Except with formal hedges that need shearing one or more times a year, pruning should be kept to a minimum. Shrubs that become overgrown may be revitalized by cutting them back very severely, even to within a foot or so of the ground, in late winter. Fertilize the shrubs in spring. Normally, barberries are not seriously affected by diseases and insects. Scale insects, which can be controlled by applying dormant horticultural oil in the spring before growth begins, or with labeled pesticides when the crawlers are active.
Crawlers are the immature forms that hatch from the eggs.
They are not protected by a scale like the adults. The barberry webworm, which is a small black caterpillar with white spots that ties together the leaves and shoot tips. There are many cultivars available. The leaves assume reddish to purplish shades. The yellow flowers are tinged with purple, but the fruits are the same bright red as those of the species.