Controlling Musk Thistle

Controlling Musk Thistle

April 18, 2008 

Favorable rains last fall and short pastures have created the right conditions for lots of thistles this spring.

The rosette growth form is the ideal stage for controlling these plants this spring. That means spray herbicides soon, while your musk thistle plants still are in the rosette stage, and few plants will send up flowering stalks for hand digging later.

Several herbicides are effective and recommended for musk thistle control. One of the most effective is Tordon 22K®, but be careful with Tordon since it also can kill woody plants, including trees you might want to keep. A new herbicide called Milestone® also does an excellent job of controlling musk thistle. Both Milestone and Tordon also will help control other weeds that usually appear later in the season.

2,4-D also works very well, but you will get better thistle control by using a little less 2,4-D and adding a small amount of dicamba to the mix.Other herbicides also can control musk thistles in pastures - like Redeem®, Grazon®, Cimarron®, Ally® and Curtail®. No matter which weed killer you use, though, be sure to read and follow label instructions, and be sure to spray on time.

All these herbicides will work for you this spring if you spray soon, before musk thistles bolt and send up flowering stalks. After flowering, though, the shovel is about the only method remaining to control thistles this year.

Bruce Anderson
Extension Forage Specialist