Gardening in the South is a mixed blessing.The length of the growing season is one that northern gardeners envy, and a rich variety of tender and tropical plants can be used as perennials. On the other hand, soaring temperatures and high humidity can put lots of stress on plants, which often brings on a summer-long battle with pests and diseases. Additionally, clay soils and poor drainage are often negative factors toward achieving a successful garden. Before beginning your landscape project, consider the location of your planting beds. Most southern gardens need some protection from the hot afternoon sun; the high, open shade from mature pine trees is ideal. Try to choose an area that gets good air circulation and make sure to leave space between plants. Mildew and other diseases will be minimized if optimum air flow--hence, evaporation--is present. To counteract clay content in the soil, work in as much organic material (humus, peat, or composted leaves) as possible. This will aerate the soil and aid drainage. The design suggested here features perennials that meet the unique demands of southern gardening; it is best for lightly shaded areas.