Roses are beautiful, but these classic beauties are temperamental. They have a reputation of being difficult to maintain under the best conditions. And they're susceptible to a number of diseases, which makes growing them even tougher. If you find that your rose bush's leaves are wilting, you must act quickly or you are likely to lose the plant or even its neighbors to disease.
Rose bushes affected with canker develop sunken red or brown spots that eventually grow to envelop the entire rose cane. Once the cane is girdled by the canker, nutrients can no longer reach the leaves or blossoms, which will begin to wilt and eventually drop. To get rid of canker, prune the infected cane just below the canker.
In its initial stages, rust fungus covers the underside of rose bush leaves in a powdery, rust-colored coating. As the disease progresses, yellow or brown spots will appear on the surface of the leaves and they will begin to wilt before eventually dropping. Rust is best managed by pruning the affected leaves.
Rose Leaf Curl
Rose leaf curl causes new leaves to emerge smaller and less green than usual. As they grow, they appear wilted and curl downward. As the disease progresses, shoots will die back and the leaves will eventually drop. To control the disease, prune the affected leaves and treat the rose bush with a lime sulfur spray.