Black spot on roses
Before I get started, I must say that I am very new to gardening, so please bear with me!
Well, I recently "inherited" several roses (not sure of the exact varieties) from my mother-in-law and, after winter, I had a peek and realized that almost every single one had black spot. I did some research and proceeded to cut away and dispose of all the diseased areas, thinking this would do the trick.
I went out there yesterday and noticed that it's back! Almost all of the plants have it again, so my question is, why is this?
Should I have been sterilizing my shears in between plants? I read that I should sterilize my tools, but only did so before pruning the first plant. Or did I miss something? Some diseased part that kept the fungus spreading? Any help would be greatly appreciated!
I want to make the roses something she would be proud of again!