My roses have cancer!!!

[Logan]

Going back to the early 80s I used to spray my roses for black spot with a systematic spray every two weeks, it would stop it but as @Mike Allen has said it doesn't cure it but it covered the leaves with a white powder, when I stopped it would come back so now i just leave it and take the fallen leaves up and mulch them in the spring after feeding them.

 

[DirtMechanic]

Going back to the early 80s I used to spray my roses for black spot with a systematic spray every two weeks, it would stop it but as @Mike Allen has said it doesn't cure it but it covered the leaves with a white powder, when I stopped it would come back so now i just leave it and take the fallen leaves up and mulch them in the spring after feeding them.

The clearys 3336 gives me a long run on the red cascade roses. It comes back but it takes a really long time. I have found a systemic that can be used around edibles (haha I found) that impacts a lot of spots but mainly is used on phytophthora(?) root rot and some fusariums. Its an ag product that is some form of potassium salts of phosporous acid. Sounds pleasant.

 

[Sheal]

Looking at this from another angle....your roses are in pots Zen Master. How often do you feed them? If they are watered regularly then any nutrients in the soil will be washed out. Roses are thirsty, hungry plants and must be fed regularly (especially in pots) to keep them in condition.