Thistle weeds can take over a yard quickly and one thistle plant can produce up to 20,000 seeds. Thistle weeds will steal nutrients from other plants and choke them out as they spread in your lawn. In agricultural settings, thistle weeds threaten grazing grasses and wheat. Once thistle seeds contact the soil, they can remain viable for up to seven years. Removing the thistle from your yard may require different methods to kill them successfully.
Things You'll Need
- Lawn mower or shears
- Systemic herbicide
- Thistle head weevil
- Garbage bags
Put on gloves, long sleeves and pants. Cut the thistle plant at the soil level with a lawn mower or shears. Cut the weeds in the spring before the seeds develop. Continue to cut the thistle repeatedly as it regrows to weaken the roots to stop the weeds from growing.
Dig thistle weeds from the ground with a spade. Dig 12 inches away from the base of the thistle plant to create a circle around the base. Dig into the soil at an angle with a shovel and lift the plant from the soil. The root ball needs to remain attached to the plant. Remove any roots that remain in the ground with gloves so the weed does not grow in the same location again.
Spray a systemic herbicide to the thistle foliage in the spring after the buds appear or in the fall. The herbicide must contain clopyralid chlorsulfuron, glyphosate or dicamba. Allow the herbicide to remain on the thistle plant for up to 10 days. Repeat the application on plants that remain alive. Always follow the dosage instructions on the herbicide to apply it properly.
Introduce a thistle head weevil to the thistles in your yard. The weevil will eat the thistle and kill it. You can purchase these insects at most nurseries and specialty garden supply stores. The thistle head weevils must be purchased within your state from a distributor because you cannot transport them between states.
Collect the thistle debris in a garbage bag. Dispose of the thistle plant foliage immediately so that the seeds do not spread or blow across the lawn.
Tips & Warnings
- Introduce grazing animals like sheep or cattle to large areas to remove the thistle.
- National Sustainable Agriculture Information Service: Thistle Control Alternatives
- University of Minnesota Extension; Thistle Control; December 1999
- Purdue University Department of Botany: Control Practices for Canada Thistle
- University of Illinois Integrated Pest Management: The Bulletin Thistle Identification and Management; Aaron Hager et al.; April 2004
- Photo Credit Jupiterimages/Photos.com/Getty Images
How to Remove Weeds From the Yard Without Killing the Grass
Your lawn is being invaded by weeds. The problem is how to remove the weeds without killing the grass. By first improving...
How to Get Rid of Sow Thistle in My Yard
Sow thistles are vigorous weeds that resemble the common dandelion. While dandelions only have leaves at the base and feature one flower...
How to Kill Star Thistle
There are several types of thistle that are commonly called star thistle. Many of these are not native to the U.S. such...
How to Remove Clover From Lawn Grass
You can achieve a weed-free lawn, but you will need to treat the weeds and then the clover that seem to withstand...
How to Control Scotch Thistle
Sometimes called cotton or woolly thistle, Scotch thistle (Onopordum acanthium) is a weed. Although it prefers moist sites, it can thrive along...
How to Kill Thistles in Grass
Few weeds detract from an attractive carpet of green grass quite like tall, prickly thistles. These common, aggressive weeds can quickly take...
How to Remove Blade from Lawn Mower
Learn how to remove mower blade to prepare your lawn mower for winter in this free lawn maintenance video from a yard...