Acanthocalycium violaceum. (Syn: Acanthocalycium spiniflorum "violaceum") USDA: 8-10. Frost hardy to 25 F. Solitary to clumping growth, up to 2' tall, 6" diameter. Regular water summer; winter keep dry. Full sun to light shade. white to violet flowers. Origin: Banos de Zapallar /San Luis Argentina. HV 515