Know Your Garden Zone

 

Most plants that are sold will have a zone rating on them. The zone rating tells you if that plant is likely to survive in your garden.  It’s important information and every gardener should know their garden zone.  A gardening zone is determined officially by the United States Department of Agriculture, but a few other places have developed their own zone charts. If you live in another country your Department of Agriculture may have published its own chart, although the USDA chart covers Canada.

 A zone chart divides the country into areas by the coldest winter temperatures they may experience and numbers them.  That’s called your winter hardiness zone for gardening.   There’s another USDA zone chart for heat hardiness but it is little used.  Each gardening zone may be further divided into part A and part B.  The colder the winter, the lower the number assigned to the zone.  In the US mainland area, we currently have zones three to eleven.

 Where to Find Your Gardening Zone

Where can you find this gardening zone map so that you can see what planting zone you are in?   Almost every garden catalog has a zone map somewhere in it.  Most garden reference books do too.  Here’s an interactive map you can go to; https://planthardiness.ars.usda.gov/

Some places devise their own gardening zone maps, such as the Arbor Day Foundation and Sunset Gardening Publications. Since most plant sellers use the USDA chart to rate the hardiness of their plants it’s probably best to look your gardening site on the official USDA zone map.

How to Use the Gardening Zone Map Information

The gardening zone chart is used so that consumers can know what perennial plants will survive the winter in their area.  Most plant labels and gardening catalogs will put the zone hardiness rating somewhere in the plant description.  When you choose plants for your garden choose plants that will grow in your zone or a lower numbered zone.

 If you are a gardener in zone five you will want to choose plants that are rated hardy to zone five, or lower.  (Zone three is about the coldest area of the mainland United States.)  A plant rated hardy to zone seven would probably not survive the winter in your garden.

While most plants that have been in the market for a while will be assigned pretty accurately to their gardening zone, new plants may be less accurately placed. When new plants are put on the market they will probably have been trialed in a number of places, but until thousands of gardeners are growing the plant, the information about their zone hardiness may be only a guess. When purchasing new plants, even new varieties of familiar garden plants, be aware that the zone hardiness may not be really accurate. 

How to Cheat a Gardening Zone

What if you live in gardening zone five and you really, really, want a plant that is listed hardy to zone six?  Sometimes you can get away with it. In every yard there are areas we call micro zones, areas where the climate is just a little different from the surrounding area.  It may be up against the south side of the house, in a courtyard, or in a sheltered pocket surrounded by heat holding rocks or cement. A zone six plant might survive there.

There are other gardening tricks to try too.  Deep mulching or a protective cover might do the trick.  Sometimes plants that mange to survive a few milder winters in the zone will acclimate enough to survive a harsher one. Start with small plants of the variety you want to try and plant them in the spring.  Only spend what you can afford to lose on the plant too.

And when you have been successful in getting a plant to grow in your gardening zone that wasn’t rated hardy for it, share the information with gardening friends and organizations.  That may inspire others in your zone to grow the plant and ultimately get the gardening zone rating changed.

Every gardener should learn what their gardening zone is. Most plants sold have a gardening zone recommendation. A gardening zone tells you what perennial plants will survive the winter where you live.