UPDATE: I am happy to report that the uprooted and damaged tree peony survived, despite a very brutal winter. I did not prune it back for winter, merely mulched it well and supported it with a post. Two weeks ago, I carefully cut away the dead upper growth to about 1 foot above ground. Within the past few days, it's showing fat pink buds all over the living growth, so I am pretty sure it will survive. It will probably be a few years before I see flowers again, but I'm just glad to have it! Thanks again to all the great advice and guidance. Youns guys are da best!