Late winter early spring is a good time to prune trees and shrubs. The major reasons for pruning are to improve plant structure and safety, or to control size. Other objectives can be to repair storm damage and to provide clearance from objects and traffic. Remember, good pruning includes eliminating objectionable growth. This means ridding plants of dead, dying or diseased branches, crossing or rubbing branches, waterspouts from limbs, and co-dominant or forking stems.

Deciduous Trees
The latest research shows that the best time to prune shade trees is between late February and early May. Trees pruned at this time in early spring develop a callus (i.e. wound-wood) around the cut much more rapidly than those pruned at other times. Proper technique is essential for best results. Execute "natural target pruning" making cuts on live-wood outside the branch bark ridge and the branch collar. (Fig.1) When removing dead stems, the severing cut should be at the point where the dead and live-wood meets. (Fig. 2)

Some trees are known to "bleed" (i.e. sap oozing) excessively following pruning in early spring. Maples, walnuts, birches, beeches, hornbeam and yellow-wood are good examples of sap "bleeders." Don't worry, the "bleeding" may be unsightly, but it is not harmful. It can be prevented by pruning these species after the foliage has emerged. One final caveat: Spring flowering trees (i.e. Dogwood, crabapple, magnolia, cherry, etc.,) should be pruned after flowers have dropped. To do otherwise, will remove the flower buds and, hence, the chance for flowers.

Coniferous Trees
To satisfy general concerns mentioned earlier, conifers should also be pruned in the late winter-early spring period. To create a denser plant, however, wait until the new "candles" form (i.e. elongated terminal and lateral shoots) before pruning. Then, cut the "candles" in half before the needles unfurl. Repeat this process each year for a smaller, more compact plant. (Fig.3)

Deciduous and Coniferous Shrubs
Lackluster shrubbery performance is often due to neglect. As a result plants often become leggy, rank and full of dead or declining stems. The key to maintaining healthy, attractive growth is to keep the wood young and vigorous. Pruning plants on a regular basis is what's needed. Use the following four basic pruning operations for maintaining productive, high quality shrubs. They are; heading back, renewal, rejuvenation, and shearing.

Heading back is used to control the size of the shrub. It requires that a branch be removed to a bud or lateral branch. Heading back is best done when new growth is complete. Plants that respond favorably to this treatment are rhododendron, mountain laurel, azalea, winged euonymus and other plants with stout, single or double trunks. (Fig.4)

Renewal is the removal of old over grown stems or canes. It involves the elimination of 1/3 of the total stems each year. The goal is to produce a plant with entirely new top-growth every 3 to 4 years. (Fig. 5) This treatment is best done in winter when plants are dormant. This is an excellent way to re-invigorate multi-stemmed plants such as spirea, forsythia, hydrangea, buddleia, and weigiela.

Rejuvenation is a harsher form of the renewal method. Instead of cutting a portion of stems each year, it involves cutting all the canes at ground level in a single season (Fig.6) Rejuvenation is the pruning technique of last resort for very old, mis-shapen, or poorly structured shrubs. It is tantamount to topping and promotes new shoots to sprout from latent buds that can be trained into nice plants in future years. This pruning method is a very effective way to restore poorly growing forsythia, hydrangea, privet, honeysuckle, lilac, boxwood and spirea. Pruning should be done in late winter or early spring.

Shearing is used to shape hedges into geometric forms.
Proper shearing technique results in a hedge with a narrower top than bottom. (Fig.7) This plant shape allows sunlight to reach the lower branches, keeping them alive. The best time to shear is when new growth is complete.

Pruning principles and methods are taught at the Tree Stewards Education Course held in spring and fall each year.