Rough Bluegrass

Rough bluegrass (Poa trivialis) is a cool-season perennial grass weed that stands out as lime-green patches in fescue lawns during spring. It thrives in shaded, moist areas and goes dormant in summer heat, leaving thin bare spots where it once grew. Unlike Poa annua (annual bluegrass), Poa trivialis is perennial and spreads via stolons, making it persistent once established. In Middle Tennessee, it is most visible from March through May when its lighter color contrasts sharply with darker fescue. Control is difficult because no selective herbicide kills Poa trivialis without also damaging fescue — management strategies focus on cultural practices, maintaining dense fescue canopy, and spot treatment with non-selective herbicides when necessary.