One of my plants has an abundance of dried brown leaves. Is this lack of water?
It is more likely that they got damaged back at the cane somehow or spider mites have gotten to them. Look for spider like webbing in and about the foliage. If found, that is likely spider mites. For spider mites be sure you use a miticide to control them, using regular insecticides will only kill off their natural enemies and the spider mite population will increase.