I have a rhododenron that is desperately in need to some tlc (and pruning I think). We moved in to our current house a couple of years ago and soon had 6 leylandii taken down as they were casuing alot of shade. This has re-invigorated one of the rhododenrons but not the other. The one that is still struggling is approx 2 metres tall and at least 2 metres in diameter. It has produced one or two flowers this year. It has grown mainly in one direction, and is very woody. There branches are a tangled woody mess. In its current state it is an eyesore. What should I do?
Bit late now, but you can prune them down as low as a foot above the ground in spring. Try feeding with Miracleacid or some such ericaceous food.