New Plant Hardiness Zone Map

The release of the USDA’s new plant hardiness zone map the end of January primed the pump for my annual garden planning ritual. Like most avid gardeners, the months of January and February find me pouring over garden catalogs as I sip my tea, waiting for the snow to melt. This newest version of the USDA PHZM was developed by the USDA’s Agricultural Research Service and Oregon State University’s PRISM Climate Group and is now quite detailed, with a Global Information System component for Internet users. The new map isn’t just a guide for backyard gardeners, it will also help farmers when it comes to taking advantage of the shifting of zones to the north and the possibilities of growing new crops, and pest control. Of course the northward shifting of the zones due to warmer winter temperatures over the last thirty years has brought an onslaught of comments about climate change, but USDA officials insist that the new map makes no claims about global warming. Rather, they state that the shifting zone boundaries are a result of more sophisticated mapping, and that for the first time the PHZM takes into account the effects of elevation, large lakes, and whether a place is located in a valley or on top of a ridge.