We have dug up and moved such large rhodies with good success. One died but the recipient didn't water it!!!! Others have just been relocated on our property and they are doing fine. btw, when I relocated one it was quite leggy so I bucked it back to about 30 inches high and it is coming back much tighter and in a better shape. I pruned it severely the spring after I moved it, but I have pruned a few of them very hard and they have been fine in about 2 years.

Rhodies are quite easy to move and will adapt to the change very well (providing of course it does get watered in its new home!). They tend to have a pretty shallow but wide root system, so not difficult to pop out of place. Best if you already have a new home in mind for it before you remove, although I've recycled established rhodies from my garden and they have sat just in their rootballs for several weeks to a month or more before relocating. Just make sure to keep rootball damp if this the case. In a plant that large, the rootball will be wide and heavy - try sliding it out onto a tarp and then moving it that way. Several sets of hands may be necessary :-)

I've also had success moving Rhodies IF done in the fall or very early spring. It just gets too dry here the first summer when I've done it when the weather is nice for me....

Thanks for your advice everyone. I'm going to have to wait until early spring I think. I get these ideas about what I want to do, and unfortunately for my hustband, it's usually something I'm not able to do myself.

I remember reading somewhere... I found the info. Excerpt below, and link to full article included.

"1. If you have time to plan in advance, prune the shrubÂs roots. Thrust a blunt-nosed spade straight down in a circle around the shrub, about 60 centimetres (2') out from the crown. Expect to hear or feel some snapping of roots underground. This will stimulate the growth of fine hair roots and help to form a more compact root ball that is easier to lift and less likely to break."

Here is a link that might be useful: How to move a large shrub

Thought I posted yesterday, maybe I just hit the preview button and bialed out.

Anyhow, what's the trunk diameter at about 1 foot from the ground?

2"?

6"?

If you can list that, I may be able to give you an idea of how big the ball will be.

There can be a dramatic difference in rootballs between 10' tall Rhododendrons.

Maybe the difference between a 100 lb. ball and a 400 lb. ball.

We moved two of those beasties from my front yard and gave them to people who'd appreciate them (sorry, I didn't!). Both were about 5 ft high. Basically waited until November, then pruned them and dug'em up, then transplanted them the same day. Both have done very well and are much, much happier in their new homes. :)

I wouldn't bother with cutting roots in advance. Too many variables for it to be likely to produce improved results. You definitely don't want to cut roots, let new roots grow out from cut ends and then cut those off when cutting again later. That would just be plant torture.