Petunias are the flowers I have trouble cutting back. It's so hard to trim gangly plants if there's one last bud wanting to open, even though I know I'll have more blooms later if I do trim. Seems cruel to cut off a bud that's worked so hard to get to that point. At least with roses, you get a break between flushes, and all you are cutting are leaves.
Even as a young child, I would pick up trimmings and plant them.
