Q: Several years ago I planted beds of ‘Firewitch’ dianthus close to a bermudagrass lawn. Over the years the bermudagrass has infested the dianthus beds to the point of covering them up! Is there anything that I can use to remove the bermudagrass without killing the dianthus?
A: I once installed near my daylily bed a chameleon plant, ^Houttuynia cordata^, a plant I now regard as Satan’s favorite groundcover. The chameleon plant became so pestiferous that I had to dig up all of the daylilies and wash the soil from their roots so I could identify and cast out the ^Houttuynia^ roots. I put the daylilies in a different spot, then had the pleasure of spraying Roundup on the chameleon plant in the original bed. It took me a year of spraying, but the bad plant is finally banished. I recommend the same course of action with your dianthus. There is no selective herbicide that will kill bermudagrass and not hurt your flower.