I'm intrigued by the idea of hybridizing spotted roses. I hope he does it.
I've always appreciated Knock Out as a flowering shrub because I can't think of any other landscape shrub that blooms all year, but I don't think much of Knock Out as a rose. It's just not as aesthetically pleasing to me as most other roses. As for its supposed disease resistance, I have one Knock Out in my garden and it gets as much black spot as any other rose in my garden, if not more.
