How to Kill Milk Thistle


Many landowners and gardeners consider their battles with thistles some of the most challenging. Thistles types, such as milk thistle, grow virulently and invasively, making their ugly presence known. Thistles can be particularly obnoxious when they grow in pastures where livestock must feed. Because thistles usually grow among turf grass that you do not want to eradicate, use a selective herbicide to kill milk thistle. A selective herbicide will kill the broadleaf milk thistle and leave the grass unharmed. Choose a selective herbicide containing 2,4-D (a systemic herbicide).

Step 1

Mix the herbicide with water (2 tsp. herbicide to 2 quarts of cool water or 8 oz. herbicide to 6 gallons of cool water) in the bucket.

Step 2

Pour the herbicide mixture into the spray bottle, and seal the bottle tightly.

Step 3

Apply the herbicide mixture directly onto the undesired milk thistle, saturating the plant generously. Spray the herbicide onto each thistle directly.

Step 4

Monitor the condition of the milk thistles after you apply the herbicide. If you do not see the milk thistles visibly dying within one week, reapply the herbicide to stubborn milk thistle plants.

Tips and Warnings

  • Wear protective clothing when you are working with the herbicide chemicals. Cover your eyes with eye protection, wear closed-toe shoes and wear long sleeves and pants. If you are applying the selective herbicide to areas where livestock graze or where you will be harvesting hay, read product recommendations carefully to time your application properly.

Things You'll Need

  • Protective clothing
  • Selective herbicide
  • Bucket
  • Spray bottle


  • King County DNR: Milk Thistle

Who Can Help

  • Selective Weed Killer
Keywords: milk thistle grow, selective herbicide, kill milk thistle

About this Author

Kathryn Hatter is a 42-year-old veteran homeschool educator and regular contributor to Natural News. She is an accomplished gardener, seamstress, quilter, painter, cook, decorator, digital graphics creator and she enjoys technical and computer gadgets. She began writing for Internet publications in 2007. She is interested in natural health and hopes to continue her formal education in the health field (nursing) when family commitments will allow.