My second year plant of Prairie Celebration had a very prolific and prolonged flush of bloom this spring. I let hips form to see if I could raise any OP seedlings. However, it started to look a little stressed in mid-June so I cut it back a bit and removed a little over half the hips. It has produced one late-June bloom. I expect that if I'd removed all the spent flowers I'd have seen more.
I've used it as a pollen parent and hips are forming and have survived a very hot, dry June and early July.