Toni: You could grow them as an annual ... or dig the tubers at the end of the season ... or I wonder if they'd overwinter just bringing the pot/container inside after they go dormant? I grow my Gloriosa in a container that stays outside year round. The past two winters we've seen many consecutive nights with temp's in the low to mid 20's and they weren't killed. They go dormant and I forget about them until they re-emerge in the spring. I know that y'all have very cold winters there in Colorado but maybe they could be overwintered in a basement. Maybe if the soil stays dry and not subjected to freezing temps for too long, they might be okay?
