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Posted on Thu, Jan 26, 2012 : 3 p.m.

Gardening with the new USDA Hardiness Zone Map takes recent warming trends into account

By Jim and Janice Leach


The new 2012 USDA Plant Hardiness Zone Map

Do you garden in the zone?

By which I mean, do you pay attention to the USDA Plant Hardiness Zone Map when planning your garden or making purchases at a nursery or garden center?

Among the guidelines created to help gardeners determine what plants will thrive in their climate is the gardening zone. You may have been aware that our area has until recently been labeled as Zone 5.

On Wednesday, however, the U.S. Department of Agriculture revealed a new climate zone guide that takes into account the northern warming trends and reconfigures the zones from the 1990 map. The 2012 guide is based on data gathered over the 30 year period from 1975 until 2005.

You can find the new interactive map here. Readers can enter their ZIP codes for more personalized information or view their state in a closer up view.

The map merely reflects the data that has been gathered. Whether these warming trends represent climate change or variations in weather is not a controversy that a map settles. Hardiness zone maps help gardeners determine what plants will grow best in their zone.

In short, some plants do grow well here in Michigan, while others do not. Zones are a short-cut for explaining the weather science behind why apple trees thrive in our state, but orange groves do not. When making garden plans or purchases, it makes the most sense to plant varieties and plants that stand a chance of thriving in your zone.

Have you witnessed these shifts in your own garden? Have warmer temperatures have made it possible to grow plants that were iffy for our area?

Janice and Jim Leach tend a backyard plot in downtown Ann Arbor, where they try to grow as many vegetables and other plants as possible. For the last four years, they've published gardening tips, photos and stories at their 20 minute Garden website.