Overgrown hedges make a home look neglected, yet many gardeners fail to prune hedges carefully because they're intimidated or unsure of what to do. Gardeners with bushy overgrown hedges and shrubs have two choices: perform a drastic pruning or follow a three-year rejuvenation program to shape up their hedge. Once the hedge or bush has been properly pruned, regular trimming prevents future dishevelment.
Cut a large overgrown bush or hedge back in March or April, leaving only 4 to 6 inches above the ground. This drastic pruning method works well on hedges and flowering bushes like forsythia, dogwood and lilac. Cautious gardeners can try the long method.
Remove up to one-third of the large old-growth stems from your shrub or hedge by cutting them off at the base. Choose stems that are thick and woody. This will spur the plant to produce lots of new growth over the growing season. Leave the hedge alone until the following year.
Prune out another third of the old growth wood during the second year. Thin out the new growth and leave vigorous shoots at well-spaced intervals along the length of your bush. Wait until the following year to complete the pruning.
Prune out the remainder of the old wood. Thin new growth again, removing shoots from crowded areas.
Shear your bush or hedge with hedge clippers to maintain it at a desired height. Hedges can be sheared three to four times in a season, according to the University of Missouri. Shearing can keep your hedge at a good height, but should be used in combination with rejuvenation pruning to maintain a compact, healthy hedge or bush.