Most wisteria these days are grafted so digging up a piece of the root will only get you whatever the rootstock is. Is there a branch that has rooted itself to the ground? If not, create one. Choose a good healthy shoot that you can peg to the ground. Scratch the skin on the bottom side of the shoot on either side of each leaf node. Apply rooting hormone to the scratches and peg the branch to the ground at each node. Make sure the scratch spots are in good contact with the ground. The parent plant provides nutrients until the nodes can grow new plants and roots. Don't sever the new little plants from the parent plant until the nodes are well rooted and growing leaves.
Daisy
