Van Zyverden 21413 is easy-to-grow Hippeastrum flower bulbs that will produce large, vibrant blooms. Enjoy these impressive flowers indoors for years to come. Plant them in pots indoors throughout most of North America. In USDA zones 9-12, they can actually be planted outside, as long as they are protected during freezing temperatures. They grow 18-30” tall and bloom in winter.