How to Cut Thistle After It Has Formed a Flower


Thistle is the common name for a number of species, some native, but an increasing number that are invasive, including many in the genus Cirsium, such as the bull thistle Cirsium vulgares. Once thistles flower, they rapidly go to seed and within a short time become highly invasive. They may even become the predominant species in fields and meadows, crowding out native and more valuable species. Therefore, despite their beauty, it is important to literally, nip them in the bud.

Step 1

Put on heavy gloves to work with thistles. They have sharp spines all over--from the flower head to the rosette on the ground--and you will hurt yourself if you do not wear gloves.

Step 2

Grasp the stem and gently pull the flower down where you can reach it (they can be quite tall), trying to avoid too much movement of the seed head if the bloom has matured and begun to disperse seeds. If the bloom is fresh or still a bud, and is not dropping seeds, skip the next step.

Step 3

Hold the flower stalk in one hand and use the other hand to spray water over the fluffy seed heads. (They are lightweight, and will blow away in the breeze like dandelion seeds. Wetting weighs them down so they cannot easily disperse.)

Step 4

Place a paper bag over the seed head and crimp it tightly around the stalk. (Tape to hold it shut at that point.)

Step 5

Use a knife or machete to cut the stalk below the paper bag.

Step 6

Cut the rest of the thistle to within a foot of the ground, then grasp the stalk and pull up the thistle root. (If it breaks you must dig it out with a shovel or trowel to kill the entire plant.)

Step 7

Burn the paper bag with the thistle head inside (preferably, in a wood stove or other contained fire where no seeds can escape to reseed).

Tips and Warnings

  • Resist the urge to allow thistles to bloom just because they are pretty. Do not fall prey to the idea that you can control them afterward. If a thistle is allowed to go to seed unchecked, you may be facing a lifetime of eradication effort.

Things You'll Need

  • Heavy gloves (leather recommended)
  • Spray bottle of tap water
  • Large paper bag
  • Masking tape
  • Sharp knife or machete


  • University of Missouri Extension: Thistles and Thistle-like Plants of Missouri

Who Can Help

  • University of Missouri Extension: Biological and Integrated Control of Musk Thistle in Missouri
  • University of Florida Extension: Thistle Control in Pastures
Keywords: cut thistle blooms, cutting down thistles, eradicate thistles, getting rid of thistles

About this Author

Deborah Stephenson is a freelance writer and artist, who brings over 25 years of both professional and life experience to her writings. Stephenson features a Bachelor of Arts in Anthropology from University of Arkansas at Fayetteville. She is an anthropologist & naturalist, and has published a field guide on Michigan's flora & fauna as well as numerous political and environmental articles.