Annuals are flowering plants that complete their life cycles in a single growing period. This means they germinate, grow, flower and wither between one winter and the next. There are great differences in temperature, soil composition and humidity in the southern United States, and you'll have to choose annuals to plant based on the conditions of the area where you live [source: Kessler].
The annuals best suited to southern climates are, first of all, begonias, which have white, yellow, pink, red or orange flowers. They grow easily in fertile, well-drained soil. Wax begonias do well in cool to hot temperatures and can survive in shade or open sun. Tuberous begonias need more shade, water and fertilization, and don't do well in the heat of summer.
Cosmos are great for the beginning gardener because they're pretty hard to mess up. They grow rapidly and are particularly hardy as long as they get enough sun. "Yellow" cosmos have yellow, red or orange flowers and "pink" ones have pink, white and red flowers. Pink cosmos are not quite as hardy as yellow ones.
Marigolds have yellow, orange, gold and red flowers. They're hardy and easy to grow as long as you have a sunny, fertile, well-drained area for them; but they don't smell particularly good.
Pansies, which are red, purple, yellow and blue and have hybrids in white, orange, pink and black, are not as hardy as the above-mentioned flowers. They can't survive a southern summer, but they are more likely to make it through winter in warmer climates [source: PLANTanswers]. Pansies must be planted in the shade, in well-drained, acidic soil.
Petunias are available in pretty much any color you can imagine. They can grow in most soil and are fairly durable. Grandiflora petunias require more attention and can't survive the heat of the southern summer. Multifloras are more resilient and easier to maintain [Source: Scheper].