I believe that this is what the weed is called, here is a picture

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It is very invasive and I don't know how to kill it. I tried Weed b-gone but it only kills the leaves and does nothing else. It's hard to root it because its root are deep. I live in Canada and there isn't that many chemical options to get rid of this annoying weed. However I will be traveling to North Carolina for xmas and I was hoping to get something to destroy this weed.

What product do I need to get to annihilate this weed? I have this weed in my moss garden and grass. I also have a dog, so I am hoping for something that will kill this weed and not harmful to my dog in case she eats the product by accident.

  • You can always eat them. Thistles are edible and Canada thistle is said to be 'remarkably tasty' according to wildflowers-and-weeds.com. They may grow back, but it's more food. :) Just a thought. I understand the roots themselves may be a hindrance, and you might not be keen on eating thistles, especially while they're growing in your moss. Be sure to snip off any flowers to prevent seeding, whatever you do. Dec 16, 2014 at 8:47
  • I don't even like touching them due to the thorns but I will keep that in mind in case I run out of food
    – Huangism
    Dec 16, 2014 at 13:08

5 Answers 5


Professionals use a product that contains clopyralid. This chemical messes with the plant's auxins, causing it to grow too fast to support itself, or into strange shapes/growth patterns for a couple of weeks before the plant finally dies.

This chemical strongly affects plants from the Fabaceae, Solanaceae, and Asteraceae (bean, potato, and sunflower families, respectively). Thistles are in the sunflower family.

Note: This product doesn't deactivate on contact with organic matter, like glyphosate (Roundup) does, and it may linger in the soil for quite some time.

  • I will keep this in mind, luckily I don't have those plant.
    – Huangism
    Dec 15, 2014 at 19:26
  • @Huangism yes you do. "Thistles are in the sunflower family" and "This chemical strongly affects plants from the ... sunflower families" May 16, 2016 at 17:40

Manual removal of the plant and root to a depth of at least three inches will do the job. The more root you get the less likely it will return.

Also a mulch with or without a landscape fabric will prevent new weeds from getting a good hold. This might work in your moss garden as moss does not require a lot of soil.

There are all kinds of weeding tools that can help you get out roots. I think you can control this weed without the use of pesticides just by diligent removal in the active growing seasons of spring and summer.

  • The moss I have are not just those regular moss you see on corners and such. They are more like plant moss, I am not sure what the term is but they do require soil. The ones in my moss garden I try to dig as deep as I can. The root literally goes around this big rock I have and pushes out beside the rock, it is ridiculous. Should I get a weeding tool to remove these? Are there any chemical solutions for this weed?
    – Huangism
    Dec 15, 2014 at 18:08
  • Pretty much what I found clearing cow pasture of Bull Thistle. Mow them, poison them and they just came back. Wait till they bloom, spear them two inches below the ground with an irrigation shovel to cut off the crown and leave the plants on the surface as mulch. For some reason, they take 2-3 years to come back after that treatment. Dec 16, 2014 at 1:26

You can try 2,4-D, I use it on my lawn to get rid of dandelions, it will not kill your grass. Here in USA, Michigan I try to buy mine from my local elevator, also roundup and Malathion for bugs. You get a lot more for your money. Here the 2,4-D is call base camp. I use it on weeds that roundup don't seem to kill.


Kitchen vinegar, a bit of table salt, a few drops of dish soap and spritz the leaves and center of plant. In a few days the weed will shrivel up and die. Dish soap helps mixture adhere to leaves. Best of luck to you 👍


We have six acres and two dogs that have to go running two or three times a day. When we go walking, we take a container of table salt with us. When we run into a thistle we pour about a spoonful of salt right in the middle of the plant. The next day it will be black in the middle and dying. Works on all prickers.

  • i will give this a try in my backyard next spring
    – Huangism
    Sep 23, 2019 at 12:56

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