Arequipa erectocylindrica (syn. Oreocereus hempelianus). USDA: 8-10. Hardy to 10° F for short periods. Full sun to light shade, needs protection in hottest desert gardens. Columnar cactus usually clustering, up to 18" tall. Moderate water spring and summer, no water in winter. Tubular red flowers. Attracts hummingbirds. Origin: Peru and Chile, Andes mountains above 5000 ft.