I believe there are different strains of blackspot in different locales. I grow mostly old garden roses now, and they resist blackspot admirably, but I have tried modern ones in the past. A lot of the roses Steve has found to be fairly free of disease have not done well here - notably New Dawn, Europeana, and even some Knock outs. Sunsprite, on the other hand is one I can grow here. (I've never been able to grow Iceberg either!) Anyway I hope you get some answers from rose growers near you. That would be the the most promising advice.
