How to Get Rid of Canada Thistle

Some varieties of thistle are toxic and some are not, such as the Canada thistle. It is a perennial plant that often survives attempts of eradication. The Canada thistle can grow, even when its roots are split. They like open soil areas that do not force them to complete with other plants, but flourish in crops, pastures and yards as well. It is difficult to get rid of Canada thistles because of their resilience, but if you use a combination of control methods, you will be able to successfully rid the plants from your property.

Things You'll Need

• Pesticides
• Tarp

Instructions

Gardening Methods

1. Mow large patches of thistle to deprive the roots of food during the winter months and to stop the flower from drying and dropping more seeds. Repeat the mowing process for a 3- to 4-week period during the flowering stage of their growth.

2. Cut the thistles when they reach 5 inches in length. Cut them again when new shoots form.

3. Pull the roots out during the early stages of growth to prevent the thistles from reaching flowering stages. Get as much of the roots as possible and try not to break the roots, which could result in multiple thistles growing.

4. Plant other plants that you find desirable to give the thistle competition to survive. Utilize grass seed or alfalfa seeds over top of the thistle. Plant these competitors when the thistle is still young and has not established itself yet.

Animal Methods

1. Allow your livestock to graze on the thistle, since they find the thistle a tasty treat and Canada thistle is non-toxic.

2. Introduce, or allow natural visitation of, insects that like thistle such as adult thistle-head weevil, thistle-stem gall fly, flower weevil, or stem-miming weevil. Be prepared for this method to take time since it may take time for them to establish themselves.

3. Use animals in conjunction with one another for best results.

Alternate Methods

1. Use an herbicide that includes glyphosate, dicamba or bromoxynil. Apply herbicides when the thistle is young.

2. Utilize burn crew professionals to burn thistles away in extreme infestations. Till up roots after the burn is complete.

3. Cover thistle plants with cardboard or tarps to keep them out of direct sunlight, which they need to survive.

Tips & Warnings

• Once you have killed the thistle, take measures to prevent them in the future by avoiding contaminated grass seed and mulch. Buy your gardening supplies from a trusted nursery.

References

• Canada Thistle
• How to Get Rid of Canada Thistle