If you have to take all or some of it. Plant right away and water-probably every other day-depending on the weather. Also put something near it that will shade if for next month or so. Best to move in the late fall or winter when dormant

Try to dig up as much of a root ball as possible. Have the new hole ready--a bit larger than the root ball--so you can immediately insert it into the new hole. Backfill and water slowly and very well--deep watering so that the entire rootball/roots get moistened. As the previous poster said, water often (but don't drown it) and give it some protection from direct sun for a couple weeks.

I have transplanted hydrangea several times in mid summer. Not the best time to do it, but it can be done. Just baby the hydrangea for a few weeks.

Kate

Thanks so much for the replies. My intentions were to wait a few weeks before attempting the transplant due to heat but not sure how long I can wait. I can auto water with drip or spray and have an excellent sun screen available.
I wasn't sure if I could divide the root system either. I don't want to kill what I take or what I leave even though the owner will cut it back to the ground each year with a mower.

Many people successfully divide a hydrangea but that does not mean everyone is "many people". Hydrangeas were just not 'designed' to be divided and cutting the brown with the necessary equipment can actually hurt the plant. Propagating from cuttings is safer but, like I said, some people have been able to divide them.

You can read both sides of the argument by doing a search for the word "divide". For more info on propagating, read the information on this link:

http://www.hydrangeashydrangeas.com/propagation.html

Luis

Thanks for the info and link Luis. I'll keep that one bookmarked. It's really nice to have access to a forum where there are so many knowledgeable folks to direct you to other sources for information. Thanks again.