If you have ever read a gardening book or browsed through a seed catalog, you have likely seen a reference to "zones." Technically known as plant hardiness zones, they are sometimes called climate zones, planting zones, or gardening zones. The zone you live in determines what plants will thrive and when they should be planted.
Memphis, Tennessee is in climate Zone 7, technically both 7a and 7b, though you will rarely see a distinction between the two in books and catalogs.
The USDA Plant Hardiness Zones are determined by the average annual minimum winter temperature, each Zone represents a 10-degrees Fahrenheit section of minimum temperatures. There are 13 Zones, though most of the United States fits between Zones 3 and 10.
Zone 7 typically experiences the last frost-free date in the spring by April 15 and the last frost-free date in the fall on October 30, though those dates can vary up to two weeks. Memphis' Zone is very versatile, and most plant except the tropical plants can grow easily in the area.
Some of the best annual flowers for Zone 7 are marigolds, impatiens, snapdragons, geraniums, and sunflowers, Anyone who has visited the sunflower field at the Agricenter during the summer knows the latter to be true!
Some of the best perennial flowers for Zone 7 include black-eyed Susans, hostas, chrysanthemums, clematis, irises, peonies, and forget-me-not.
The Hardiness Zones are meant to be used as guidelines rather than hard and fast rules. Many factors are involved in a plant's success, including precipitation, shade level, plant genetics, soil quality, and more.
For additional information, check out the following resources:
Updated by Holly Whitfield November 2017