Mahonia dictyota, Mahonia amplectens, Mahonia pumila, and Mahonia wilcoxii are very similar, and the characters that separate them (height, glossiness and crispation of leaflets, and size and number of marginal teeth) are rather variable within the species. Mahonia piperiana also belongs to this group, although it is usually more distinct because of its thinner leaflets with more slender, more numerous marginal spines[].
The genus Mahonia is not universally accepted. Many botanists prefer to treat it as part of Berberis - as per the Flora of N. America[]. However, although they are very closely related (and there are some intergeneric hybrids), from the point of view of the gardener they are quite distinct genera. We are therefore following the treatment in the Flora of China[] which treats them as distinct. There is, however, at least one major revision (of the Chinese genera) currently (2016) in preparation and we will review the position of Mahonia once we have seen that revision[].

Common Name: Dwarf Barberry

General Information

Mahonia pumila is an evergreen shrub growing 10 - 40cm tall. The plant suckers at the base, producing a cluster of unbranched stems[].
The plant is harvested from the wild for local use as a food and a medicine. It is sometimes grown as an ornamental, where it can be used as a ground cover.

Known Hazards

All parts of the plant contain the alkaloid berberine - this is most concentrated in the roots, stems and inner bark, and least concentrated in the fruits. In small quantities berberine has a range of effective medicinal applications but, in excess, can cause vomiting, lowered blood pressure, reduced heart rate, lethargy, and other ill-effects.
The fruit of most, if not all, members of this genus are more or less edible and can be eaten in quantity since the levels of berberine in the fruit are very low.

Botanical References

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Range

South-western N. America - southern Oregon, California

Habitat

Mountains[]. Open woods and rocky areas; at elevations from 300 - 1,200 metres[].

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	0.30 m
Growth Rate	Slow
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

Mahonia pumila is hardy to about -15°c if growing in a sheltered position[].
An easily grown plant, it thrives in any good well-drained garden soil[], preferring one on the dryish side. Prefers a sunny position[], but also succeeds in the light shade of trees[].
Established plants sucker freely and form quite dense thickets[].
Resistant to honey fungus[].
Some Berberis/Mahonia species (especially Berberis vulgaris) harbour the black stem-rust fungus (Puccinia graminis Persoon). This is a major disease of wheat and barley crops and can spread from infected barberries to the grain crop. The sale or transport of susceptible or untested species of Berberis is illegal in the United States and Canada[]. This species is resistant to infection by the fungus[].

Edible Uses

Fruit - raw or cooked. We have seen no reports of edibility for this species, but it is certainly not poisonous. The fruit is likely to have an acid flavour and be suitable for making jams. jellies etc. The fruit is about 10mm in diameter[].

Medicinal

A decoction of the roots is used as a blood tonic and as a treatment for coughs[].


Mahonia species have a long history of medicinal usage, with several members of the genus being commonly used in traditional medicine and also in modern herbalism. They are employed in the treatment of a wide range of conditions and have, in particular, been demonstrated to exert good efficacy in the clinical treatment of dysentery, internal and external haemorrhage, acne vulgaris and chronic pharyngitis amongst other diseases. Phytochemical research into this genus has resulted in the identification of more than 150 chemical constituents, amongst which alkaloids are predominant. The isolated compounds and crude extracts have been shown to exhibit a wide spectrum of in vitro and in vivo pharmacological effects, including antimicrobial, anti-inflammatory, hepatoprotective, antioxidant, antimutagenic and analgesic properties[]
Berberine, an alkaloid that is universally present in the rhizomes and stems of Mahonia species, has been shown to have a marked antibacterial effect[] and is also used as a bitter tonic[]. Since it is not appreciably absorbed by the body, it can be used orally in the treatment of various enteric infections, especially bacterial dysentery[].
Berberine has also shown antitumour activity[].
The plant should not be used with Glycyrrhiza species (Liquorice) because this nullifies the effects of the berberine[].

Agroforestry Uses:

This species forms suckers freely and should make a good dense ground cover in a sunny position[].

Other Uses

A yellow dye is obtained from the inner bark of the stem and roots[, ]. It is green[].
Dark green, violet and dark blue-purple dyes are obtained from the fruit[].
A green dye is obtained from the leaves[].

Propagation

Seed - best sown as soon as it is ripe in a cold frame[]. It usually germinates in the spring[]. 'Green' seed (harvested when the embryo has fully developed but before the seed case has dried) should be sown as soon as it is harvested and germinates within 6 weeks[]. Stored seed should be sown as soon as possible in late winter or spring. 3 weeks cold stratification will improve its germination, which should take place in 3 - 6 months at 10°c. 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.
Division of suckers in spring[]. Whilst they can be placed direct into their permanent positions, better results are achieved if they are potted up and placed in a frame until established[].
Leaf cuttings in the autumn.