This species, from the Sonoran Desert in Baja California and Sonora, Mexico, is a shrub of cylindrical branches, and this form has green ones as opposed to the typical blue-green branches of this species. The beautiful red flowers are shoe-shaped, earning the name of the genus. We grow this species outside in Tucson, where it forms a large clump. It is damaged by frost below about 25F. These rooted cuttings are in one-gallon pots.