There are between 400 and 500 species of Barberry bushes (Barberis), but only a few are grown in the residential landscape. The most popular is the Japanese barberry (Clemson) which grows from 3 to 6 feet in height with a 4 to 7 foot spread, and is used as a hedge plant. Pruning the barberry should be kept to a minimum, according to experts at Clemson University, and should be performed right after flowering. Barberry stems are quite thorny, so you will need heavy gardening gloves and to use caution when pruning.
Remove any growth that is thinner than your finger. These stems are generally located toward the bottom of the shrub, sometimes even sprouting from the soil.
Prune off all dead branches to their point of origin. Cut any branches that are crossing over other branches. These can rub against the other branch, creating an opening for pests and fungus.
Cut off shoots that protrude from the overall shape of the shrub. Cut these back so that they are aligned with the outermost branches of the barberry.
Remove insect-infested and diseased branches last. Cut these back to the ground or their point of origin and immediately bag them.
Clean up the planting area by raking up mulch, small twigs and other pruning debris.
Water the barberry shrub until the soil is saturated. Allow it to drain.
Apply a 3-inch layer of mulch, completely encircling the barberry shrub, 2 inches away from the base. Spread the mulch to the edge of the widest part of the barberry.