The traditional way is to prune them a foot or 2 from the ground. I don't see why you couldn't wait until just before active growth, though. I've done that, though not deliberately, before, and the plant was fine. It blooms on new wood which is why you prune. I'm not sure if it would produce as many blooms if you didn't prune or not, and the bush would probably get HUGE. One of mine gets to 6' as it is each summer.

I prune one too far(2 ft) and the other about 4 and the shorter one is gone,dead but the other one os over 7 seven feet . I did this before winter.
I will take pictures

I prune one too far(2 ft) and the other about 4 and the shorter one is gone,dead but the other one os over 7 seven feet . I did this before winter.
I will take pictures