All need to be sprayed..................sounds like a fungus on the rose of sharon, need to cut that bad one out and bag & trash it............spray it with neem.............ants can't digest cornmeal, put some in a soup can pushed in a little flat to keep it dry.............put it behind the garage or shed..........way away from your house, spray around the house outside with spectracide for bugs. Rose of Sharon will self-seed.