I had never heard of this plant so I looked it up on wikipedia.
https://en.wikipedia.org/wiki/...
"They easily succeed in USDA Zone 6 with only a moderate mulch of straw or leaves. These hardiness ratings only apply to plants in the ground with the idea of preventing the actual root system from being frozen. If potted, they should be placed in a frost-free location if winter temperatures go below freezing. The plant is generally considered hardy without a mulch if minimum winter temperatures do not go below 25 °F."
Maybe you can put some in the ground and some in a pot. Looks like you got a nice little treasure. Be sure to show us some pics in the spring