Mahonia conferta Takeda is sometimes treated as a distinct species, but is probably not distinct[]. It is treated here as a synonym of Mahonia nalaulensis[].
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:

General Information

Mahonia napaulensis is an evergreen shrub or a small tree that can grow from 1 - 7 metres tall[].
The plant is harvested from the wild for local use as a food and a medicine. It is grown as an ornamental in gardens.

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

E. Asia - southwest China, Nepal, Bhutan, northwest India

Habitat

Dense wet oak and rhododendron forests; at elevations up to 2,900 metres[, ]. Forests, forest margins, thickets; at elevations from 1,200 - 3,000 metres[].

Properties

Edibility Rating
Medicinal Rating
Habit	Evergreen Shrub
Height	2.50 m
Pollinators	Insects
Cultivation Status	Ornamental, Wild

Cultivation Details

Mahonia napaulensis is only hardy in the milder regions of the temperate zone, under performing in areas where temperatures regularly fall below -10°c[]. In addition, the young growth in spring is very frost sensitive and can be damaged by temperatures around 0°c[].
An easily grown plant, it thrives in any good garden soil[]. Grows well in heavy clay soils. Prefers a semi-shaded woodland position in a damp slightly acid to neutral humus rich soil[]. Requires a position sheltered from cold or strong winds[].
Hybridizes freely with other members of this genus.
The flowers have a delicate sweet fragrance[].
At least one named variety has been developed for its ornamental value. 'Maharajah' appears to be hardier than the type species[].
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[]. We have no data on susceptibility for this species[].

Edible Uses

Fruit - raw or cooked[]. An acid flavour, but it is rather nice raw especially when added to muesli or porridge[]. Unfortunately, there is relatively little flesh and a lot of seeds[]. The fruit can also be dried and used as raisins[, , , ]. The purple, ovoid fruit is about 12mm long[, ].
The fruit is a very good source of micronutrients such as anthocyanins, phenols, flavonoids and vitamin C. They have a strong antioxidant activity and make an excellent, healthful addition to the diet[]

Medicinal

The fruits are strongly antioxidant, diuretic and demulcent[, , ]. They are used in the treatment of dysentery[].

A decoction of the bark is used as eye drops to treat inflammations of the eyes[].

A decoction of the root and stem is used in the treatment of dysentery, abscesses, conjunctival congestion, sore pain, periodontitis, acute pharyngolaryngitis, tuberculosis, and hemoptysis[].


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[].

Other Uses

A yellow dye is obtained from the stem and 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.
Cuttings of half ripe wood 15cm long, July in individual pots in a frame[].
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.