Berberis thunbergii Kobold - Barberry

Berberis thunbergii 'Kobold' is a dwarf variety of Japanese barberry appreciated for its naturally compact ball-shaped habit, requiring little pruning and particularly useful for creating dense ground cover or forming charming low borders. It is a deciduous shrub with many-branched, spiny stems and very decorative, small, glossy leaves that are brightly coloured in light green and then dark green in summer. In spring, it bears clusters of sweet yellow flowers striped with red, which are attractive to bees, and these flowers transform into small, bright red fruits in autumn. Before falling for winter, its small leaves temporarily turn yellow, sometimes tinged with red. It is not demanding and can be planted in full sun or partial shade in any well-drained soil.

The Berberis thunbergii, also known as Japanese barberry, is a shrub from the Berberidaceae family, native to Japan. It is characterized by a bushy, spreading, and low habit, and its foliage is deciduous or almost evergreen in mild climates. The colouration of its foliage intensifies under full sun. Hardy and resistant to temporary drought, it is a very easy shrub to grow in any well-drained soil.

The cultivar 'Kobold' was introduced in the Netherlands in 1960. It has a medium growth rate and reaches a height of 50cm (19.7in) with a spread of 80cm (31.5in). The branches of this variety are well-divided, beige to light brown in colour with small thorns. The bright foliage and dense ball-shaped habit are the main assets of this barberry. The shiny leaves are a few centimetres long and obovate (with the upper part of the leaf wider than the lower part). When they emerge, they have a bright green colour, and as they mature, they become almost dark green. In May-June, numerous clusters of 1 to 6 small flowers bloom on one-year-old branches. The bell-shaped flowers are 1cm (0.4in) long and a sweet yellow colour with red markings. They are highly nectar-rich and are followed in September-October by small, spherical, bright red fruits measuring 6 to 8mm (0.2 - 0.3in), which persist on the branches throughout part of the winter. The foliage turns yellow, sometimes tinged with red, before falling.

Japanese barberry is a very adaptable shrub in terms of soil, tolerating pruning well, but it clearly prefers sunny exposures. It is a shame to confine it to the role of a monochrome and anonymous defensive hedge shrub where its naturally graceful habit is completely lost. The small, glossy foliage of 'Kobold' deserves a prominent place in front of taller shrubs with pink flowers (Kolkwitzia, Abelia, Abeliophyllum distichum Roseum), red flowers (Japanese quince, roses, Weigela), or even yellow to orange flowers (Japanese kerria, Genista Lena Orange, Dropmore Scarlett honeysuckle). Its compact ball-shaped habit allows it to be used for decorative ground covers, even on slopes, and low green borders. It can also be paired with the red and purple foliage of other dwarf varieties of Berberis.