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Frangula purshiana

Frangula purshiana (DC.) A. Gray

Cascara Buckthorn, Cascara

Rhamnaceae (Buckthorn Family)

Synonym(s): Rhamnus purshiana

USDA Symbol: FRPU7

USDA Native Status: L48 (N), CAN (N)

Large shrub or small tree with short trunk and crown of many stout, upright branches.

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

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Plant Characteristics

Duration: 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 Information

Bloom Color: White
Bloom Time: Mar , Apr , May , Jun , Jul


USA: CA , ID , MT , OR , WA
Canada: BC
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 Conditions

Water Use: Medium
Light Requirement: Shade
Soil Moisture: Moist
CaCO3 Tolerance: Low
Soil Description: Loam


Use 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.)
Attracts: Birds

Find Seed or Plants

View propagation protocol from Native Plants Network.

National Wetland Indicator Status

This information is derived from the U.S. Army Corps of Engineers National Wetland Plant List, Version 3.1 (Lichvar, R.W. 2013. The National Wetland Plant List: 2013 wetland ratings. Phytoneuron 2013-49: 1-241). Click here for map of regions.

From the National Organizations Directory

According 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 Reference

Webref 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 resources

USDA: Find Frangula purshiana in USDA Plants
FNA: Find Frangula purshiana in the Flora of North America (if available)
Google: Search Google for Frangula purshiana


Record Modified: 2023-05-08
Research By: TWC Staff

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