A very spiny plant was dropped off at my office here in Woodland, CA that turned out to be Canada thistle, a noxious weed (Photo 1). This plant is commonly found in the Intermountain area in northern California where it has overtaken fields (Photo 2), but my first encounter here in the Sacramento Valley. It was found in row crop ground (Photo 3) and the landowner was having trouble controlling it. He cut it 6-in below ground, but it resprouted and grew back more shoots (Photo 4). He spot sprayed it with glyphosate and 2,4D, but the plants recovered (likely burned back the plants before good translocation happened, Photo 5).
Canada thistle is one really tough...
- Posted by: Gale Perez
The February 2019 issue of the Farm Advisor's Update by Tom Getts (Weed Ecology and Cropping Systems Advisor) is out.
- Winter Annual Weed Control in Alfalfa (Avoiding Crop Injury with Roundup)
- Purple Flowers, Pokey Leaves and Deep Roots: Canada Thistle Control Trial
- Update: Scotch Thistle Control in the Spring and Fall