What You'll Learn

  1. Mistakes 1 - 2
  2. Mistakes 3 - 5
Leggy, woody, scraggly, spindly, yellowish, unkempt, and unsightly. No, it's not roll call for the cast of some dozing-princess fairy story. If you're like most people, it's the perfect description for that sad-looking hedge bordering your yard. Rows of thickly planted shrubs can be a handsome way to define borders and boundary lines, keep children and pets in (or out), and give birds shelter and even food. But like all shrubs, hedges need regular watering, feeding, and pruning to look their best. Though folks may forget to give roots a good drink in hot weather or to fertilize in early spring with a good 10-10-10 formula, the last area is where most of us really lose it. "A lot of people are intimidated by pruning, but it's a science anyone can master," says This Old House landscape contractor Roger Cook. "You just have to learn a few basics."

Here are some expert fixes for common mess-ups when it comes to hedge plantings.

Mistake #1: Shearing hedges without hand-pruning them

Using shears—whether hand-held pruners with long scissorlike blades or a power trimmer—to take off branch tips keeps hedges neat and tidy, and also stimulates bud production near the plants' edges. But as buds multiply, a shrub can get so thick that sunlight can't penetrate it, preventing interior growth. The result: a hedge that gets larger each year and looks lifeless inside. Proper pruning allows some sunlight to get in and enables you to cut back shrubs so they don't get too big.

So at each shearing, be sure to use bypass hand pruners to create some spaces in the hedge for light and air. Every few feet, reach inside and clip a branch or two at a 45-degree angle, just above a nub or leaflet that's growing in a direction you want to encourage.

If a hedge is old and seriously overgrown, you'll need to do some rejuvenation pruning using the three-year rule. Remove up to one-third of the thickest stems down at the base of the plant, stimulating new growth; repeat the next year, and the year after. This will leave you with a healthier shrub that's reduced in size.

Mistake #2: Pruning at the wrong time

Ideally, hedges should be pruned in late winter, when plants are dormant and haven't produced buds—particularly if you're cutting back drastically. "You don't want them to break bud before you prune because you want the plant's energy to go toward producing new growth where you want it," says Roger. "If you take off a plant's buds, you're cutting off spent energy, and it will take longer for the hedge to fill out."

Evergreens, in particular, require pruning early in the season; because they're generally slower-growing, they're likely to be bare (where interior cuts have been made), and off-color at the tips (too yellow) as new growth starts to show, well into the summer. Faster-growing deciduous hedge plants such as privet, spirea, and viburnum are more forgiving. With flowering shrubs, the golden rule of pruning is to wait until the day after blooms turn brown—that way the plant will have time to set buds for next year, whether it blooms on the current season's wood or the next's.
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