Grow red leaf barberry in full sun in well-drained soil. Lots of sunshine helps the foliage keep its color.
Fertilize red leaf barberry in spring just before it produces new growth. Apply 15-5-5 fertilizer to the soil around the base of the shrub and water to a depth of 6 inches. Follow the label-recommended application rate.
Water the newly planted red leaf barberry to keep the soil moist until it establishes. When it begins producing new growth, decrease irrigation frequency gradually until you are allowing the soil to dry out. This shrub doesn't require a lot of water, but during the summer, when the weather is hot, water weekly to a depth of 10 inches.
Prune the red leaf barberry right after it finishes flowering to keep it to the shape and size desired. Cut back overgrown shrubs to within 1 foot of the soil.