This forum needs a good start, and black spot is probably the bane of every rose gardener.
I actually might be the wrong person to start this thread because I do nothing whatsoever to control black spot. Through the years I've tried various things, but they've never worked, and life's too short...
It seems to me that black spot is inevitable unless you live in a climate dry enough to be described as arid.
Yes, it makes the leaves ugly, but it can't kill the rose and it doesn't affect the blooms, and they're the important thing to me. Besides, the leaves eventually fall off and are replaced by beautiful new and healthy leaves.
I have about 1500 rose bushes, and almost all of them get black spot -- even the ones that aren't supposed to, such as Knockout. I have two roses that stand out from the rest as far as disease resistance is concerned: Playboy and Cinco de Mayo. There are others, but those two are conspicuously free of black spot because they're surrounded by other roses that are plagued by it.
I've also found that roses grafted onto Multiflora rootstock are generally more resistant to black spot than own-root roses and roses grafted onto Fortuniana or Dr. Huey rootstock.
Here's a picture of Playboy just to dress up the thread.
