1128 Berberis thunbergiiCommon Names: Japanese barberry Family: Berberidaceae (barberry Family)
Japanese barberry is a compact, rounded little shrub with dense foliage consisting of tightly packed deciduous leaves that are borne in clusters along the stems, which are themselves armed with one-half inch (1.8 cm) spines. There is a spine at the base of each leaf cluster, but they are rather puny and particularly vicious. The leaves are about an inch (2.5 cm) in length, bright green above and glaucus-bluish beneath, and they turn shades of red, purple and orange in autumn. Japanese barberry produces subtle clusters of restrained pale yellow flowers that give way to showy bright red berries. The bush rarely exceeds 3 ft (1 m) in height, but often grows wider than that. There are literally dozens of cultivars in the trade, including dwarfs that rarely get a foot (30 cm) tall; some erect selections that get 5 ft (1.5 m) tall; forms with yellowish juvenile foliage; many with purplish foliage; some with variegated leaves; some with white-speckled leaves; and many selected for their brilliant autumn color or showy red fruits. 'Crimson Pygmy', growing to around 2 ft (60 cm) tall and 3 ft (1 m) wide, with purplish red autumn foliage, is perhaps the most common cultivar.
Berberis thunbergii is a native species in Japan where it grows in thin woods and on rocky hillsides. Japanese barberry has become established in parts of northeastern North America and has been classified as an invasive species in some areas.
CultureLight: Japanese barberry does best in full sun to partial shade. Plants grown in full sun usually produce more fruit and have better fall color. Moisture: Japanese barberry likes a well drained soil and regular watering. It is quite tolerant of drought, and does well in dry, rocky soils. Barberry suffers in soils that are constantly moist. Hardiness: USDA Zones 4 - 8. Japanese barberry can be grown in zone 9 (provide partial shade), where it is almost evergreen. Propagation: Young, fast growing softwood cuttings are easy to root. Stems often root where they touch the ground. Plants grown from seed will likely not look like the parent, and the large number of selected cultivars is testament to the extreme variation among seed-grown plants.
Japanese barberry makes an excellent hedge; it grows naturally in a much-branched, dense, compact shape, and withstands hard pruning. Select the taller cultivars for hedges. The attractive autumn foliage and the pretty red berries that often persist well into winter are other reasons to consider this popular landscape shrub, especially positioned in masses. Many of the smaller cultivars are excellent in rock gardens. The fruits are eaten by birds.
There are over 400 species in the genus Berberis, occurring throughout the Northern Hemisphere, as well as tropical Africa and South America.
All parts of the barberries are said to be mildly toxic if ingested. Berberis thunbergii is an alternate host for the wheat rust fungus and its cultivation in Canada is prohibited. Although the species is known to be invasive in the northeastern U.S., and should not be cultivated in that region, it has not yet become a problem in more southern regions. Nevertheless, gardeners should consider shrubs with similar properties that are native to North America as alternatives to Japanese barberry. These include wax myrtle (Myrica cerifera), yaupon holly (Ilex vomitoria), and Walter's viburnum (Viburnum obovatum), among others.
Steve Christman 1/17/11; updated 6/7/11