I just bought 3 varieties of EE all potted in 1 qt. containers from a local nursery. They were labeled Ruffles, Shiny Upright, and Black Magic. Now I've read on these forums that some grow from bulbs while others have runners. Do you know what these varieties grow from? Will these spread rapidly in my zone (6b Middle Tennessee)? Do they become invasive here? Will these overwinter here if I mulch them heavily? Thanks! I've seen these around always but just recently took an interest in them.