Ferocactus gracilis - Red Barrel Cactus
Red Barrel Cactus is a spectacular desert plant with striking curved red spines. Mature specimens can grow to 3' tall, but they stay small enough for a windowsill for quite some time. They're easy to grow from seed.
Native to Baja California, Ferocactus gracilis needs sandy soil, full sun and very little water. Hardy to 22°F, it's happy outdoors in zones 9b to 11, and indoors in a sunny window anywhere else.
Ferocactus gracilis v. coloratus