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Rhamnus purshiana

Cascara

At a Glance: Erect, tall shrub or small tree with alternate leaves and inconspicuous flower clusters.

Height: Up to 33 feet (10 meters).
Growth Form: Tree.
Stems: Thin, smooth, very bitter, silvery gray bark.
Leaves: Alternate (may seem opposite on young growth), egg-shaped to oblong, deciduous, dark glossy green, 6-12 cm (2.5-5 in) long, finely toothed, strongly pinnately veined in furrows, the surface washboardy.
Flowers: Small, with 5 sepals, 5 petals, and 5 stamens; 8-50 in stalked, umbrella-shaped clusters in the axils of leaves; primary color: greenish yellow; size: 3-4 mm long.
Flowering Period: April, May.
Fruits: Blue black to purplish-black berries, 5-8 mm across; edible.


Photo © Heidi Bohan

Sun/Shade Tolerance	Hydrology	Elevation Range
full sun > 80% mostly sunny 60%-80% partial sun and shade 40%- 60% mostly shady 60%-80% full shade > 80%	FAC- wet moist dry Wetland Indicator Status:	low elevation mid elevation sub-alpine high elevation

Soil Preferences
Favors similar soils as red alder and vine maple.
sandy soils gravelly soils clay soils muddy soils peaty soils	well drained soils shallow soils deep soils acidic soils basic soils	humic soils nutrient rich soils nutrient poor soils mineral soils organic soils

Habitat Preferences
Aquatic and Wetland: Ponds or lakes Shallow pools Sloughs Swales or wet ditches Seasonally inundated areas Marshes or swamps Aquatic bed wetlands Emergent wetlands Scrub-shrub wetlands Forested wetlands Bogs, fens Seeps, springs Shorelines and Riparian: Lake shores Bog margins Streams or rivers Stream or river banks Riparian corridors River bars Floodplains Bottomlands Alluvial areas	Saltwater Areas: In or near saltwater Mud flats Tidal areas Estuaries Saltmarshes Brackish water Seashores Coastal dunes or beaches Rocky or Gravelly Areas: Coastal bluffs Cliffs Rocky slopes Outcrops Crevices Glacial outwash Gullies Slide areas Sub-alpine and Alpine: Heaths Snow beds Tundra Avalanche tracks	Forests and Thickets: Forests and woods Open forests Coniferous forests Old growth forests Deciduous forests Mixed forests Nurse logs Forest edges, openings, or clearings Thickets Meadows and Fields: Pastures or fields Meadows or grassy areas Mossy areas Disturbed Areas: Roadsides Trailsides Logged sites Burned areas Disturbed sites

Wildlife Value

Berries

Seeds

Nectar for hummingbirds

Nectar for butterflies

Host for insect larvae

Thickets and shelter

Thorny or protective cover

Birds: Berries are eaten by grosbeaks, woodpeckers, grouse, band-tailed pigeons, mourning doves, jays, robins, and tanagers. It also attracts many insectivorous birds, including bushtits, kinglets, chickadees, flycatchers, and nuthatches.
Insects: Leaves and other plant parts are eaten by swallowtail, gray hairstreak, and other butterfly larvae.
Mammals: Black bears, foxes, coyotes, and raccoons eat the fruit.

Ethnobotanical Uses and Other Facts

Material Uses: The Nuu-chah-nulth made chisel handles of the wood. The Skagit boiled the bark to make a green dye for mountain goat wool.
Medicinal Uses: The bark was boiled and the tea was drunk as a strong laxative by the Nuxalk, Coast Salish, Quileute, Nuu-Chah-nulth, Kwakwakawakw and other groups. The bark was often allowed to age before use because the fresh bark is nauseating. The Coast Salish collected and dried the bark in strips in spring or summer. The next summer it was pounded and steeped in cold water, then boiled. Usually a handful of bark per quart of water was used. This plant was also used as a medicine for washing sores and swellings, and treating heart strain, internal strains and biliousness.
Name Info: "Purshiana" is named for the German Fred Pursh.
Interesting Facts: Used and held in high regard by the medical profession for many years. During WWII the bark was harvested in great quantities.

Suggested References

Alden, P., D. Paulson. 1998. National Audubon Society, Field Guide to the Pacific Northwest. Chanticleer Press. Page 110.
Brockman, F.C. 1968. A Guide to Field Identification: Trees of North America. Western Publishing Company. Page .
Cooke, S.S. A Field Guide to the Common Wetland Plants of Western Washington and Northwetern Oregon. Seattle Audubon Society and Washington Native Plant Society. Page 10.
Gunther, E. 1973. 2nd ed. Ethnobotany of Western Washington. University of Washington Press. Page 40.
Hickman, J.C., ed. 1993. The Jepson Manual: Higher Plants of California. University of California Press. Page 942.
Hitchcock, C.L., A. Cronquist. 1973. Vascular Plants of the Pacific Northwest. University of Washington Press. Page 290.
Jacobson A.L. 2001. Wild Plants of Greater Seattle. Published by author. Page 92.
Link, R. 1999. Landscaping for Wildlife in the Pacific Northwest. University of Washington Press. Page 250.
Lyons, C., W. Merilees. Trees and Shrubs to Know in Washington and British Columbia. Lone Pine Publishing. Page 96.
Pojar, J., A. Mackinnon. 1994. Plants of the Pacific Northwest Coast. Lone Pine Publishing. Page 90.
Turner, N.AJ. 1975. Food Plants of British Columbia Indians: part 1, Coastal Peoples. British Columbia Provincial Museum. Page 218.

The landscaping and restoration information provided on this page is taken from Starflower Foundation Image Herbarium. All photographs © Starflower Foundation unless otherwise noted.