The Stella de Oro is the grande dame, with the longest blooming period of any daylily. It will bloom continuously from spring until frost. Its buttercup yellow, ruffled flowers bloom on 12-inch stems, with the plant reaching 24 inches. The Stella de Oro grows in USDA zones 3 to 9. While it prefers full sun, it can take partial shade. It is very drought tolerant and will tolerate almost any soil.