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Berberidaceae FAMILY

Mahonia japonica

Mahonia japonica

Edibility
3/5
Medicinal
2/5

Safety & 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.

Cultivation Details

HabitEvergreen Shrub
Growth—

Mahonia japonica is a very cold tolerant plant. When fully dormant, it can tolerate temperatures down to about -20°c, though the young growth in spring is much more sensitive and can be damaged by temperatures around 0°c[1]. An easily grown shrub, it thrives in any good garden soil[2] including heavy clays. Prefers a semi-shaded woodland position in a damp, slightly acid to neutral humus-rich soil[3]. Plants can succeed under very heavy tree shade[1]. Succeeds in poor soils when the leaves will often become bright red, especially if the plant is in full sun. Plants are very tolerant of pruning and can be cut right back into old wood if they have outgrown their welcome[4]. This species is closely related to Mahonia bealei[2, 3]. It hybridizes freely with other members of the genus. The flowers have a delicious perfume[5]. The form 'Hiemalis' bears larger flower spikes which are almost as strongly scented as Lily of the Valley (Convallaria majalis)[5]. 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[6]. We have no data on susceptibility for this species[PFAF].

Propagation

Seed - best sown as soon as it is ripe in a cold frame[7]. It usually germinates in the spring[PFAF]. '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[PFAF]. 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[7]. 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[2]. Leaf cuttings in the autumn. Cite as: Temperate Plants Database, Ken Fern. temperate.theferns.info. 2026-02-21. <temperate.theferns.info/plant/Mahonia+japonica>

Pollinators

Insects

References

  1. [1]Shrubs. — Phillips. R. & Rix. M. · Pan Books · 1989 · ISBN 0-330-30258-2 ↩︎Excellent photographs and a terse description of 1,900 species and cultivars.
  2. [2]Trees and Shrubs Hardy in Great Britain. Vol 1 - 4 and Supplement. — Bean. W. · Murray · 1981 · ISBN - ↩︎A classic with a wealth of information on the plants, but poor on pictures.
  3. [3]The New RHS Dictionary of Gardening. 1992. — Huxley. A. · MacMillan Press · 1992 · ISBN 0-333-47494-5 ↩︎Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.
  4. [4]Ornamental Shrubs, Climbers and Bamboos. — Thomas. G. S. · Murray · 1992 · ISBN 0-7195-5043-2 ↩︎Contains a wide range of plants with a brief description, mainly of their ornamental value but also usually of cultivation details and varieties.
  5. [5]Scented Flora of the World. — Genders. R. · Robert Hale. London. · 1994 · ISBN 0-7090-5440-8 ↩︎An excellent, comprehensive book on scented plants giving a few other plant uses and brief cultivation details. There are no illustrations.
  6. [6]Flora of N. America — http://flora.huh.harvard.edu/fna/ ↩︎An on-line version of the flora with an excellent description of the plant including a brief mention of plant uses.
  7. [7]Propagation of Trees, Shrubs and Conifers. — Sheat. W. G. · MacMillan and Co · 1948 · ISBN - ↩︎A bit dated but a good book on propagation techniques with specific details for a wide range of plants.
  8. [8]Flora of China — Missouri Botanical Garden Press; St. Louis. · 1994 · http://flora.huh.harvard.edu/china/ ↩︎An excellent, comprehensive resource in 25 volumes. In addition to the botanical information the flora also gives basic information on habitat and some uses. An on-line version is also available.
  9. [9]A Barefoot Doctors Manual. — ? · Running Press; Philadelphica. · 1977 · ISBN 0-914294-92-X ↩︎A very readable herbal from China, combining some modern methods with traditional chinese methods.
  10. [10]Medicinal Plants of China — Duke. J. A. and Ayensu. E. S. · Reference Publications, Inc. · 1985 · ISBN 0-917256-20-4 ↩︎Details of over 1,200 medicinal plants of China and brief details of their uses. Often includes an analysis, or at least a list of constituents. Heavy going if you are not into the subject.
  11. [11]The medicinal uses of the genus Mahonia in traditional Chinese medicine: An ethnopharmacological, phytochemical and — Jian-Ming He, Qing Mu · 2016 · http://dx.doi.org/10.1016/j.jep.2015.09.013 · ISBN 0378-8741 ↩︎A review of the medicinal uses of the genus Mahonia in China.
  12. [12]Earth Medicine, Earth Food. — Weiner. M. A. · Ballantine Books · 1980 · ISBN 0-449-90589-6 ↩︎A nice book to read though it is difficult to look up individual plants since the book is divided into separate sections dealing with the different medicinal uses plus a section on edible plants. Common names are used instead of botanical.
  13. [PFAF]Plants for a Future — pfaf.org ↩︎