I bought some about 3-4 years ago, on sale, and planted them, thinking they would be an interesting annual, so left them in the ground to die, or live. Much to my surprise, they have lived and grown larger. They are in beds next to the house or porch, so a bit more sheltered than not, but some are in part shade and some sun - they don't seem to really care, with a slight tilt toward more sun. Mulch yours over the winter for the first year, and they SHOULD be fine - I can't guarantee it.

Since we will probably get more cold weather, and they aren't used to it, I would pot the tubers up for now - if you have room for more pots - keep them inside, or in the garage in a sunny/bright spot, and plant them out come warmer weather. You can also leave them in pots, as they don't seem to mind being slightly rootbound, but if in pots, they probably should come into a garage or basement for the winter, since pots will freeze more than the ground, being exposed on all sides. Burying the pots in leaves would also work, as long as you can keep mice, voles and squirrels out of the pots.

They don't seem to care if they are really wet or slightly dry, either. The common white ones will grow in standing water, but I think the species that the colored ones were hybridized from don't like it QUITE that wet.

If you get lots of cold weather, and your ground freezes consistently, I might dig half of them in the fall, and see if the others make it or not - if they do, leave them all out - it's one less chore in the fall to remember.

They are definitely hardy here in Raleigh, and are rated down to zone 7. I would do as Dibbit suggested and keep some in over the winter though just in case, as in Western NC they might be borderline. They like moist or slightly wet soil and light shade at the hottest part of the day, though if you are in the mountains they might not need it. I have the white ones with white spotted leaves and they grow wherever I put them, even dry heat, but flower best in light shade. I give them no special care. Some of the other ones may be pickier. Last year I added some red and yellow ones, but with the drought they may not have made it. They show up a little late when overwintered in the ground, so don't give up too soon if you try to overwinter them. Good luck. -Ais.

I grow them on the southside of Raleigh. They overwinter fine. Mine seem to make better healthier plants in the ground but bloom better in pots (could be my less-than-perfect yard).

I would pot them up and keep them as houseplants until summer, then plant them outside somewhere that you can keep them watered.

I'm in Charlotte, I have some that have done nicely for 3 years. They have overwintered fine, I just overmulch them well as mine are on the colder shady north side. I wonder if they will come back this year though, they were having a tough time last summer with the drought and heat.