USDA Plant Hardiness Zone Map

What are hardiness zones?

The U.S. Department of Agriculture's Plant Hardiness Zone Map divides the United States and Canada into 11 "hardiness zones" based on average annual minimum temperature (plus or minus a 10 degree Fahrenheit difference). The United States falls within Zones 2 through 10. These zones represent an area of winter hardiness for agriculture and landscape plants. (Generally speaking, it indicates what plants will survive winter weather in your community.)

Plant Hardiness Zones...

Zones 2-10 in the map have been subdivided into light- and dark-colored sections (a and b) that represent 5 F (2.8 C) differences within the 10 F (5.6 C) zone. (See map and map key below.)

The light color of each zone represents the colder section; the dark color, the warmer section. Zone 11 represents any area where the average annual minimum temperature is above 40 F (4.4 C).

The map shows 20 latitude and longitude lines. Areas above an arbitrary elevation are traditionally considered unsuitable for plant cropping and do not bear appropriate zone designations. There are also island zones that, because of elevation differences, are warmer or cooler than the surrounding areas and are given a different zone designation. Note that many large urban areas carry a warmer zone designation than the surrounding countryside.

North East U.S. Zone Map

Includes Connecticut, Delaware, District of Columbia, Illinois, Indiana, Kentucky, Maine, Maryland, Massachusetts, Michigan, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, Virginia, and West Virginia.

How to use the zone map...

Find your area on the map and find the corresponding "hardiness zone" number. (Most of Ohio falls in Zones 5 and 6.) When you shop for plant material at your local garden center, find out what the hardiness zones are for the plants you are interested in. You can find this information on plant tags or by asking certified nursery and landscape professionals working at your garden center.

If a range of zones (for example, "Zones 4-9", is indicated for a plant, that plant is known to be hardy in zones 4, 5, 6, 7, 8, and 9.) Suitable hardiness means a plant can be expected to grow in the zone's temperature extremes, as determined by the lowest average annual temperature. Keep in mind that local variations such as moisture, soil, winds, and other conditions might affect the viability of individual plants. Consult with your garden center to find the best plants for your situation.

The map-contains as much detail as possible, considering the vast amount of data on which it is based and its size. Click here to access the full USDA Zone Map. For more information about the USDA Plant Hardiness Zone Map, visit the U.S. National Arboretum website at www.usna.usda.gov.