Our white wisteria is about ten years old and it thrived in the past. This and the last spring, just before the flowers developed, the central stems of some of the pendulum clusters looked as if something took a bite of it. The cluster wilted, the bite turned brown and the effected clusters died. Also one of the twining trunks is now completely dead. About 4 years ago I had an impulse to transfer the whole plant from a wooden to a plastic barrel. Could there be a connection perhaps? And at the same time there appear to be a couple of new shoots growing up from the soil next to the main trunks. Can someone, please, identify the problem; I hate to lose the plant.