Powdery mildew can form on rose bushes. The mildew is light gray in color and usually forms on the upper surface of the leaves. Infected leaves may be distored and dry (crumple easily when touched).

To keep the mildew away from your roses, make sure that the plant has good air circulation and that it is well watered. Air circulation can be improved by pruning to open up the center of the bush. Be sure to prune away the infected areas of the bush.

Make sure your plany is well watered. Dry roots can lead to mildew.

If the mildew is caught early enough, a fungicide may help get rid of it entirely. But you should still take steps to keep the mildew from returning.