Spring Annuals -- plants that grow from seed, flower, set seed, and die in a single year -- offer the gardener a vast palette. Because they bloom early and often, they are widely employed to provide summer and fall color in gardens whose spring depends on bulbs. Some require heat and full sun; others prosper in moist shade. Annuals also make superb container plants, either individually or in combination. Potted plants, dropped into holes in your spring garden, will quickly light up the neighborhood.