Please see Planttalk script 1529, Tall fescue is a wide-bladed clump grass commonly used in pastures. In a lawn, the textural difference of fescue from bluegrass is obvious because of its clumps. This interruption in uniformity makes us think of fescue as a weed.
Tall fescues have been the subject of much improvement and breeding. The resulting turf types make a good lawn if they comprise 100 percent of the lawn. However, when the pasture-type tall fescues invade a bluegrass lawn, you may note that the clumps are tougher and the lawn mower has difficulty cutting them. The tall fescue clumps often green up earlier in spring than the surrounding bluegrass. Clumps may become two feet in diameter, and may coalesce with other nearby clumps. When this occurs, there are several control options you can try.
For more information please see PlantTalk script 1529, Tall fescue as a weed in bluegrass lawns.
