Sharpen the blade of a long spade with a metal file, moving the file away from the handle repeatedly on both ends of the blade.
Plunge the spade into the ground at an inward angle 18 inches away from the base of the rosebush.
Repeat this process in a circle around the bush. This will sever the longer roots, encouraging the rosebush to grow new roots near the central root ball.
Repeat the root pruning process in autumn. This time dig a circle 12 inches around the rosebush's base.
Grab the bush at the base and lift it, shaking away as much soil as possible.
Have a partner continue to dig out the rosebush, being careful not to damage the new roots created in the summer.
Lift the rosebush completely out of the ground.
Trim canes to the length of the roots to minimize transplant shock. Remove all remaining leaves to give the roots time to regrow before they have to supply water for heavy photosynthesis.
Replant the bush in its new location.