Should I cut the plant back in the fall? And if so, how much should I cut back?

Welcome to NGA, @Dantra1 !

I'm not an expert on rhododendrons by any means, although I do have a couple of them... but I'm pretty sure you shouldn't cut them back in the fall because they make next year's flower buds pretty much right after they flower during the current year. In other words, you won't get any flowers in the spring if you trim them now.

I hope someone more knowledgeable will also answer your question.

http://www.rhododendron.org/v3...
Hope this helps.

Hi Sandy:
Spring is the recommended time to prune, and some blooms will be sacrificed. I usually clean up the Rhodys every spring, and if I do this yearly, the pruning is never very severe, and most blooms are saved.

I have had those years tho, when my Rhody's were neglected and turned into the Oversized Jolly Green Giant in the yard. Now my spring pruning will remove every bloom, so I elect to let the plant bloom and prune after.

Would it be possible for you to take a picture of the Rhody to see the height and shape of your plant. Pruning a 5 foot Rhody is not at all that similar to pruning a 10 or 12 foot Rhody. I spent my first few years of learning to prune these things, where I literally would prune the plant, by two feet all over, only to realize the plant still looked like Lurch, and had to start all over again.