Thanks for submitting the photos. That looks like an attack of Black Spot fungus. Once the leaves have the spots and damage, they will not leave that foliage even when it is killed. New foliage, after applications of a fungicide for treating black spot fungus is applied, should be free from the black spots. If not, they will need to be treated again. I have found a fungicide called Mancozeb to be the best at stopping this fungus. It does leave a yellow powdery residue on the foliage but that is part of how it works. Another fungicide that works well to get rid of black spot and other fungal diseases is Daconil® Fungicide. Read and follow the directions on the product label. I also recommend watering the infected rose bushes with some water that has "both" a product called Super Thrive and a Root Stimulator in it. Water them with a fresh batch of such water mix the next 5 to 6 times they need watering. This will help them build strength to fight fungal and other attacks off better.
Answered on June 8, 2021
Was this answer useful?00
Looking for more?
here are more questions about...Roses