Annuals Re-Blooming

Annual flowers are called that because their life cycle is just one year or growing season. Some plants grown as annuals actually are perennials, but grown as annuals, either because they aren't hardy through winter, or because their bloom is less in succeeding seasons. Your dianthus is one that may come back for several years, but the marigolds and celosia won't. These latter two, however, can self seed in the garden and sprout new plants next year.