The new USDA hardiness map is available, reflecting the increase in temperatures since the last official map. http://planthardiness.ars.usda.gov/PHZMWeb/ Jerry
I am officially one zone warmer. This winter I would agree...next winter maybe a whole different story. I was really wanting to move south to where it was a little warmer, but evidently all I have to do is get old and the warm will move north.
They are a little slow getting the map brought up to date. My zone moved from 7b to 8a several years ago and I stopped buying plants that didn't have a range that went to at least zone 9...they just didn't survive very long.
I'll wait a couple more years . Now last year had actual temp of-40 without windchill.I think it's all the HOT air from VOTE FOR ME.
We are still 8b, and I'm glad. I'd hate to tell my plants that they have to pick up their little suitcases and move.
There is an article on the Horticulture Magazine website about the new map. The old one was developed in 1990 using information gathered over a 13 year period, from way fewer weather reporting stations than there are today and didn't take into account the way valleys, hills, rivers, lakes affect weather in each area. For this new one the information came from 30 years of reports, from many more reporting stations and the measurement methods included using algorithms that do take into account how terrain affects temperatures. So it's not so much that the weather has changed as it is the information gathering methods have improved to reflect what has been there all along.
