Find a map of growing zones at the U.S. Department of Agriculture's website. The map is the standard map used by growers and gardeners to determine the plants most likely to thrive in their growing location.
When reading the map, keep in mind that hardiness zones are based on the average annual extreme minimum temperature during the past 30-year period, not the lowest temperature that has ever been recorded.
You can also find a map of growing zones at the Burpee website. Enter the ZIP code of the area you would like growing information for, or click on an area on the interactive map. Burpee's website also provides information on growing plants, including information on soil testing, nutritional information for vegetable and fruit plants, and a calendar to help you choose when to grow certain plants. The website also provides growing and gardening tips and advice.
Other environmental factors that contribute to a plant's ability to grow include soil type, wind, soil moisture, humidity and snow, in addition to factors such as pollution and winter sunshine. The way that plants are placed in the landscaped area, as well as how they are planted and their health and size, also contribute to their ability to grow.