How to get rid of black spots on roses?
Black Spots on Roses
Black spots are typically caused by the fungus called Black Spot. You will need to spray the rosebushes with a fungicide listed to control black spot fungus. If the black spots are significant, it may be necessary to spray them with a fungicide called Mancozeb which is available at Amazon.com as Mancozeb Flowable. If it is only a light bit of black spot spraying the roses with an earth friendly fungicide called Green Cure at the Cure Rate per the label should work to kill the fungus. Please note that once black spot attacks the foliage, the black spots on those leaves will not go away. However if the fungus has been properly killed, the new foliage will be free from the black spots.