Every gardening and landscaping enthusiast should be familiar with the different U.S. Department of Agriculture plant hardiness zones. Dividing North America into zones based on the lowest potential winter temperatures, the USDA zones aid greatly in helping you decide if a particular species of plant is suitable for where you live. While zones such as zone 1 and zone 2 represent very cold climate areas where temperatures are frigid during winter, zones such as zones 7 through 10 are within states that experience much warmer winters.
USDA Zone 7
Zone 7 is the only continuous zone of these four, spanning the country. The minimum winter temperatures to expect in zone 7 are in the zero to 10 degree F range. The zone includes Long Island, coastal New Jersey, eastern Maryland, most of Virginia and North Carolina, western South Carolina, southern Tennessee, the northern halves of Georgia, Alabama and Mississippi and much of Arkansas. USDA zone 7 contains southern Oklahoma, a chunk of northern Texas, southern New Mexico, central Arizona, southern Utah and southern and western areas of Nevada. The zone extends into eastern California and west-central Oregon/Washington.
USDA Zone 8
Winters sometimes have temperatures in the 10 to 20 degrees F. range in USDA zone 8. The zone includes the southeastern tip of Virginia, coastal North Carolina, eastern South Carolina, Georgia's southern half, northern Florida (including the Panhandle), southern Alabama, southern Mississippi, most of Louisiana and extreme southern Arkansas. Much of the southern half of Texas falls within zone 8, as does central southern New Mexico, southeastern to northwestern Arizona and a chunk of southern Nevada. Zone 8 works into extreme southern Utah and covers a large area of eastern and central California. The western sections of Oregon and Washington are in zone 8.
USDA Zone 9
Expect the coldest temperatures within USDA zone 9 to reach between 20 and 30 degrees F. In Florida, zone 9 includes the central part of the Sunshine State. The zone snakes along the Louisiana coastal region and into Texas along the Gulf Coast. Southwestern Arizona, the most southerly portions of Nevada and southwestern California are in zone 9. Most of central and western California and the southwestern coastal region of Oregon are also in zone 9.
USDA Zone 10
Sections of the Hawaii, including Kauai and the big island of Hawaii, are in USDA zone 10, where the lowest temperatures are from 30 to 40 degrees F. in winter. Southern Florida, including cities such as Miami and Naples, are in zone 10. The zone includes a long stretch of the California coastal area and a very small part of southern, central Arizona. The only two states that have all four zones – zones 7 through 10 – present within their borders are California and Arizona.