Cold hardiness of potted plants left outdoors in winter

Mon, 08 Oct 2012 18:34:28 PDT

>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

More information about the pbs mailing list