Q&A for How to Control Black Spot on Roses

Baking soda with some non-bleach detergent sprayed on both sides of leaves. Add one box of baking soda to two gallons of water and add 1/3 cup baby shampoo and mix well before spraying every two weeks. Changes pH to kill and prevent fungal growth. Shampoo acts as coating agent to maintain alkaline pH. Respray after rain.

After watering, take a trowel, plunge it into the soil (away from roots) and pull it back to see how deep water has gotten. Too often, we think we've watered enough, but the water hasn't gotten down towhere the roots are.

Yes.

It seems that only the leaves are affected, as the fungus seems to be air-born. Cutting back woody stems with no leaves and cleaning up debris around the plant seems to help improve chances of survival.

Black spot can't survive very long in bare soil if it doesn't attach to a plant. The best defense is a thick layer of mulch, about 2-3 inches. Clean out all the foliage and debris, then spread the mulch to prevent the spores from getting to the plants. They'll then die on their own.