Jamie: So far, all we have grown of the sinningias has been one clone of each. Our winters are usually fairly wet. This has been the wettest winter in recent memory and a cold of 10 degrees F. I'm sure good drainage helps, but these are really tough. I have no doubt that there are many more winter hardy species. As with many plants, they may also require good summer heat to produce enough sugars to account for this good winter hardiness. Tony Avent Plant Delights Nursery @ Juniper Level Botanic Garden 9241 Sauls Road Raleigh, NC 27603 USA Minimum Winter Temps 0-5 F Maximum Summer Temps 95-105F USDA Hardiness Zone 7b email tony@plantdelights.com website http://www.plantdel.com/ phone 919 772-4794 fax 919 772-4752 "I consider every plant hardy until I have killed it myself...at least three times" - Avent