Carol and Marie-Paule, if your interest in the USDA zoning system is to find areas in the US with a climate comparable to that in Denmark or Belgium, you are in for a disappointment. The USDA system is excellent for the areas for which it was developed, especially the heavily populated parts of the eastern United States and Canada. The more you move from that area, the less relevant it becomes. From what I have observed, people on the west coast of the United States do not use it much - they have better zoning systems developed in response to their local conditions. For the same reasons, the European zoning systems are different, too. The focus of the USDA system is on minimum winter temperature. As every experienced gardener knows, that is only one of the factors which determine the success or failure of plants in a given area. For instance, the dogwood Cornus florida, one of the most beautiful of eastern North American trees, grows wild as far north as zone 4 southern Canada (roughly as low as minus 35 C where winters are really winters). Yet it is difficult to grow well in the much milder English climate (in general, zone 8 in terms of winter temps) and evidently frequently suffers winter die-back. Yet dogwood also grows wild and flourishes in zone 8 of the southeastern United States (and it grows in the highlands of Mexico, too). The west coast dogwood, Cornus nuttallii, is generally a failure (actually, I know of no exceptions) here on the east coast in zone 7. USDA Zone 8 London, England, UK and USDA zone 8 Charleston, South Carolina, USA don't have much in common climatically except the zone 8 assignment. The aroid Amorphophallus konjac provides another example. If you had asked anyone fifty years ago (and some of us are old enough to remember those days), this plant would have been described as "sub-tropical". Adventurous gardeners here in zone 7 have been growing and flowering it outside for decades, and the trials, successful trials, continue to move northward. On the Alpine-L list, Panayoti Kelaidis today reported the survival of Amorphophallus konjac in Denver, Colorado, USA, zone 5. To paraphrase another contributor to this list, know your local conditions and don't be satisfied until you have killed a plant yourself several times. Jim McKenney Montgomery County, Maryland, USA, USDA zone 7, where three species of palm, Brugmansia, noisette roses but not Eucomis have grown outside for many years. essage----- From: pbs-bounces@lists.ibiblio.org [mailto:pbs-bounces@lists.ibiblio.org] On Behalf Of Carol Jensen Sent: Wednesday, July 13, 2005 3:03 PM To: Pacific Bulb Society; pbs Subject: Re: [pbs] Usda At 09:10 13-07-2005, Marie-Paule wrote: >Hello, >No, the temperature not always drop to minus 17dgr.C.The temperature is mostly between -6 and -13.but it not always freezes. >Thank You for the information, >Marie-Paule >_______________________________________________ It looks as though Marie-Paule and I are in the same zone (7). I would put us both in zone 8, since also in Denmark near the coast where I live, the winter temperatures are about 10C, enough to freeze the soil January and February and no more. Inland in Denmark is colder of course. Carol _______________________________________________ pbs mailing list pbs@lists.ibiblio.org http://www.pacificbulbsociety.org/list.php