Berberis is a genus of over 450 species of evergreen, semi-evergreen and deciduous shrubs from all over the world, preferring rocky soils in mountainous areas. Barberrys are commonly recognised for their sharp spiny stems.
Though Berberis are not recognised as a classic bonsai subject, there are many species that have small leaves that back bud easily, numerous small, showy flowers in a variety of colours and on mature trees can display beautiful bark markings.
Species suitable for bonsai include:
Berberis thunbergii varieties / Barberrys
Dense, rounded, deciduous shrub with ovate leaves to 3cm long, fresh green above and bluish-green underneath. Racemes of 2-5 yellow flowers are produced in Spring followed by glossy-red fruit to 8mm long in Autumn. Reaches heights of 1metre in its native Japan.
There are a number of varieties of B.thunbergii of which the red-leaved varieties are preferred, Berberis thunbergii Atropurpurea has dark purple-red foliage and vertically-striped bark. Variegated red-leaved varietes are generally far weaker and more susceptible to mildews than the plain red varieties.
Berberis darwinii / Barberry
Vigorous, evergreen Barberry reaching heights of upto 3metres in its native Chile and Argentina. Dark green leaves upto 3cm long are kept on the tree year round, while dark-orange flowers appear in Spring followed by glaucous-blue/black fruit appear in Autumn.
Berberis buxifolia / Barberry
Evergreen/ semi-evergreen Barberry that loses leaves only when exposed to low temperatures in Winter. Has leathery, dark-green leaves up to 2 cm long, dark orange-yellow flowers in Spring and dark purple fruit in Autumn.
Bonsai cultivation notes
Position Full sun or partial shade, protect from frosts below -5°C to avoid twig die-back.
Feeding Every two weeks
Repotting Every two-three years before bud break in Spring, use a standard soil mix.
Pruning Trim back after flowering unless fruits are required. For trees that require stronger growth, remove dead flowers to avoid wasting energy on fruit production. When pruned, Barberrys display unusual yellow inner stem, root and trunk colour.
Propagation Sow seed outside in early-Spring, root softwood cuttings of deciduous species in Summer, take semi-ripe cuttings of deciduous and evergreen species in Summer. Air-layer or ground layer in Autumn or Spring.
Pests and Diseases Powdery mildew can occasionally be a problem, aphids.
Styles Informal forms in single or multiple trunk groups. In small to medium sizes. Try to avoid stiff, angular trunk forms.
