"Calandiva" kalanchoe (Kalanchoe blossfeldiana "Calandiva"), a cultivar developed in the Netherlands, flowers for six full weeks in late winter and early spring. You can grow it outdoors in U.S. Department of Agriculture plant hardiness zones 10 through 12 or as a houseplant in colder climates. "Calandiva" gets along well with minimal care and will flower in the middle of winter -- as long as it's indoors -- with only minor manipulation.