Garden Topics:
Pruning Made Easy

Late winter is an ideal time to prune. Plants are often still dormant, so they haven't expended energy pushing out foliage that is about to be lopped off. And without foliage, it’s easier to see a deciduous plant's structure, so defects are more apparent. Before pruning, look at the specimen from all angles and envision where cuts will be made. This can save you from making mistakes. Remember that annual, moderate pruning to maintain a good framework of well-spaced branches works better than severe pruning to rescue plants after years of neglect.

Training

Aside from small species and those intentionally grown with multiple stems, trees are best grown with a single leader. Some species continually develop forked trunks that need to be pruned back to one leader. Others, such as this larch, may develop competing stems only after the death and removal of the original leader. Choose the straighter and more vigorous of the stems, and then cut back the other halfway. Tie the chosen leader to the cut stem so it will grow up straight. After a year, cut the tie and remove the shorter stem.

Removing

Some species send up new stems from the roots (suckers) and from the trunk, or branches (water sprouts). This ungainly, upright growth mars the shape of the plant and can cause problems later. The new flushes of growth begin to crowd as they mature, rubbing against each other and against existing stems to create entry points for insects and disease. Look for these whip-like growths in early spring and remove with loppers. Those originating from the trunk can be pulled by hand to discourage further growth.

Trimming

In the forest, trees prune themselves, shedding lower branches as they compete for sunlight. In an open landscape, lower branches remain and may need to be removed to create headroom for pedestrians or lawn mowers. When removing branches, avoid leaving a stub (see photo, far right), and keep at least 60-70 percent of a deciduous tree's height in canopy. Anything less and the tree looks like a lollipop.

Reinvigorating

Some shrubs, such as butterfly bush (Buddleia), are marginally hardy in cold climates. Roots survive harsh winters, but stems die back to the ground. Remove the dead stems with loppers, cutting as close to the ground as possible. Reinvigorate other shrubs, such as yew, spirea, viburnum, and mock orange (Philadelphia), in a similar fashion, with one exception: Because the stems on those species should be alive, leave 4-5 inches of stem from which new growth can sprout.

Shearing

There are two ways to shear a hedge: formally or informally. Electric or gas--powered hedge trimmers are often used for the razor-straight edges of a formal hedge because they make the task easier and quicker. Manual shears are more suited to informal shearing. Here, we tidy up a yew (Taxus) by removing overly long shoots using manual shears. Even after the trimming, the shrub maintains a somewhat informal look.

Thinning

While most gardeners are thrilled to see a lot of growth on their newly planted trees and shrubs, the plant's long-term health will benefit from structural pruning when young. Thinning is the removal of internal branches that cause crowding. Look for branches that cross, rub against each other, or grow inward instead of outward. The goal is a structurally sound tree or shrub with well-spaced branches. Smaller trees, such as this Amur maple (Acer ginnala), will mature at under 25 feet, so it is not critical to have a single, straight trunk. In fact, the plant will be more interesting with twisted stems.