If you'd like to hard prune a healthy, well established, rhododendron, yes you can. You will probably lose flowering for the following year (even if you do prune right after flowering) by cutting back that far into old wood. Here, where their growing conditions are close to ideal, I have seen them cut to ground level only to resprout and completely renew themselves.

Or, you can follow the safest rule, and remove 1/3 of the plant over a three year period...both methods can sometimes be unsatisfactory though. If your rhododendron is growing well, cutting back hard because it no longer fits it space can be a very temporary fix...it may regain its size in just a few years. Do you know these are among the easiest of large shrubs to successfully move? A smaller growing variety that would need less mainteance could be planted in its place.

Another way to make them look less bulky and restore your view if they are growing close to the house is to prune along the back, and lower the height by selectively taking out branches...but as you can see you do have some options here. If you choose to move, or prune, mulch well with something organic following, and supply adequate water this season.

Here is a link that might be useful: where to make pruning cuts

Breezy, if you do decide to prune, just so you know what kind of time frame you are looking at, and will know when it's too early to panic, it normally takes an average of a month for dormant buds to begin to grow on smaller branches, and approx 10 weeks on older main stems.

I would not normally encourage fertilizing these low nutrient requirement shrubs, but...some will advise a one-time only application of nitrogen and phosphorus (i.e. 16-20-0) to stimulate new growth on a heavily pruned rhododendron that might otherwise be reluctant to break from old bare wood.

I'll probably be pruning rather than moving. I mean - these are already up to the 2nd story of the house.

And I do like them where they are - I'd just like them a little lower so I don't feel like they're closing in on me - lol!! Luckily, I don't think I'll need to butcher them too severely to accomplish what I need to do - I'd just like to do it as safely as possible for the plant.

A friend has asked me to help her on a job that includes pruning several large, neglected rhododendrons that must be at least 25 years old. She wants to do the job quickly, but I am having trouble doing fast work on such a daunting project.

It is difficult for me to lightly prune such a shrub only around the outside edges. I want to remove some of the main branches that are crossing and congested first, and then prune what is left. My friend is concerned with doing it this way because of the amount of time it takes, and the fact that there may be open spaces in the shrub that may seem "unbalanced" to some.

How much time do you think it should take to prune a large rhododendron that is about 10 feet high and 7 feet wide, that has been neglected for years?

Thank you

As above, safest is to plan the project out over 3 years, removing 1/3 of the branches at a time. Usually successful for healthy established rhododendrons is to do it all at once - although be prepared to lose most or all of the flowers for a year.

You can also prune it to look like a small tree rather than an out of control shrub. Start at the bottom inside and work up. This method works well where the shrub is growing up in front of a window. It allows you to see through it.

check out the next to last pic, pretty neat, kinda like a large bonsai plant

Here is a link that might be useful: pruning basics