Q: We are building planters in a corner of our yard. I would like to use perennials that will be hassle free and come back each year. Is tall phlox a good choice?

A: Phlox is a beautiful plant but it can be ravaged by powdery mildew disease. No amount of maintenance can prevent it once the fungus is established in a bed of phlox. The best strategy is to only plant mildew-resistant phlox. Look for the cultivars ‘David’, ‘Robert Poore’ and ‘John Fanick’. There may be more varieties than this but these three appear on several lists of disease-resistant phlox. Don’t let the beauty of the flowers at the nursery seduce you; make sure the phlox you plant are proven to resist mildew.