Frangula purshiana (DC.) A. Gray
Cascara Buckthorn, Cascara
Rhamnaceae (Buckthorn Family)
Synonym(s): Rhamnus purshiana
USDA Symbol: FRPU7
The bark is the source of the laxative drug, Cascara Sagrada, meaning "sacred bark" in Spanish. It is harvested commercially in Washington and Oregon by stripping bark from wild trees. When a tree is cut down, several sprouts grow from the stump. The berries are consumed by songbirds and bears, raccoons, and other mammals; hence this species is sometimes called "Bearberry."
From the Image Gallery
No images of this plant
Plant CharacteristicsDuration: Perennial
Habit: Shrub , Tree
Leaf Complexity: Simple
Fruit Type: Drupe
Size Notes: Up to about 35 feet tall.
Leaf: Dark Green
Fruit: Black, Blue
Bloom InformationBloom Color: White
Bloom Time: Mar , Apr , May , Jun , Jul
DistributionUSA: CA , ID , MT , OR , WA
Native Distribution: S. British Columbia south to N. California; also Rocky Mountain region south to N. Idaho and W. Montana; to 5000' (1524 m).
Native Habitat: Moist soils in open areas, along roadsides, and in understory of coniferous and mixed evergreen forests.
Growing ConditionsWater Use: Medium
Light Requirement: Shade
Soil Moisture: Moist
CaCO3 Tolerance: Low
Soil Description: Loam
BenefitUse Medicinal: The bark was boiled and the tea was drunk as a strong laxative by the Nuxalk, Coast Salish, Quileute, Nuu-chah-nulth, Keakwaka'wakw and other groups. Carscara has been scientifically substantiated as an addictive laxative.
Warning: POISONOUS PARTS: Berries. Low toxicity if eaten. Symptoms include nausea, vomiting, and diarrhea. Toxic Principle: Glycosides. (Poisonous Plants of N.C.)
Find Seed or Plants
View propagation protocol from Native Plants Network.
National Wetland Indicator Status
From the National Organizations DirectoryAccording to the species list provided by Affiliate Organizations, this plant is on display at the following locations:
Santa Barbara Botanic Garden - Santa Barbara, CA
Web ReferenceWebref 30 - Calflora (2018) Calflora
Webref 38 - Flora of North America (2019) Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
Webref 23 - Southwest Environmental Information Network (2009) SEINet - Arizona Chapter
Additional resourcesUSDA: Find Frangula purshiana in USDA Plants
FNA: Find Frangula purshiana in the Flora of North America (if available)
Google: Search Google for Frangula purshiana
MetadataRecord Modified: 2023-05-08
Research By: TWC Staff