Clumping fescue?

Its tall fescue........and since it grows above everything else, its fairly easy to wick Round up on the leaves, not harming the desirable grass. It might take a few hours if you have a lot of it- but it will be worth it !

Thank you. I did spray round up for lawns on it. It hurt it a little. Would you recommend regular Round up?

Ya, regular Round up is the only thing that will work. If you don't want to take the time to be careful rubbing Round up on each clump, you can go around with a spray bottle , or tank sprayer .......this will cause some over spray into desirable turf, but those spots can be re-seeded.