of a professional.
7

Check hay and straw for weed seeds.

PDF download Download Article
  1. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/f\/f5\/Get-Rid-of-Canadian-Thistles-Step-7.jpg\/v4-460px-Get-Rid-of-Canadian-Thistles-Step-7.jpg","bigUrl":"\/images\/thumb\/f\/f5\/Get-Rid-of-Canadian-Thistles-Step-7.jpg\/v4-728px-Get-Rid-of-Canadian-Thistles-Step-7.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>\u00a9 2024 wikiHow, Inc. All rights reserved. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. This image is <b>not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. This image may not be used by other entities without the express written consent of wikiHow, Inc.<br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    If you purchase hay and straw, make sure it’s certifiably weed-seed free before you bring it onto your property. If you aren’t sure, check the bales and make sure you aren’t introducing Canadian thistle (or any other weeds) into the area.
    • Canadian thistle seeds are brown and only about 1 mm (0.039 in) wide. They can be hard to distinguish from other seeds, so if you spot any seeds at all in your hay or straw, don’t bring it onto your property.
    2. Advertisement
8

Plant perennial grasses in barren areas.

PDF download Download Article
  1. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/4\/4f\/Get-Rid-of-Canadian-Thistles-Step-8.jpg\/v4-460px-Get-Rid-of-Canadian-Thistles-Step-8.jpg","bigUrl":"\/images\/thumb\/4\/4f\/Get-Rid-of-Canadian-Thistles-Step-8.jpg\/v4-728px-Get-Rid-of-Canadian-Thistles-Step-8.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>\u00a9 2024 wikiHow, Inc. All rights reserved. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. This image is <b>not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. This image may not be used by other entities without the express written consent of wikiHow, Inc.<br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    If you have an area on your property that’s mostly dirt, throw some grass seeds down and let them take root. The thistle will have a harder time rooting and growing in an area that already has plants in it.
    • Try planting switchgrass, fountain grass, or reedgrass.
9

Release weevils and beetles in the area.

PDF download Download Article
  1. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/1\/1d\/Get-Rid-of-Canadian-Thistles-Step-9.jpg\/v4-460px-Get-Rid-of-Canadian-Thistles-Step-9.jpg","bigUrl":"\/images\/thumb\/1\/1d\/Get-Rid-of-Canadian-Thistles-Step-9.jpg\/v4-728px-Get-Rid-of-Canadian-Thistles-Step-9.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>\u00a9 2024 wikiHow, Inc. All rights reserved. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. This image is <b>not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. This image may not be used by other entities without the express written consent of wikiHow, Inc.<br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    Cassida rubiginosa, Rhinocyllus conicus, Trichosirocalus horridus , and Urophora cardui are all natural predators of Canadian thistle. However, you need to get a permit through the US Department of Agriculture before you use this method. Once you get your permit, the USDA can point you in the direction of a seller.
    • Some species of insects might be more suited for areas than others. It’s important to get a permit and check with your local laws before using a biological control method.
    2. Advertisement
10

Report Canadian thistle to your local government.

PDF download Download Article
  1. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/5\/57\/Get-Rid-of-Canadian-Thistles-Step-10.jpg\/v4-460px-Get-Rid-of-Canadian-Thistles-Step-10.jpg","bigUrl":"\/images\/thumb\/5\/57\/Get-Rid-of-Canadian-Thistles-Step-10.jpg\/v4-728px-Get-Rid-of-Canadian-Thistles-Step-10.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"<div class=\"mw-parser-output\"><p>\u00a9 2024 wikiHow, Inc. All rights reserved. wikiHow, Inc. is the copyright holder of this image under U.S. and international copyright laws. This image is <b>not<\/b> licensed under the Creative Commons license applied to text content and some other images posted to the wikiHow website. This image may not be used by other entities without the express written consent of wikiHow, Inc.<br>\n<\/p><p><br \/>\n<\/p><\/div>"}
    They might even be able to give you a grant or assistance. If you’re out and about and happen to see it, tell them exactly where it is so they can go out and treat it.
    • Once Canadian thistle is established, it’s really hard to get rid of. Prevention and early treatment are key.

Expert Q&A

Search
Add New Question
  • Question
    How do you kill Canadian thistle naturally?
    Tyler Radford
    Plant Specialist
    Tyler Radford is a Plant Specialist at Hollie’s Farm & Garden in Tampa, Florida. With over nine years of experience, Tyler specializes in gardening, planting, mulching, and potting. Hollie’s Farm & Garden is a full-service landscape nursery offering landscape supplies including trees, shrubs, mulch, and flagstone.
    Tyler Radford
    Plant Specialist
    Expert Answer
    For a natural alternative, try using a vinegar-based weed spray to kill your Canadian thistles.
    Thanks! We're glad this was helpful.
    Thank you for your feedback.
    If wikiHow has helped you, please consider a small contribution to support us in helping more readers like you. We’re committed to providing the world with free how-to resources, and even $1 helps us in our mission. Support wikiHow
    Yes No
    Not Helpful 1 Helpful 10
Ask a Question
200 characters left
Include your email address to get a message when this question is answered.
Submit
      Advertisement

      Tips

      Submit a Tip
      All tip submissions are carefully reviewed before being published
      Submit
      Thanks for submitting a tip for review!
      Advertisement

      Warnings

      Advertisement

      You Might Also Like

      How to Get Rid of Bamboo in Your Yard
      How to Get Rid of Ant Nests in Potted Plants
      How to Drive Away Gnats for Good: Easy DIY Methods
      How to Remove Frogs from Your Home or Garden
      How to
      Use a Weed Whacker
      How to Kill a Tree with or without Chemicals
      How to
      Start a Weed Whacker
      How to
      Get Rid of Snakes
      How to Remove Ticks In and Around Your House
      How to
      Identify Stinging Nettle
      How to
      Get Rid of Crows
      How to Kill and Remove a Tree Stump Yourself
      How to
      Identify Poison Sumac
      How to
      Catch a Snake
      Advertisement

      References

      1. ↑ Ben Barkan. Garden & Landscape Designer. Expert Interview. 14 April 2020.
      2. ↑ Ben Barkan. Garden & Landscape Designer. Expert Interview. 14 April 2020.
      3. ↑ https://www.mda.state.mn.us/plants/pestmanagement/weedcontrol/noxiouslist/canadathistle
      4. ↑ Ben Barkan. Garden & Landscape Designer. Expert Interview. 14 April 2020.
      5. ↑ https://www.extension.purdue.edu/extmedia/FNR/FNR-436-W.pdf
      6. ↑ https://www.extension.purdue.edu/extmedia/FNR/FNR-436-W.pdf

      About This Article

      In other languages
      Thanks to all authors for creating a page that has been read 19,685 times.

      Did this article help you?

      Advertisement