I wish clay and glazed pots could withstand our winters but they eventually crumble and break. A friend of mine gave me several potted semps and one pot had a beautiful blue glaze. It took several years, but the pot came apart in layers. I never water these pots in the winter but there was enough moisture to break the pot. Same with unglazed terracotta pots. If the pots are new you can probably leave them in the pots for this winter and transplant next year. It took a few years before the pots fell apart.
Didn't I see a hypertufa pot in one of your pictures? Those survive the winters and the semps do really well in those. I like them better than plastic pots by far. Unfortunately they are expensive to buy. They aren't very expensive to make provided you plan on making 10 or more. I've made 10 big ones this year so far and am going to get some nice blue and green colorant later this week and then make some more.
