Canna are actually indigenous or originating from the Americas. They have been spread to all the continents after European explorers reached the Americas and began commercial trade and colonial expansion. Most Cannas you will find are not original wild species, but hybrids of many types, clumped under the species Canna x Generalis with a cultivar specification.

Wild Canna's range can be found in the Southeastern US from the Carolinas and across to Texas. Canna are typically, very hardy. However, my experience with them does not include a zone such as New Jersey and while they grow in places like the United Kingdom, it is known that parts of the United Kingdom are warm enough because of the Gulf Stream to grown palm trees.

But I can tell you that the Canna here survived a very bad hard freeze. They withered and browned during the freeze, but then came back up in the early Spring. The magic here is that Canna produce rhizomes or tuber roots which are very starch rich and are very much the reason for their hardiness. The plant stays 'alive' in the rhizome.

I suspect that your Canna will survive the winter outdoors, but they will wither and come back in the Spring. You might want to keep some in pots and put some out and take the ones in pots inside during the Winter, till you gain confidence.

The Canna Rhizomes spread out flat, just beneath the surface of the soil, so don't bury them too deeply. They may send down deep roots, but the rhizome itself is close to the surface, perhaps 1/2 to an 1 inch below the surface.

Good Luck.