On 8-Oct-12, at 6:34 PM, penstemon wrote: > To quote the article by Alun Rees (in The New Plantsman): "Plants > growing in > containers such as large pots, urns, and jardinieres appear less > resistant > to cold than those growing in soil nearby. This is because the growing > medium is cut off from the upward heat transfer from the ground One very cold winter here, potted plants on wire shelves in a hoophouse froze and died, but some potted plants left outside on the ground, close together, survived. They were in thin-walled regular plastic pots, and were on soil, not on concrete. Diane Whitehead Victoria, British Columbia, Canada cool mediterranean climate moderate dry summers, moderate rainy winters 68 cm rain (27 in)