Barberry (Berberis) grows wild in many neighborhoods, and when left to its own devices it can become invasive. In some places, the plant is illegal to grow because it carries a rust disease that infects wheat crops. Choose a "well-behaved" form like Japanese barberry, which has lovely red leaves and is hardy to Zone 4. Shear barberry shrubs into a bushy hedge or allow them to grow into their natural arching form. Barberries are drought tolerant and grow even in poor soils.
Shear the barberry bush back to 6 inches above the ground immediately after planting and again the following spring. This severe pruning during the first two years of growth will ensure that the barberry becomes bushy on the bottom. Otherwise, the bush will put energy into height and will have patchy bare spots on lower branches.
Shear your barberry bush annually in the spring for a hedge. Shear off the tips of all branches to create a smooth, uniform look. Maintain hedges by shearing two or three times during the summer. Stop shearing in late summer, four weeks before the first expected frost, to allow the shrub time to harden off and slow down growth before winter.
Prune lightly in spring for a more natural form. Cut out any dead wood or branches that rub against each other or grow vertically. Cut out diseased wood, dipping your pruners between cuts in a disinfecting solution of one part chlorine bleach to nine parts water.