V. bonariensis often survives in the ground with out any extra winter protection. It also seeds freely. So if you are desperate to save it then yes you can lift it. But I dont bother now.

Here in the south they pop up each year having self seeded about. I wouldn't want to be without them. I have read that they might need protection in the north through the winter and I would think a cold greenhouse would be adequate. when you have several you can leave a couple outside and see how they fare.