When to transplant a Rhododendron that has layered itself

My Rhododendron was just getting way to big - when I looked underneath I found it has layered itself.

I want to know when is the best time to cut the new plant off and replant it. Will fall work? This has obviously been layered sometime because the old branch/new trunk is a coupla inches in circumference.

Any advice would be greatly appreciated.

Then I can ask about the best way to prune it back to a mangeable size without it looking like fireworks sprouted!

Thanks in advance.

sookey66,
I'd wait until spring or post bloom time for any pruning operations. You don't want to promote new growth that might be subject to winter kill. Around here in Southern Maryland we do all this kind of work by the fourth of July.

raisedbedbob,
I sorta knew enough not to prune until after bloom or else I'd lose my great show. I am not trying just to encourage bloom but to resize a very large shrub.

What I really need to know is how far back to cut on the branch. I previously pruned my rhodo back by about six inches to a foot within the plant's surface (if you catch my drift) but when it regrew they extended out past the original plane of leaves - thus looking like fireworks or giant Scabiosas.

I have read somewhere that there is a ridge of some sort that you prune to, or at, but I'll be darned if I can identify it on my plant.

Have you successfully pruned your rhodo for reshaping/downsizing it?

Thanks so much for responding to my dilemma.

As you look along any given branch, you'll see little bumps or nubs. If you cut back to just above one of those, new branches will grow from that point. Generally multiple new branches will grow, so if you want your plant to be bushier that's the way to go (sounds like this is what happened to you in your previous pruning efforts). If you don't want all those new branches sprouting, what you should do instead is find an individual branch and follow it all the way back to the main trunk or the base of the plant, then cut it there. If you're trying to overall reduce the size of the shrub, I would cut about 1/4 of the oldest/longest branches back to the base this year, then repeat the process over the next several years. Some shrubs can handle severe pruning where you cut everything back at once, but I don't think Rhodies are one of them, so I'd recommend the gradual approach.

why not try cutting the newly layered branch in half and wait a season to see if damages the plant ? You can always cut it all the way through if you see no setback from the 1/2 cut.