How to Kill Thistles


How To Kill Thistles Permanently

A garden can be an oasis of tranquillity and beauty, the perfect escape from the hustle and bustle of everyday life. But what happens when uninvited guests crash your party? If you're dealing with Thistles, you may be wondering how to permanently get rid of them

Key things to consider:

  • Thistles are a common weed that can grow in a variety of climates and soils. They grow in lawns and in bare soil, you may need different methods depending on where they are growing.
  • The fastest and least time consuming option is to use a systemic weed killer (recommend this one). But be careful and walsy remember to read the manufacturer's instructions.
  • If hand pulling or using manual methods ensure you wear protective gloves to avoid them stinging you.

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How to Identify Thistles

Thistles are easily identifiable, with their bright green leaves and purple flowers. They grow in a rosette-like shape, and have sharp spines on the leaves which can cause a nasty sting if you're not careful.

They can grow up to a metre in height and spread out to around a metre in width. 

Hand Pulling

One of the simplest and most effective methods of killing thistles organically is to hand pull them. This method is particularly suitable for small infestations or when dealing with isolated thistle plants.

However, before deciding to hand pull thistles, it's important to consider the following factors:

  • Root Depth: Thistles have deep taproots, and if the root system is not completely removed, the thistle may regrow. Ensure that you dig deep into the soil when pulling out the thistle, ensuring that you remove the entire root system.
  • Health and Safety: Hand pulling thistles can be physically demanding, especially when dealing with larger thistle plants. Consider your own physical capabilities and the potential strain on your body before choosing this method. Additionally, wear gloves to protect your hands from thistle spines.
  • Time and Effort: Hand pulling thistles requires time and effort, especially if you have a larger infestation. It may be more practical to use other methods for larger areas or when dealing with numerous thistle plants. 
  1. Use a garden tool: Such as a trowel, to dig deep into the soil and grasp the thistle at its base. 
  2. Gently pull upwards: Ensuring that you remove the entire root system. 
  3. Dispose of the thistle: In a bag or compost bin to prevent regrowth.


Another organic method for killing thistles is to smother them. This technique involves covering the thistles with a thick layer of mulch or cardboard, depriving them of sunlight and oxygen. 

  • Mulch or Covering Material: Select a thick layer of organic mulch or cardboard to completely cover the thistle plants. Ensure that the mulch or covering completely blocks out sunlight and oxygen to effectively kill the thistles. Avoid using materials that may contain weed seeds or have chemicals that could harm surrounding plants.
  • Duration: The length of time needed to smother thistles can vary depending on the thickness of the covering and the weather conditions. In general, it is recommended to leave the covering in place for several weeks to ensure thorough eradication of the thistles.
  • Revegetation Plan: After smothering thistles, it is important to have a plan for revegetation or replanting the affected area. Consider the type of plants or grasses you want to establish and ensure they are compatible with the conditions of your lawn or garden.

Boiling Water

Boiling water is a natural and readily available method for killing thistles, it may require several treatments (and may still not work) - do not use boiling hot water in your lawn!

  • Safety Measures: Boiling water can be dangerous if not handled carefully. Take precautions to protect yourself from burns by wearing appropriate clothing and using a kettle or pot with a spout to pour the boiling water. Be mindful of plants or desirable vegetation surrounding the thistles to prevent any unintended damage.
  • Thistle Locations: Boiling water may not be practical for large areas affected by thistles, as it is more suitable for targeted treatments. Assess the distribution of thistles and consider whether boiling water would be a feasible method for addressing the issue.
  • Reapplication: Depending on the resilience and regrowth capacity of the thistles, multiple applications of boiling water might be necessary. Monitor the treated area and reapply boiling water as needed until the thistles are eliminated.


Simply bring a pot of water to a rolling boil and carefully pour it directly onto the thistle plants. The hot water will scald the thistles, causing them to wither and die.

Vinegar Solution

Vinegar can be a powerful organic herbicide when used properly.

  • Create a solution by mixing equal parts white vinegar and water, along with a few drops of dish soap.
  • Transfer the solution to a spray bottle and apply it directly onto the thistle plants, ensuring thorough coverage.
  • The acetic acid in the vinegar will kill the thistles by drying out their foliage. Repeat the application as needed until the thistles are completely eradicated.

Vinegar is often touted as a homemade miracle weed killer, let me tell you, this is utter nonsense.

Vinegar can and does burn away the visible part of plants but it doesn't effect the roots.

Unless your thistles are small / weak, they will simply regrow.


Salt can be a useful tool for killing thistles, but caution must be exercised to prevent damage to other plants and soil.

  1. Mix a solution of water and salt, using approximately 1 part salt to 2 parts water.
  2. Apply this solution carefully to the thistle plants, ensuring that it does not come into contact with desirable plants or the surrounding soil.
  3. Repeat the application as necessary until the thistles are eliminated.

Salt is not selective, you will harm your grass is applying it to kill thistles in your lawn. It is a useful addition to your armory but mainly suited to small infestations of Thitstles.

Weed Killer

If the above methods do not provide satisfactory results, there are many strong weed killers available on the market that can easily kill thistles. 

For ease of use and the best results we recommend you use this weed killer. Follow the instructions provided by the manufacturer to ensure safe and effective use.

Remember to always spot treat the thistles, avoiding contact with desirable plants.

By using a strong weed killer, you can effectively kill thistles without worrying about them regrowing or spreading further across your garden.

Remember to be consistent and vigilant in your control efforts to prevent thistles from regrowing. With patience and persistence, you can enjoy a thistle-free lawn or garden.

Common questions:

Q: Will pulling thistles by hand kill them permanently?

A: Pulling thistles by hand can be an effective way to get rid of them, but it may not kill them permanently. Thistles have deep taproots that can regrow if even a small piece of the root remains in the ground. To ensure permanent removal, make sure to dig deep and remove the entire root system when pulling thistles by hand.

Q: Can I use vinegar or salt to kill thistles without harming other plants?

A: Vinegar and salt can be effective in killing thistles, but they can also harm other plants and soil if not used carefully. When applying vinegar or salt solutions, avoid getting them on desired vegetation or in the surrounding soil. Consider using barriers or shields to protect nearby plants when using these methods.

Q: Are there any natural predators that can help control thistle populations?

A: Yes, there are a few natural predators that can help control thistle populations. For example, the thistle head weevil and the thistle gall fly are insects that feed on thistle plants, reducing their ability to reproduce.

You can encourage these beneficial insects by creating habitats that attract them, such as wildflower meadows or native plant gardens.

Q: Can mowing the lawn help control thistles?

A: Mowing the lawn regularly can help control thistles to some extent. By keeping the lawn grass at a healthy length and preventing thistles from flowering and producing seeds, you can reduce their spread.

However, mowing alone may not eliminate thistles entirely, as they can still regrow from their taproots. Combining mowing with other organic control methods is recommended for best results.

Q: How long does it take to see results when using organic methods to kill thistles?

A: The time it takes to see results when using organic methods to kill thistles can vary depending on the size and maturity of the thistles, as well as the specific control method used.

In general, it may take several weeks to a couple of months to see noticeable effects. Consistency and patience are key when using organic methods, as thistles may require multiple applications for complete eradication.

Q: How can I prevent thistles from coming back?

A: To prevent thistles from coming back, it's important to address the underlying causes of their growth. Regularly inspect your lawn or garden for thistle seedlings and remove them promptly.

Improve soil quality by adding organic matter and maintaining healthy pH levels. Proper lawn care practices, such as regular mowing and overseeding, can also help prevent thistles from establishing. Additionally, keeping garden beds weed-free and avoiding overwatering can contribute to thistle prevention.

If you have any further questions please leave a comment below.

About the author 


Hey there, I am founder and editor in chief here at Good Grow. I guess I've always known I was going to be a gardener. I'm on a mission to share my UK based weed control & lawn care tips with you all. If you have any queries please post in the comments below.

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