John: Winter damage is quite a can of worms to open. Even nutrition and proper pH are factors in winter hardiness since they affect the electrical conductivity of a plants cell wall. A weak electrical charge in plant cells opens the plant to many types of damage in addition to cold. Plants do not feel a wind chill factor...this was a formula to describe the temperatures that humans "feel" on their skin. As Ken pointed out, wind and sun can desicate an evergreen plant when it causes water to evaporate from the leaves (possibly stems) while the roots are frozen and cannot take up water. Evergreens not exposed to wind or sun when the roots are frozen would be less likely to desicate. I don't have knowledge of containerized soils making a difference in potted plant hardiness. It is well documented that plant roots are far less hardy than bulbs or crowns. We usually figure that plants are about 25-30 degrees F less hardy when container grown. Some folks have developed insulated containers to avoid this problem. 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