I think I discovered the problem I've been having with my dahlias. Not enough nitrogen. I did a soil test. Then once given a bit of nitrogen, they perked up. I gave one of my 'William Shakespeare 2000' roses some nitrogen, and did not give any to the other. The one I gave nitrogen is blooming, the other is not. Funny, given that everyone always says not to give much nitrogen to these plants, but obviously, that depends on the existing conditions.