Barberries (Berberis spp.) are a large family of shrubs, all of which are valued for their low-care needs, according to the University of California. These easy-to-grow plants vary in size depending on the species and cultivar. They often have colorful foliage, as well as winter berries and long thorns. There are three barberry shrubs commonly grown in the United States. They are the Japanese barberry (B. thunbergii), wintergreen (Berberis julianae) and mentor (B. x mentorensis) barberries.
In general, barberry shrubs grow best in temperate climates, with mild summers and cool winters. The Japanese barberry, which is the most commonly grown in the United States, according to the University of Illinois, grows best in U.S. Department of Agriculture (USDA) plant hardiness zones 4 through 8. The mentor barberry is not as cold-hardy as the Japanese species, growing only to USDA zone 5. Wintergreen barberries are only cold-hardy to USDA zone 6 but are tolerant of hot, dry conditions.
Barberries vary in their size and growth rate according to species. The Japanese barberry has moderate growth, at around 1 to 2 feet per year, according to Clemson University. This species will reach a maximum height and width of 6 feet. Wintergreen barberries grow slowly, at a rate of about 15 inches per year, and can get up to 8 feet tall and 6 feet wide. Mentor barberries are the fastest growing. These shrubs grow at least 2 feet per year and have a maximum height and width of 7 feet.
Barberry shrubs are very hardy, adaptable plants. They can adjust to all types of soil, even in urban, polluted areas. They are drought-tolerant and grow equally well in full sun or partial shade. In addition, these plants are easy to transplant. Barberries can be pruned after flowering but look best when left alone, according to Clemson University. Avoid planting these bushes in very wet areas that may collect standing water or are prone to flooding. The shallow roots of the barberry may suffer from root rot if kept consistently wet.
Barberries are hardy shrubs and do not usually suffer from serious diseases, according to Clemson University. Still, they can develop unsightly fungal diseases, such as leaf spot, if water is left to sit on their leaves. Avoid this by watering at ground level. Aphids, scale and the barberry webworm can also infest the plant. While they do not pose a threat to the life of the shrub, they can be an unattractive sight and can be rinsed off with a strong stream of water or killed with insecticide.
Barberry shrubs grow well when grouped together, especially for use as barriers or hedges. These plants are quite thorny, which can be an advantage when trying to keep deer out of other, tastier parts of your garden. They can also be used as a specimen plant due to their colorful foliage, which can persist even into winter, and berries, which also cling a long time to the branches.