Hi Rhododendron Chop - you can prune them straight after they've flowered. But if it's one of the really tough ponticum hybrids you can cut it almost to the ground, almost any time of year cos they're impossible to kill... Better be a bit more gentle though, if you're fond of it.
Gardeners' World Web User
28 Nov 2011 18:36
I don't want to destroy my rhodo but would like to know when it's safe to give them a good prune?