ph should be 5.5-6.5.........might be something eating it or a fungus.................clean off sharp clippers and clean again between cuts with alcohol or deluted bleach solution and cut off black flowers. when the sun passes over & the plant cools off mix 2 tablespoons dawn & 1 qt water and spray getting under the leaves...............I forgot to mention pick off any dark leaves...................spray under the plant on the ground with this. They are one of my favorite flowers. We are 5a and can only have them outside in the summer. They don't do well under 40 degrees. Happy summer.
