Mildew on Phlox

Asked October 15, 2014, 11:30 AM EDT

This summer my Phlox that I have had for 3 or 4 years was devestated by mildew, which I understand was a common occurance this year. My efforts to control it with fungicide were unsuccessful so I have removed all of my phlox. Can I replant new phlox next spring in the same location or is that soil contaminated? If it is contaminated, how do I treat it?

Kent County Delaware gardening mildew tall phlox phlox

1 Response

Sorry to hear about your experience with phlox this year, they can be so beautiful in the sunny summer garden. Phlox are known to get powdery mildew so when you get more read the label and look for mildew resistant varieties such as David and Delta snow (white ones) and Natascha and Robert Poore (both shades of Pink) and when grown well are wonderful in the garden. You asked if you should plant them in another space in you garden, that would be a good idea but good cultural practices is also important because powdery mildew is spread by spores blown on the wind and can come back. There is very little you can do to clean the spores out of the soil except rake up and remove the dead plants and fallen leaves. To grow strong plants be sure the soil is optimal for growing flowers (have a soil test) and the plants should be spaced far enough apart to allow for air to circulate. Sometimes the clumps become very thick with stems, so you should thin them out some. Mulch will keep the soil moist but they should be watered when there is no rain. Water from below because powdery mildew is encouraged by high humidity and wet leaves. a good web site toread about powdery mildew is from Clemson University www.mastergardeners.org/publications/powderyMildew.html