A true annual is a plant that completes its life cycle in one year. They grow from seed, bloom, produce seeds, and die in one growing season. Annual plants provide beautiful colourful flowers from spring through fall. Some most famous annuals are petunias, marigolds, and zinnias. Plants that live for two years are called biennial plants and the plant that is supposed to live for three or more years is known as a perennial plant. Annuals produce more flowers because they have just one season to make enough seed to reproduce.