Graythorn is native across a wide range of the Southwest, occurring from California east to Oklahoma and Texas, and south into Mexico. This durable landscape shrub grows slowly, forming a densely branched haven for birds and wildlife. The rigid branches are waxy, gray-green and tipped with spines. The flowers are insignificant, but blue-black berries produced in the summer provide some interest, as well as food for wildlife. Plant in full sun and well drained soils, Graythorn can handle reflected heat as well.