University of Florida horticulture agent Gene McAvoy recommends planting warm-season flowers like zinnias in February and March for spring and summer flowers, and in September and October for fall blooms. Some gardeners take advantage of these maturity dates by replanting twice a year for maximum color.
Native Americans first domesticated the sunflower in 1000 B.C. and grew it as a food crop, along with beans, corn and squash. Contemporary American farmers still grow the sunflower, in part because the short time span required for the plant to mature. Only 90 to 100 days pass between planting a sunflower seed and the development of a fully mature and flowering adult plant.
Some spring-blooming flowers like the azalea flower from buds that form at the end of the previous growing season. These flowers may take from four months to a year or longer to mature.