Scotch thistle was added to the Sheridan County noxious weed list in 2009. This giant thistle was spreading quickly through many areas in Sheridan County. It grows 2-10 feet tall, and has pinkish purple blooms between June and August. The foliage of Scotch thistle is grayish-green. The wavy leaves of the rosette are as much as 20 inches long and 6 inches wide, which is an identification factor. The stems are winged and very spiny.
Scotch thistle is a biennial, which means it reproduces only be seeds. Each plant can produces as many as 500,000 seeds. So if you see a single plant growing in a pasture or gully, be sure to take care of the single plant, or you’ll have a problem for years to come. Scotch thistle grows in pasture, rangeland, roadsides, woody areas, waste areas, disturbed sites.
The EC-130 Guide for Weed Management in Nebraska recommends several herbicides for the control of Scotch thistle. Rosette stage will be the easiest and best time to control Scotch thistle. Digging Scotch thistle is an option if you only find a single plant or a few plants. One word of caution; if you chop a blooming Scotch thistle plant and leave it lying in the pasture, the plant has enough energy inside the stem to go ahead and produce viable seed.
Prevention is the best control measure for Scotch thistle. Prevent it from going to seed on your property. Prevent movement of the seed to other areas in Sheridan County.