Purple Fountain Grass and Pink Muhly Grass
If you grow grasses, you know that after a few years they tend to hollow out in the center. When this happens, the correct thing to do is divide. I also saw an article that said to use a drill in the soil and new grass will grow. I tried that with my Pink Muhly Grass Muhlengergia capillaris and it didn't work. I was too lazy to divide it this year so instead, I planted a Purple Fountain Grass Pennisetum setaceum 'Rubrum' in the hole. Sometimes you just have to break the rules!