In his latest “Hay & Forage Minute,” Bruce Anderson, University of Nebraska Extension forage agronomist, offers the following tips for controlling red cedar and musk thistle in pastures.
- Eastern red cedar. Anderson says Eastern red cedar trees reduce forage production, make animal handling difficult, and encourage pastures to shift from warm-season to cool-season grasses. Control can be achieved with herbicides, cutting or fire, but fire is the least expensive, when it can be used safely, he says.
Fire’s effectiveness declines as trees get large, however. Herbicides like Tordon 22K and Velpar applied directly to the soil beneath the tree work very well, but they’re time consuming and more expensive. Meanwhile, cutting is cheaper but even more time consuming, especially if cut trees need to be removed.
Recent Nebraska research shows a combination of control measures is best. A prescribed fire will kill many smaller trees and weaken or improve accessibility to larger trees. It also can be used periodically, maybe every 4-8 years, to eliminate new infestations.
After the prescribed burn, it’s usually best to wait a year before using herbicides or cutting to complete the job because some trees that appear to survive the fire will die. This minimizes the number of trees to cut or treat with herbicides.
- Musk thistle. The rosette stage of musk thistle is the ideal stage for controlling these plants in spring. If plants are sprayed while still in that rosette form, very few plants will send up flowering stalks for hand digging later. After flowering, the shovel is about the only method remaining to control thistles.
Several herbicides are effective and recommended for musk-thistle control. One of the most effective is Tordon 22K, but be careful as it can kill woody plants, including trees you might want to keep. A new herbicide, Milestone, also does an excellent job of controlling musk thistle. Both products also will help control other weeds that usually appear later in the season.
2,4-D also works very well, Anderson says, but using a little less 2,4-D and adding a small amount of dicamba to the mix will provide better control. Among other herbicides for musk-thistle control in pastures are Redeem, Grazon, Cimarron, Ally and Curtail.
– Bruce Anderson, Hay & Forage Minute