The leaves on my rose bush have turned yellow and are dropping off. What’s wrong?
If it’s the upper leaves that are mostly affected, it is probably a fungus disease called blackspot. A weekly application of a fungicide is vital. This will provide a “protective shield” over the new growth. A good spray program is like brushing your teeth. Preventing disease is the key. Once you have an established fungus (or cavity) it is a much more painful experience to get rid of it. In addition to routine fungicide applications, pick off all the affected leaves you see and dispose of them.
Blackspot fungus causes yellowing of rose leaves. Photo Credits: Theresa Friday, Santa Rosa County
If only the lower leaves are affected then it may be that the leaves are aging and the yellowing is sometimes triggered by heavy rains or excessive watering. Other reasons for yellow leaves include heavy infestation of spider mites or spray burn from frequent or improper spraying with insecticides.