What are the black marks that appear on my rose leaves? The leaves yellow after a while, and then fall off! What is happening?
Most likely, this is the typical description of a fungal disease called Blackspot. It infects the leaves of susceptible varieties of roses during periods of extended wet weather. Unfortunately, many of the roses we grow are susceptible to Blackspot to some degree, but as often as not, you may never see this disease in your roses. Cultural conditions play a major role in determining whether or not you will experience fungus diseases in your garden. Air circulation is important to keep disease spores from settling on the leaves. Proper nutrition is important also. Prolonged periods of wet weather are a major contributor to disease, which unfortunatley, we can’t do much about. In the springtime, many people opt to spray their roses with preventative chemicals which will control outbreaks of Blackspot. I prefer to use sanitation methods to keep disease at bay as much as possible, rather than turning to chemicals which have unhealthy impacts on garden fauna.
