Berberis (barberry) is a genus of ornamental, evergreen or deciduous shrubs that includes some 400 species, the majority of which come from the temperate zones of East Asia, the remaining from North and South America.
Some botanists maintain that the North American species and in particular, the California species, should be classified as either a distinct genus or as Mahonia because their pinnate leaves and spineless branches differ markedly from true barberries. However, other leading botanists have recently ruled that the California species should remain in the genus Berberis.
No matter how they are classified, barberries’ pale yellow-to-orange flowers, waxy red-to-purple berries, and dazzling foliage covering the full spectrum of autumn colors and spring greens make them one of our most beautiful landscape shrubs. Ranging in size from compact to tall, they serve as striking specimens, an attractive medium-sized loose or sheared hedge, or a tall, sturdy screen. The wicked spines along the stems are a constant deterrent to deer, cattle, and other trespassers.
Barberries are easily cultivated. They thrive in sun or shade, but their beautiful fall colors and berries are more prominent with full sun. Many species can endure extremes in temperature and grow in almost any soil, so long as it is not water- logged. All are durable, disease resistant plants, rarely visited by cabbage looper caterpillars, which can be picked or hosed off or given an application of BT (Bacillus thuringiensis).
Shrubs are generally drought tolerant, needing only a minimum of water during a hot, dry summer. They require little maintenance, save for a light pruning to remove wayward branches in early summer after bloom. In especially poor soils, plants may appreciate a light feeding of a balanced fertilizer; and in alkaline or saline soil, a dose of iron sulfate. The shrubs may be propagated from seeds, new shoots from rhizomes or from stem cuttings.
The deciduous species, Berberis thunbergii (Japanese barberry) and its cultivars, are the most commonly planted. Low to medium-sized shrubs have densely massed branches covered with small, oval and sometimes variegated leaves that progress from green to yellow, orange, red or purple before they drop in fall. Tiny clusters of bell-shaped, yellowish green flowers appear along the stems in mid-spring followed by small red berries that punctuate the slender, arching, spine-covered branches in fall and winter.
B. thunbergii atropurpurea ‘Concorde’ is the runt of the genus, growing only 18 in. tall and wide. Its dusky purple-velvet leaves turn crimson in autumn when sited in full sun.
B. thunbergii ‘Crimson Pygmy’ (syn.‘Atropurpurea Nana’) changes from purplish red to brighter bronze red in the fall. If given full sun, its intense reddish color prevails all summer. At 3 x 3 ft. in maturity after several years, this easy-to-grow cultivar is among the most popular of the genus.
B. thunbergii atropurpurea ‘Golden Ring’ is named for a golden edge that rings its dark reddish-purple leaves in spring. This compact 3 by 3ft.cultivar bears the familiar bell-shaped, yellow flowers that are followed with red berries.
B. thunbergiiatropurpurea ‘Helmond Pillar’ may be planted as a row to accent its upright 4-6 ft. height and narrow 2 ft. width. As such, it can establish a backdrop to a perennial border or screen an unsightly view or it may even be planted singly to simulate a post. It typically has lovely bright reddish purple leaves and seedless fruits.
B. thunbergii‘Rose Glow’ grows 4-6 ft. tall and wide. New foliage is bronze red to light pink, changing to purple and bronze as it ages. Plant in full or lightly filtered sun for best color.
Berberis wilsoniae is an evergreen shrub to 6 ft. tall and wide, often with fountain-like arching branches that become covered with tiny yellow flowers in summer followed by deep burgundy berries that last into winter.
A number of other species are equally attractive and useful in the garden, but not as commonly planted. B. darwinii is a large evergreen shrub, with golden, almost orange flowers. B. calliantha is also evergreen, but quite petite. B. x stenophylla ‘Corallina Compacta’ is, as its name suggests, a low-growing, compact plant with coral berries.