Botanical Names: Mahonia (Berberis) aquifolia, M. nervosa, M. repens,
Family: Berberidaceae or Barberry
Common Names: Oregon Grape, dull Oregon grape, Mountain Holly
Habitat Dry to fairly moist open to closed forests at low to middle elevations. From California north to southern British Columbia and occasionally east into Idaho. David Douglas sent seeds back to England in the early 1800’s and as a result Oregon grape is grown as an ornamental all over the world.
Description Evergreen perennial shrub with waxy, prickly, holly like compound leaves. The leaves are alternate, with 9-19 leaflets and yellow flowers that bloom in the spring, in erect or drooping clusters, followed by edible but very tart blue/purple berries. The plants spread by rhizomes and often what appears as a large group of separate plants may actually be a web of connected plants: The sharp tipped rhizomes can radiate 10-20 feet outward and back from their original Grandmother plant forming a loose multilayered web with individual stems are possibly 150 years old. (Ryan Drum, Waldon Island, Washington).
Mahonia aquifolia is the Oregon state flower and the variety listed as medicine in the National Formulary (until 1935). Locally we see this leafy bush, 2-6 feet tall, mostly as a horticultural variety (outside the Manzanita Library, and Manzanita News and Espresso). M. aquifolia tolerates more sun than M. nervosa. Mahonia nervosa is a shorter broader shrub usually 2 to 3 feet tall, the variety most often seen in our coastal woods, usually a few miles away from the ocean, but also on the slopes of Neahkahnie Mountain. Both of these varieties are shade lovers, even more natively plentiful in the Willamette Valley and the Cascades than on the coast, with M. nervosa growing at higher elevations than M. aquifolia. Another variety, Mahonia repens is a one foot tall shrub, found in more open, drier habitats on the east side of the Cascades.
Cultivation: Herbalist Howie Brounstein reports good success replanting the tops including some rhizome while harvesting. Ryan Drum recommends vertically burying a 4-6 inch long stem tip with buds, an inch showing above the soil, tamped in well, with care to keep moist before and after planting. One gallon Mahonia spp. plants are available from local nurseries.
Parts Used: The thin bark and yellow-orange inner wood of the horizontal stem ( rhizome). Herbalist Michael Moore has a recipe for making an oil from the leaves.
Harvesting: Rhizomes are harvested from late autumn to early spring, when plant energy is most concentrated there. See Ryan Drums website for an excellent article with detailed information on respectful harvesting. http://www.ryandrum.com/devilsclub.htm
Dosage: Decoction: 1 teaspoon bark/cup of water. Or 4-6 oz of cut root and stem pieces in 3-4 pints of water. The medicine in Oregon grape decoctions becomes progressively stronger from prolonged steeping (24-72 hours) and repeated short daily reboiling (1-2 minutes)
Tincture: 1:5 root bark liquid extract: 10-60 drops 1-4 times per day. (Tilgner) Because berberine is better extracted by water than alcohol, tincture should be made with some water.
Bitter and astringent. From a Chinese perspective, Oregon grape clears heat and dries dampness.
Constituents: Oregon grape contains the alkaloid berberine, also found in other plants in the berberaceae family, for instance goldenseal. It also contains numerous additional isoquinoline alkaloids with good medicinal effects, berberine is the one to remember. See Michael Moore if you want to know them all.
Therapeutic Uses: This is a nice summary from Sharol Tilgner’s book: “Oregon grape root is used to astringe, stimulate and act as an antimicrobial in the gastrointestinal tract, respiratory tract and urinary tract. It is used for infectious conditions of the stomach, intestines, respiratory and urinary tract. It is also useful in liver congestion, chronic cholecystitis (gallbladder inflammation), skin conditions like psoriasis, dry eczema, acne and in some cases of rheumatism.” Judy Bluehorse teaches that Oregon grape has a particular affinity for the mouth and is specific for tooth and gum infections.
Cautions/Contraindications: Oregon grape is contraindicated during pregnancy due to the uterine stimulants contained in the plant, including berberine. (Sharol Tilgner) Use during pregnancy only under the care of a qualified midwife or other medical professional.
Also note that Oregon grape is on the United Plant Savers “to watch” list due to diminished habitats and the potential for overharvesting (http://www.unitedplantsavers.org/content.php/121-species-at-risk). Still, with respectful harvesting, it is a good substitute for its cousin goldenseal, which is much closer to being endangered, and on the “at risk” list. See Howie Brownstein’s article: (http://home.teleport.com/~howieb/treats/berberis.html
Rosemary Gladstar, editor: Planting the Future (Oregon grape chapter by Ryan Drum)
Michael Moore: Medicinal Plants of the Pacific West
Dr. Sharol Tilgner: Herbal Medicine from the Heart of the Earth
Thomas Avery Garran: Western Herbs According to Traditional Chinese Medicine
Pojar and Mackinnon: Plants of the Pacific Northwest Coast
Howie Brounstein: http://home.teleport.com/~howieb/treats/berberis.html
Ed Smith: Therapeutic Herb Manual (Herb Pharm)
2/5/2013 Vivi Tallman