Cascara, Frangula purshiana

Cascara The Buckthorn Family–Rhamnaceae

Frangula purshiana (D.C.) Cooper

(FRANG-yoo-luh pursh-ee-ANN-uh)

Names: Frangula is considered by some to be a subgenus of the Buckthorn genus, Rhamnus. More widely known as Rhamnus purshiana, this species is also well known by the common name, Cascara sagrada, meaning sacred bark in Spanish. The bark is used medicinally as a very strong laxative. Supposedly from Chinook Jargon, old-timers called it Chittam or Chitticum (“shit come”) bark. This species is also sometimes referred to as Cascara Buckthorn, or Pursh’s Buckthorn.

Relationships: There are about 100 species of Buckthorns worldwide throughout the northern hemisphere and in the southern hemisphere in parts of Africa and South America. There are about 7 or 8 species of Frangula in North America.

Distribution of Frangula purshiana from USGS ( “Atlas of United States Trees” by Elbert L. Little, Jr. )

Distribution: Cascara occurs from British Columbia through northern California, mostly on the west side of the Cascades, but is also found eastward to northern Idaho and northwestern Montana.

Growth: Cascara grows to 15-36 feet (5-12m). It grows smaller and shrubbier in the southern part of its range. Its ecological habitat varies greatly; from fairly dry, rocky, southern aspects to somewhat shady areas, with rich humusy soils, bordering swamps or slow-moving streams. Wetland designation: FAC-, Facultative, it is equally likely to occur in wetlands or non-wetlands.

Diagnostic Characters: Cascara leaves are distinctive, similar to dogwood, but are alternately arranged. They are dark, glossy green, elliptical to oblong, with furrowed, parallel veins. The flowers are greenish-yellow in umbrella-shaped clusters. The fruits ripen to a purplish-black. The bitter bark is a smooth, silver gray.

In the Landscape: Attractive in all seasons, Cascara’s leaves are bright green in spring, turning dark and glossy in the summer. Yellow fall foliage is shed to reveal a picturesque branching pattern in winter. Cascara, however, does not adapt well to urban settings and is better in a woodland park or garden.

Phenology: Bloom Period: May-June. Fruits ripen August-September.

Propagation: Seeds are best sown in fall, 1 inch deep. Stored seed requires 1-3 months of cold stratification. Cuttings may be taken in late summer or fall of half-ripe to mature wood of the current year’s growth.

Use by People: As has already been mentioned, natives used Cascara bark tea as a laxative. It was introduced to modern medicine in 1877, and is still used in modern pharmaceuticals. Natives also used it on sores and swellings. The berries were eaten fresh in July and August. The bark and berries have also been used to make a yellow or green dye.

Use by Wildlife: Deer or other mammals may browse Cascara occasionally. The berries are attractive to birds, small mammals and raccoons. They are especially favored by Pileated Woodpeckers.

Links:

USDA Plants Database

Natural Resources Canada

Consortium of Pacific Northwest Herbaria

WTU Herbarium Image Collection, Plants of Washington, Burke Museum

E-Flora BC, Electronic Atlas of the Flora of British Columbia

Jepson Eflora, University of California

Calphotos

Ladybird Johnson Wildflower Center

USDA Forest Service-Fire Effects Information System

Virginia Tech ID Fact Sheet

Native Plants Network, Propagation Protocol Database

Plants for a Future Database

Native American Ethnobotany, University of Michigan, Dearborn

Pacific Dogwood The Dogwood Family–Cornaceae

Cornus nuttallii Audubon ex Torr. & A. Gray

(KOR-nus new-TAL-ee-eye)

Names: Pacific Dogwood is also known as Western Flowering Dogwood. It was named after Thomas Nuttall, an English botanist and zoologist.

Relationships: There are about 100 dogwood species worldwide found primarily in temperate regions. Three Dogwood trees and a couple of shrub species are found in the eastern or Midwestern United States. In our region, besides the Pacific Dogwood, we have a shrub, Red-Twig Dogwood, Cornus sericea, and a groundcover, Bunchberry, Cornus canadensis.

Distribution of Pacific Dogwood from USGS ( “Atlas of United States Trees” by Elbert L. Little, Jr. )

Distribution: Pacific Dogwood is found from southwest British Columbia, western Washington and Oregon and on the west slopes of the Californian mountain ranges. There is also a disjunctive population in northern Idaho.

Growth: Pacific Dogwood usually grows to about 20-30 feet (7-10m), but can grow to be 90 feet (30m). It may live to be 150 years old.

Habitat: Pacific Dogwood prefers moist, well-drained sites and is most often found as an understory tree in fairly open, mixed forests.

Typical parallel veining pattern of a dogwood leaf, turning red in fall.

Diagnostic Characters: The Pacific Dogwood leaves have the veining pattern typical of all dogwoods, where the nearly parallel secondary veins branch from the midvein and curve towards the tip as they near the leaf edge. Like most dogwoods, they have opposite leaf arrangement. The tiny, greenish, purple-tinged flowers are pressed into tight hemispheric clusters. These clusters are surrounded by 4-6 white (sometimes pink-tinged) bracts, creating a showy inflorescence with the appearance of one large flower. Each flower cluster develops into a bumpy ball of hard, red fruits in the fall.

In the Landscape: This attractive tree is often one of the most sought after native for gardens, but unfortunately larger specimens do not transplant well, and it is sometimes difficult to grow in containers. Small trees may sometimes be available in specialty nurseries but they are usually in short supply. Pacific Dogwood is also very susceptible to a fungus disease called Dogwood Anthracnose. This disease causes large brown blotches on the leaves and will also cause twig dieback. Many people are willing to accept this risk in order to enjoy the spectacular floral display this tree provides in the spring. Tall, flowering, Pacific Dogwood trees are most glorious when they are pressed up against the edge of a Douglas Fir forest. This tree’s beauty continues into other seasons with red berries, pinkish fall foliage, and an attractive branching pattern.

Phenology: Bloom Period: April-June, flowering may occur again in late summer. Fruit ripens-September to October.

Propagation: Seeds should be collected in fall, removed from their fleshy fruit covering and planted immediately into outdoor seed flats. Germination may take 18 months or more. Scarification and a warm stratification at 60ºF (15ºC) for 60 days followed by a cold stratification at 40ºF (4ºC) for 3-4 months may hasten germination. It is also possible to propagate by layering.

Use by People: Natives used the hard, dried wood for harpoon shafts and other implements. The wood has also been used to make thread spindles, golf club heads and piano keys.

Use by wildlife: Deer and elk will browse the leaves. Small mammals and birds such as grosbeaks, cedar waxwings, and woodpeckers eat the fruit. It is an impressive sight– Pileated Woodpeckers and Flickers in a Dogwood tree feasting on the berries!