I wager that all four would be extremely unhappy inside over the winter. The canna might be considered marginally hardy in your area, but should still be stored in a cool, dormant condition.

Be prepared to water your plants occasionally over the winter and protect them from severe freezes. The roots will be much more prone to damage growing in containers than if planted in the ground, but you can mitigate that by some protection.

ok thanks! What is the best way to protect them? I read everything from burlap sacks to making a cone of dried up leaves to wrapping them with blankets...

So, even though it says the plant is zone 5-7, I still have to protect them? I'm new to gardening and the zoning thing confuses me a bit...

thanks!!!

The root system is exposed to more temperature extremes than if planted solidly in the ground. So, winter protection can be essential to whether your plants come back after the winter or not.