When I come up with a solution to black spot I will be sure and post it. Some of my roses I think I could do with out spraying, some of my roses it does no good to spray, and some of my roses are actually harmed by spraying, even with the solution diluted down to an amount that is barley effective the leaves seem to suffer leaf burn. I try to pick off the really bad looking leaves as I go along weeding everyday, that way the weeds never get to be a problem and the roses don't get a chance to look really terrible, it only takes a few minutes to do both if done on a daily basis. Still there are a couple of my roses that the leaves never look good on this year, but I have yet to determine if it is black spot or a combination of several leaf diseases causing it. But I am coming more to the conclusion the best solution is to select roses that resist black spot, and here even the Double Knock Out series often suffer pretty bad from black spot, while a few others seldom have black spot at all. My neighbor has a Julia Child and it never gets treated at all, and it is doing really well.
