New Plant Hardiness Zone Map

New Plant Hardiness Zone Map from the USDA

The USDA has just released the new plant hardiness zone map. The new map is based on average minimum winter temperatures from 1976-2005.

The nice thing about the new map is that there is an interactive map feature available if you have a good internet connection. There are static maps available for view if you are still on a dial up connection.

The drawback to these maps is that they are based on average official temperatures. Right away I can see a problem with it. The new map shows me as being in zone 9a with winter temps of 20-25 degrees. The problem is that there are any number of winters in the past twenty years when the temperature has been as low as 15 degrees. And just 6 miles away Globe shows up as being zone 8b with average temps of 15-20 degrees.

Of course the map is just meant to be a guideline, you have to use your own common sense and knowledge of your own yard and micro climate. So I think I'll adopt the colder rating of 8b as I feel it more accurately reflects what is happening in my own yard.