>Given that, I suspect that some geophytes native to central Texas were >probably not very hardy if they were grown in pots kept aboveground all >year round fully exposed to the elements, since they never experience being >completely (or partially) frozen when growing in the ground. 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 and frost penetrates the growing medium from the sides and possibly the base of the container as well as downwards. A small raised container can soon be frozen solid and remain so for several days whilst bulbs in soil nearby can be several degrees warmer." Bob Nold Denver, Colorado Z6