Finally! The USDA Hardiness Zone Map Changes

When I teach certain plants, I often find myself qualifying their hardiness.  I'll say things like, "Well, when I was in college, we were taught that Crape Myrtle would never survive in NY.   It's considered a solid zone 7 plant.  Yet, more and more, we see it in Manhattan gardens and in the Hamptons."  This was perplexing because New York was considered Zone 6 until yesterday.

On January 25, the USDA introduced an updated hardiness zone map, showing an upward shift of average lowest temperatures and thus generally making each zone shift north.  For example, whereas New York was Zone 6, it is now marked as Zone 7. 

The map itself debuted in 1960, and was revised in 1965.  In 1990 the map was updated, using data from 1974-1986.  This revision actually caused zones to skew lower, as during those years winters were particularly colder.  The current edition includes data from 1976-2005, and thus should have better average temperatures reflected in the map. The map is also clickable- so you can view insets of your state.