I’ve always planted as though we’re in USDA Zone 8, although many of my master gardener friends have told me we’re in zone 7. Our garden does have a sheltered location. We probably have a microclimate since our property slopes to the south, providing our plants with protection from those cold north winter winds.
But what zone are we truly in? Drastic changes in average low temperatures over the last several years have caused many to believe the USDA Hardiness Zone map is out of date. The last update occurred in 1990. A new map was proposed in 2003, but rejected. The National Arbor Day Foundation decided to go ahead and update their map anyway, and it’s worth taking a look at. They used data from the National Oceanic and Atmospheric Administration to formulate the new map. According to them, the changes in average low temperatures have changed so much that planting zones would change by as much as two zones!
I’ve noticed for years that several of my "houseplants" return each summer in our shade garden. Among them are spider plant, split-leaf philodendron, and butterfly plant.
Well, anyway, according to the new Arbor Day Foundation hardiness zone map, we’re now in Zone 8!
You can take a look at the map yourself, by going to Arbor Day Foundation. This new information gives us many more plant choices for our garden!