I would recommend trying to do root cuttings from this point until this coming fall. If none of the cuttings take over the summer months then I would take some dormant branches and try rooting them in potting soil (outside) during the winter. The success is higher during winter because there is no need to support leaf or bloom.
Then, when you have assured success with a cutting, then I would wait until the plant goes into a winter stasis (some roses never do go completely topside dormant), this would be during the Fall; I would then use your shovel to cut the rootball in place. Let the plant sit for a week or two with the rootball cut, sitting in the soil and place it stands now. As shocking as getting roots cut, it is equally as shocking to find yourself in a new spot; so cutting roots and then moving later is a wiser move. Then when the initial shock of having the roots cut is past two weeks simply pull the bush up and deliver it to its new spot. This will reduce all the trauma.
Several "Rules of Thumb" apply here. Winter dormancy is a perfect time to move older bushes, shrubs, and trees. A plant (trees and shrubs, and perennials) will create 90% of its newest root growth during the winter months, while not having to expend any energy or nutrition to the leafing process. So in essence, dormancy is not really asleep. Ensure you have a cutting that is rooted prior to moving the parent plant, and reduce any and all trauma as much as possible.
Wishing you luck. I didn't catch the full story on this rose. Was there a color or a name on it ? Any pictures?
Ron
