Prunus × cistena, commonly called purple-leaf sand cherry, is an upright deciduous shrub that typically grows 6-10’ tall and 5-8’ wide. It also may be trained as a small tree. It is most noted for its reddish purple foliage that retains good color throughout the summer. Prunus × cistena, commonly called purple-leaf sand cherry, is an upright deciduous shrub that typically grows 6-10’ tall and 5-8’ wide. It also may be trained as a small tree. It is most noted for its reddish purple foliage that retains good color throughout the summer.