Cascara Buckthorn TreeThe Cascara Buckthorn (R. Purshiana, DC.) grows from Puget Sound through California, and east to Colorado and Texas. It is extremely variable in size, adapting itself to different regions and climates with great facility.
In the canons of the Sierras it becomes a tree 40 feet high; on the exposed mountain sides and on the arid coast of California it dwindles to a prostrate shrub. Its elliptical leaves are usually evergreen or half evergreen; the fruits turn red on ripening, then black.
It is from the bark of this tree that the drug, Cascara Sagrada, is obtained. The species and its varieties are planted in shrubberies for their pretty foliage and bright fruits. Forms with deciduous leaves are hardy in Massachusetts gardens.