Certified GKH Gardening Expert
You have several options: I would recommend pouring boiling water on the areas where the bermuda grass was growing. Boiling water will kill whatever it comes in contact with. Alternatively, you could cover liriope clumps with cardboard boxes or use a gallon milk jug with the bottom cut off as a shield. Spray the grass with an herbicide during hot weather when the grass is actively growing. One application won't work, as it's going to take several. If a little herbicide touches the liriope, don't despair. It will only kill the little sprout, not the clump. Ortho Grass-B-Gon will kill grass and weeds but won't harm your liriope.