No plants
survive ten degrees in a container that I know of in the general plant
trade. Maybe there are some Alpine plants, but they are very
specialized.

I've noticed that one person in my neighbourhood successfully overwintered
hostas in containers last year, just left out for the winter, and the air
temperatures here in winter sometimes go down to -40C. So hostas seem to be
very cold hardy! (I'm trying it myself this year. I sure hope it works.)