Unless you live in a zone 7 or higher, I wouldn't risk it. Containerized plants are far more vulnerable to winter cold damage than their counterparts planted in the ground. A very rough rule of thumb is that the plant in question should be hardy to at least 2 full zones lower than your own. Roots are the most cold sensitive part of a plant and are very easily damaged with the exposure a container receives from the very low ambient temperatures in winter.

I am newly transitioned to 7a so it sounds risky. Is there a hardier one?

Nope. Zone 5 is as cold as they willtolerate. And in that zone they tend to act like a dieback perennial rather than a shrub.

When they survive at all.

Mine in a cold frost-hollow act as semi-dieback depending on the winter here in z6. Ditto for crape myrtle.