Steve I find your carefully chronicled detailed observations very interesting and possibly useful in my garden as well. I don't have a seasonal stream but I do have a ditch that drains the driveway. I have planted mainly Earthkind roses in or right next to it and found that they did very well - except a couple that get some sort of leaf disease that seems rather worse than blackspot. Sea Foam is the worst. The leaves seem to burn up sudddenly. She spends most summers nearly nude. Last summer when it was extra hot and dry, blackspot was not a problem. I have never had mildew, that I know of anyway. I find that the old roses fight off disease better than the hybrid teas - even the disease resistant ones only live a few years for me, then gradually fade away cane by cane. I will be anxious to hear how your experiment continues.
