Rhamnus purshiana

Common Names

Cascara, Cascara Buckthorn, Cascara Sagrada, Chittam, Chitticum

Summary

Rhamnus purshiana, Cascara buckthorn or Cascara sagrada, is native to western North America from British Columbia to California, growing as a tall shrub or small tree with an upright to rounded canopy. It has elliptic to oblong alternate leaves with glossy green surfaces and strong venation, smooth gray bark, small greenish-yellow flowers, and blue-black to purplish-black berries, with autumn foliage that can turn yellow to orange-red.

Propagation is by seeds sown in fall at about 1 inch depth with cold stratification of 90–115 days, or by cuttings taken from half-ripe to mature current-year wood in late summer or fall; nursery-grown seedlings are best. In cultivation, it tolerates sun or shade and a range of soils, with a preference for moist, well-drained sites. Bark harvested for medicinal use as a laxative should be aged at least 12 months to mellow its purgative effect, with three-year-old bark often preferred; bark extract is used as a flavoring in soft drinks, baked goods, and ice cream, while the fleshy fruits attract wildlife.

Lifecycle

Perennial

Height

15-50 feet

Spread

19-20 feet

Hardiness Zones

Zones 3-9

Sunlight Requirements

Ideally Full Sun to Partial Shade.

Soil Type

Moist, well-drained soil

Soil Drainage

Moist soil

Soil pH

4-7, no single ideal pH, mildly acidic to mildly alkaline soils

Bloom Color

Greenish-yellow

Bloom Time

Spring

Foliage Color

Green, may turn yellow to orange/red in autumn

Fall Foliage Color

Yellow, sometimes with orange, red, and purple hues depending on sun exposure.

Leaf Lifecycle

Deciduous

Growth Rate

Slow

Seasons of Interest

Spring, Summer, Fall, and Winter

Propagation Methods

Seeds, Cuttings, Layering

Attracts Wildlife

Attracts wildlife, attracts bees