Cascara Buckthorn

Rhamnus purshiana

Rhamnaceae

• Spokane Native
• Sun - Shade
• 20’-30' tall x 20'-30' wide
• Fruit: small red fruit turning black 
• Drought Tolerant: Moderate
• Evergreen: no
• Flower Color: greenish-white (April-June)
• Wildlife Value: Fruits eaten by birds and small mammals; hosts butterflies; provides cover

Cascara Buckthorn is a native deciduous small tree or large shrub growing 20-30 feet tall with a 20-foot spread. It naturally occurs on wooded slopes and in shady areas throughout the Northwest, thriving in partial to full shade. The tree prefers moist, well-drained soils but adapts to various conditions. It often grows as a multi-stemmed shrub or can be trained to a small tree form, making it versatile for different landscape needs.

The tree features large, prominently-veined elliptical leaves that are dark green through summer, creating a lush appearance in shaded areas. Small greenish-white flowers appear in spring in small clusters, though they're not particularly showy. By late summer, small berry-like fruits develop, changing from green to red and finally to purple-black when ripe. The smooth gray-brown bark and attractive branching structure provide visual interest year-round.

The berries provide food for birds and small mammals in late summer and fall. The tree serves as a host plant for various butterflies and offers good cover for wildlife. Historically, Cascara has significant ethnobotanical importance—the bark was (and still is) harvested commercially for medicinal purposes by Indigenous peoples and later settlers. The name 'cascara' means 'bark' in Spanish, reflecting this traditional use. However, the berries should not be consumed by humans as they can cause digestive upset.

Cascara Buckthorn excels in woodland gardens, shaded borders, and naturalized areas where it provides valuable understory structure. It's particularly useful for establishing native plant communities and restoration projects. The tree works well with other shade-tolerant natives like Oceanspray, Red-osier Dogwood, Nootka Rose, Blue Elderberry, and various woodland wildflowers. Its ability to thrive in shade makes it perfect for filling the understory beneath larger trees like Ponderosa Pine or Douglas-fir.  Its combination of ornamental bark, attractive summer fruit, and strong wildlife value make it a rewarding and underused choice for Spokane-area landscapes.