Hi Kelli,
I have the choc. cosmos in my yard and has wintered over for about five years. The important thing is good drainage. It's much like a dahlia tuber so you could dig and store frost free over winter. They are not to expensive so if they don't return I just buy again in the spring. One year I got a bag of tubers at Costco but, that was a few years ago. I love the deep rich color hat goes well with most any thing.
