I think Teresa has a good point- the tubers need to be protected from freezing.
Let me tell you this story. My friends put in an inground pool this year, and dismantled their pond. We went over there to check out the excavation- a giant mountain of dirt that the kids played on. They were giving me most of their pond plants when Tracey said "Hey don't we have that Lotus Karen gave us?" Sure enough, it had fallen out of it's pot and was buried in the mountain. So, Lowell pulled this thing out of the mountain with a yank and handed it to me.
I thought for sure that it was toast. It was a mess, but I didn't really need it back. I tossed it in a leaky pot and it sat on my driveway for two weeks in about a gallon of water. I finally went to drag it over to the compost, and it was growing!
So that Lotus had been buried in heavy clay, jumped on by kids, yanked out of the dirt like a vine, and left out to die in nothing but a small puddle. It bloomed better than my pampered ones!