Red barberry is a hardy, heat-loving ornamental shrub that is grown widely in the desert southwest. Also called "Desert Holly," red barberry is hardy enough to withstand extended dry periods and extreme heat. Red barberry will tolerate temperatures below zero, but it won't survive extreme winters in the far northern states. An evergreen shrub, red barberry will present yellow blooms during the spring. Attractive, bright red berries appear in autumn and brighten up the landscape all winter long.
Plant the red barberry bush in partial sunlight if your climate is extremely hot during the summer. Otherwise, red barberry will thrive in full sunlight. Avoid planting red barberry in poorly-draining soil or soil where rainwater tends to pool for more than half a day. Although the red barberry can grow in poor, rocky soil, it won't do well with wet feet.
Keep the soil moist for the first few weeks after planting red barberry. Once the red barberry bush is established, which is indicated by new growth, it will only need to be watered during hot, dry weather. Red barberry can tolerate extended dry periods, but it won't tolerate excessive moisture, so be careful not to overwater.
Apply 2 to 3 inches of organic mulch around the base of the red barberry bush. A mulch such as pine needles or shredded bark will discourage growth of weeds, enrich the soil, and protect the red barberry from temperature extremes.
Fertilize the red barberry bush as soon as new growth appears in the spring, then reapply fertilizer at four- to six-week intervals until early autumn. Use a granular fertilizer formulated for trees and shrubs at the rate indicated on the package. Broadcast the fertilizer around the base of the red barberry bush, over the top of the mulch, but avoid getting fertilizer on the foliage. Water the fertilizer in thoroughly.
Prune the red barberry bush before growth emerges in early spring. Prune branches that were damaged by wind and weather during the winter, as well as branches that look weak and spindly, or are growing across other branches. Trim any branches that detract from the desired shape of the bush. Pruning is important the first two years because it will encourage the plant to grow full and bushy. After the first two years, prune lightly in early spring as needed.