Canada Thistle

August 4, 2021

Identification

Canada thistle is a perennial weed that spreads by an underground system of vertical and horizontal roots as well as by seed.
Plants are 3 to 5 feet tall, most of the time in patches (because of the roots) and have pink flowers that are bristly and ½ inch long and wide.
Seed can survive in the soil for up to 20 years. A single plant can develop a lateral root system with a 20 foot spread in one year.

Control

The best time of the year to spray Canada thistle is in September and October with a possible second application in the spring. An effective way to kill Canada thistle is herbicide. Clopyralid and Aminopyralid are two great active ingredients to spray on Canada thistle in pasture and range.
Another effective way is after grain harvest with a heavy dose of roundup. Due to its root system cultivation practices will only help spread the plants. There are several different products that have these active ingredients with different labeled use rates and application sites.

Contact Rocky Mountain Supply today and let us help you take care of you operation!