Few annual plants can match the heat and drought hardiness of alyssum. Alyssum flowers are so named for their lively fragrance and are members of the mustard family. Alyssum are useful in alpine rock gardens, borders, planters, hanging baskets and dry zones. They are small plants that may get 3 to 6 inches tall and produce clusters of tiny flowers in clumps. The blooms come in pink, salmon, purple, white and yellow. Flowers arise in June to October and can be encouraged to rebloom by cutting back spent flowers.