CONTROLLING EXOTIC TEASEL

Mechanical Control:

Cutting, digging, and burning are recommended as the best solutions for control in natural areas. In small areas, rosettes can be dug up using a dandelion digger. Like dandelions, as much of the root as possible must be removed to prevent resprouting. Cutting with a sharp spade or shovel below the surface of the soil can be helpful, but the area should be checked later for resprouts. As an alternative, the stalks of flowering plants can be cut just before flowering. The plant should not reflower, but instead die at the end of the growing season. Cut flowering stalks should be removed from the natural area if the flowers have opened, because seeds can mature on the stem even after cutting. Cutting the flowering stalk before the full bud stage should be avoided because the plant will usually send up new flowering stalks. Cutting flowering stems may need to be repeated for several years to control teasel. Teasel in nearby areas should also be eliminated to prevent introduction of new seed.

Late spring burns can be useful in controlling teasel before it becomes dense. Burning should be employed with other methods to insure maximum control. Manual removal is assisted by burning the site in the spring so that the basal rosettes are visible amidst the blackened soil and grasses.

Chemical Control:

Triclopyr is dicot-specific and can be applied to foliage and stems at 2% active ingredient (a.i.) during the growing season, preferably before the plant has bolted (sent up a flowering stalk)--triclopyr is apparently the more effective of the two. Glyphosate is also effective when applied to foliage and stems at 12-2% a.i. before bolting, although it is non-selective. Herbicide can be applied after bolting, but seed development remains a risk. The rosettes of teasel remain green late into the fall, after most other plants have become dormant--application at this time reduces the risk of harming non-target species. Glyphosate may also be effective during the dormant season, providing the rosettes are photosynthesizing when glyphosate is applied.