United Kingdom 
white phlox for over fifty years in the front border,never failed, this year although they are now flowering the leaves are white, is this lack of water what do I do?
27 Jun, 2011
Answers
Warm, dry days with cool nights make mildew heaven!
28 Jun, 2011
is it white with a powdery coating? if yes then it is mildew and is down to the weather. you could spray with a fungicide.
27 Jun, 2011