Will Cutting a Plumeless Thistle Stop Its Growth?

Control by Cutting

• Cutting the weed is a widely used mechanical control method for plumeless thistle. The weed is intolerant of regular cutting, digging or cultivation, according to the University of Nebraska Extension. Cutting the plants down to soil level during the early stages of growth prevents future growth of crown buds. Regrowth commonly occurs when plants are cut before the first terminal buds have bloomed.

Cultural Management

• Plumeless thistle is effectively controlled by making sure that the desired plants are growing vigorously, as the weed seedlings do not compete well with healthy plants in the invaded sites. Keep pastures well watered and fertilized. Graze pastures with horses, donkeys, sheep and goats in order to reduce plants like plumeless thistle that cattle do not eat. Monitor fields on a regular basis to control infestation in early stages.

Chemical Control

• The University of Nebraska Extension lists a number of chemicals that effectively control plumeless thistle. These include metsulfuron-methyl, clopyralid, 2,4-D, dicamba, picloram, aminopyralid or triclopyr. All herbicides are sold under different trade names. Herbicides are most effective when applied at proper times.

Application Time

• The weed is best controlled when treated during the active growth of plants at the seedlings or rosettes stage before flower and seed production. As the plant grows older than the rosette stage, the efficacy of chemicals continues to decrease. Once seeds are produced, extended treatments are required as the seed remain viable in the soil for a long period of time. Treatment is recommended in the fall rather than spring, since the plants build their root reserves in the fall and these are more readily affected by the chemicals in the fall than in spring. Using herbicides in the fall also minimizes risk of inadvertent damage to desired crops and other summer growing plants.