Digging up suckers with a peice of root is an easy way to propagate them. I would not recommend transplanting them now, as I have not had good success doing it in late summer/fall. If you dig up suckers next year when they start popping up, the transplants should take off quickly and get well established before the following winter.

You may be able to collect some root cuttings after the tops die back this fall, and hold them in a refrigerator in some lightly dampened sawdust or peat, then plant out next spring.