I have a very old Wisteria which had to be cut back to the roots to do major repairs to the wall behind. I thought we had killed it off but it has produced loads of whippy growth which is lying in an untidy mess on the ground. There is no longer a major stem but can I resurrect the wisteria just by taking some of the whippy bits and starting again tying them back to the wall. If so, how many should I tie back and are there any rules I should follow on this? Presumably the rest should just be cut off. Or is there a better way of doing this? Grateful for advice.