Gardening Zones

There are eleven gardening zones or plant hardiness zones in the United States and southern Canada. The USDA zone map gives a general indication of the minimum annual temperature for each zone so that you can find out which plants can be grown successfully in the area.

To find out the gardening zone for your area just enter your zip code in the box below.

You must remember that the zones are only a general guide and there are a number of other factors to consider when choosing plants. Within the zones there are variations in the microclimate of each area. This will depend on the location, for instance a garden in a city will have a higher average temperature than a garden out in the country.

Another factor is a change in the normal weather pattern. After several years of mild winters, regions may exhibit "zone creep," where plants seem to be fine that are not truly suited to even "normal" winters.

Cold temperatures for one night are not the same as cold temperatures for a period of weeks, even though the same low temperature is reached in both cases.

In areas with lots of snow cover, plants may survive normally deadly winter temperatures, due to the insulating effect of the snow.

At the other extreme there are plants which will suffer if there is too much heat. The American Horticultural Society has produced a Heat Zone map to help you find out how far south certain plants can be grown.

Although gardening zones are a good general guide to the plants that can be grown in the area, you would be well advised to seek local advice for information on a specific flower or shrub.