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Many types of evergreen shrubs and trees need little or no pruning to keep them in prime condition.  Some of the more vigorously growing evergreens, however, such as the Pfitzer juniper, may require moderate, periodic pruning.

If frequent pruning is necessary to keep faster growing plants in bounds and to prevent them from interfering with a walk, driveway or view from a picture window, the homeowner should consider replacing such plants with a slower growing type or one of a different growing habit.

Pruning Guidelines

Broad leaf types, such as the Oregon hollygrape, should be pruned little, if at all.  If pruning is necessary, it should be done lightly just after bloom (late spring).  Occasional corrective pruning of such plants to remove unwanted shoots may be done almost anytime, providing the cut is made just above a side branch.

Trees or shrubs of narrow leaf needle type, such as pine, spruce and fir, are pruned according to growth characteristics.

Those that produce side buds on the shoots, such as spruce, fir and Douglas fir, should be pruned by cutting the tips back to the desired length in late winter or early spring when buds are dormant.  The recommended place for cuts is just above a side bud or side branch.

In plants which produce few side buds, such as pines, pruning may be accomplished by pinching or snapping off with the fingers a portion of the young growth "candles" that form in late spring and early summer.  The proper time to prune is when the "candles" snap off easily and cleanly.

Cutting these plants with a knife or shears should be avoided, since this method invariably injures some of the needles and later gives a plant a general brown appearance.

Plants with scale-like leaves and no definite buds, such as junipers and arbor vitae, may be pruned at anytime except during sub-zero weather.

The optimum time for using hedge shears to prune an upright evergreen is just prior to the new growth in spring and again in late June or early July.  Cutting marks thus will be covered up by the flush of growth.

The use of hedge shears is not recommended on spreading evergreens like the Pfitzer juniper.  To obtain a natural look on this type of plant, the homeowner should prune to an upward growing branch or bud.  Careful pruning will allow the remaining lateral branch to hide the pruning cut.

Pruning Practices to Avoid

Top leader pruning in evergreens, such as spruce or fir, should be avoided.  Cutting into the woody portion of such growth often will result in a multiple top and ultimately destroy the natural shape.  Multiple-topped evergreens also are more prone to storm damage from the weight of heavy snows.

Frequent light shearing of upright evergreens like junipers is not recommended except to obtain a formal effect.  Frequent shearing encourages dense growth on the perimeters of the plant.  This growth shades out the growth on the inside.  When a branch on such a plant is damaged by a storm, a large and obvious gap results.  Repair of such damage is often slow and difficult.

Vigorously growing evergreens like the Pfitzer juniper should not be planted close to the foundations of a house, in front of a low picture window or anywhere where frequent pruning is necessary for control.  Pruning to correct size in this instance is only a temporary and unsatisfactory method of control.

Courtesy of the Colorado State University Cooperative Extension (10/88)

    by James A. Feucht