Berberis aquifolium, Oregon grape
An ornamental evergreen shrub with early spring scented flowers that grows well in shade. The roots can be used in a range of digestive and skin complaints.
scientific name Berberis aquifolium Pursh. (synonym Mahonia aquifolium)
family Berberidaceae
alternate names Holly-leaved barberry, Oregon holly
parts used Roots and bark
Ornamental early flowers of Oregon grape
Description
Oregon grape is an evergreen perennial growing up to 3-4m and spreading to 3m wide. It has leathery green pinnately compound leaves with sharp spiny teeth resembling holly. Early yellow flowers are produced in dense racemes from January onwards. The scented flowers are hermaphrodite and are pollinated by insects. The blue-black fruits ripen from August to September.
Habitat
Native to the western parts of North America especially in rich woods among rocks. Oregon grape has been widely grown in Europe for its ornamental value, and cultivated forms are regarded as invasive in some countries including Belgium and Germany. Oregon grape is considered a plant ‘to watch’ on the ‘species-at-risk’ in their native habitat.1
Related plants
The deciduous European barberry (B. vulgaris) is related and the bark, leaves and fruit can all be used for their berberine content.2 The lower growing shrub, creeping Oregon grape (B. nervosa), is also collected in North America.3 There are many varieties of Oregon grape developed for ornamental value of the flowers.
Oregon grape bush
Cultivation and harvest
Cultivation
The plant is hardy to USDA zone 5 (UK zone 5). It can grow in full shade or semi-shade or no shade. Oregon grape will thrive in a wide range of soils provided they are well drained. It prefers cold dry winters but does not do well in a windy situation. Our initial plantings at Holt Wood suffered from wind rock and staking is recommended until plants are established. Oregon grape is tolerant of pruning in spring, and can be cut back, coppiced or pollarded to suit the space available.
Pests and diseases
Resistant to honey fungus.
Seed propagation
Blue-black berries are harvested when ripe in the autumn, cleaned and sown in a cold frame and kept moist with a mulch. Fresh seed can germinate within six weeks. Stored seed should be cold stratified for three months. Prick out the seedlings when they are large enough to handle and grow them on in a cold frame for at least their first winter. Plant them out in late spring or early summer. Leaf buds or stem cuttings can be taken in the late autumn, and placed in pots in a cold frame. Division of suckers in spring.
Harvesting
The root is harvested late autumn to early spring, washed and then dried. Roots can be removed from one side of a well-established plant, which is then allowed to recover for several years. Alternatively, plan to harvest the whole plant and replace with a new one. The rootstock and root are knotty, and hard, with a yellow tinged wood covering. After harvest, clean, chop and spread in a thin layer, turning daily for up to a week.
Yellow colour indicates berberine in the roots of Oregon grape
Therapeutic use
Traditional
Oregon grape has been traditionally used by Native Americans to treat various ailments, including digestive problems and inflammatory skin conditions. Early settlers to the Montana region of North America used the berries to make jam.
Medicinal actions and uses
The root and root bark is alterative, antibacterial, cholagogue, diuretic, laxative and tonic. It is used to stimulate the kidney and gallbladder function and to treat catarrhal problems and skin disorders such as psoriasis. Internally, it can be used as a gargle for sore throats.
Clinical applications and research
Clinical trials have shown some effectiveness against atopic dermatitis and psoriasis.4 The anticancer properties of berberine have been the subject of continued research. In animal and in vitro studies, berbamine, an alkaloid constituent of Oregon grape, has shown antiproliferative activity against leukaemia cells so may help to promote recovery from chemotherapy and radiation therapy for cancer.5 Laboratory studies have indicated that Oregon grape may contain a specific multidrug resistance pump inhibitor named 5’-methoxyhydrocarpin which works to decrease bacterial resistance to antibiotics and antibacterial agents.6
Sample preparations and dosage
Used as a tincture 0.5-1ml three times daily.7 Use as an infusion (5-15g of chopped roots boiled in 500ml of water for 15 minutes) strained and cooled, and taken in spoonfuls throughout the day.
Constituents and commerce
Key constituents
Active constituents of Oregon grape include bisbenzyli-soquinolines, protoberberines and aporphine alkaloids.
Commerce
The Oregon grape is used primarily in floristry and in the horticultural trade as a landscaping plant.
Safety
Should not be used in large doses or for more than a few weeks, and should not be taken during pregnancy or breastfeeding due to the alkaloid content.
Other uses
Ornamental floristry. The fruit is very acidic and has large seeds but can be eaten raw or cooked. Traditionally barberries were made into a tart jelly.
1 See the Appendix 6(B) section on conservation and climate issues for details of species at risk.
2 Tabeshpour J, Imenshahidi M and Hosseinzadeh H. (2017) A review of the effects of Berberis vulgaris and its major component, berberine, in metabolic syndrome. Iran J Basic Med Sci 20: 557–568.
3 Harding AR. (1936) Ginseng and Other Medicinal Plants: A Book of Valuable Information for Growers as well as Collectors of Medicinal Roots, Barks, Leaves, etc., Columbus, OH: AR Harding.
4 Misík V, Bezáková L, Máleková L, et al. (1995) Lipoxygenase inhibition and anti-oxidant properties of protoberberine and aporphine alkaloids isolated from Mahonia aquifolium. Planta Med 61: 372-373.
5 Müller K, Ziereis K and Gawlik I. (1995) The antipsoriatic Mahonia aquifolium and its active constituents; II. Antiproliferative activity against cell growth of human keratinocytes. Planta Med 61: 74-75.
6 Tegos G, Stermitz F, Lomovskaya O, et al. (2002) Multidrug pump inhibitors uncover remarkable activity of plant antimicrobials. Antimicrob Agents Chemother 46: 3133-3141.
7 BHMA Scientific Committee (1983) pp40-41.