The USDA has updated its plant hardiness zone map. Some areas of the country are in warmer zones, some not so much. The zone at sillydoggarden is about the same. Entering the Zip code initially gets us to 4B (-25 to -30), but looking a little deeper on the map puts us into 4A (-30 to -25). These are average annual minimum temperatures -- we've been known to have bouts of minus 40 degrees.
The new map probably won't change our approach to plant selection. We've always used the zone map as a guide and not as gospel. Pushing zones is a time-honored tradition -- you can't go crazy, but there are other factors to consider when deciding whether to choose a particular plant. Drainage, light and humidity are just a few things to think about. And, of course, you may have microclimates in your garden that make a big difference in survival.
