I am a little new to phlox. This is my 2nd year with Shortwood and Nicki, and I haven't experienced mildew with either so far. I also have purple flame and a couple of NOID tall pink & lavender that friends shared with me. I think that as long as you keep them thinned to 6-8 stalks, giving them plenty of air circulation and avoid overhead sprinklers (wet leaves), you can keep powdery mildew to a minimum.
