One of the best ways to assure you will have a tree or shrub that you will be happy with for the long term, is to choose the right plant for the location. Know what size a tree or shrub will grow to at maturity. For example, it is extremely difficult to maintain a tree that wants to grow to 30 feet in a 14 foot tall space. By selecting a plant that will grow no larger than the area you have to work with, you can minimize the amount of pruning that will be required.

Select good quality bypass hand pruners and loppers. Bypass pruners are preferred because they make much cleaner cuts than the old anvil type that have only one cutting blade. Handheld pruners can be used to cut branches up to ½" in diameter while loppers work best on branches up to 1" in diameter. For larger branches up to 4" diameter, use a hand-held pruning saw. Be sure to maintain a sharp blade on all tools.

Viral diseases can be transmitted on pruning tools, therefore it is a good practice to sanitize your pruners before moving on to the next plant. A 25% bleach and water solution makes a good liquid cleaner. You may also use alcohol or a disinfectant such as Lysol^® spray to minimize the chances of spreading any disease.

The best time to prune is during the months of March and April. During these months the plant is still somewhat dormant, the branches are more visible, and the plant is likely to recover more quickly form any cuts that are made.

There are a few exceptions to this rule of thumb, however. Because of their susceptibility to oak wilt disease, oak trees should only be pruned during the months of December, January, and February.

Spring flowering shrubs like lilacs, forsythia, and magnolia should be pruned right after they have bloomed. Since flower buds on these plants are set in the prior summer, you will remove the buds if pruning is done too early in spring. Likewise, if pruning isn’t done right after flowering is complete, you may cut off next year’s buds which will be set already in the upcoming months.

Additionally maple and birch trees tend to "bleed" if pruned while their sap is running in early spring. It will not hurt the tree, however it looks awful. A better time to prune maples and birches is as their leaves are just starting to open.

Multi-stemmed Shrubs - Some shrubs like Weigela and Dogwood have many branches stemming from the base rather than one main trunk. For multi-stemmed shrubs like these it is best to "renewal prune" each year to control size and promote plant health. With renewal pruning, one-third of the branches are removed at the base of the plant each year, assuring the shrub is no more than three years old. To determine what third you will remove in a given year, first remove any damaged or diseased canes. The remainder of the third to be removed should then be the largest and oldest canes.

Spirea and Potentilla – While these are multi-stemmed shrubs, maintenance of Spirea and Potentilla are somewhat different because of the plants’ dense growth habit. To allow more sunlight into the plant and promote new growth from the base, first cut the shrub down to one-third of its size. Next, prune one-third of the canes at the base, again selecting the largest and the oldest branches.

Junipers and Yews – To maintain the natural look of these evergreen shrubs, avoid shearing. Instead, select the branches that are becoming too large and prune them back to a side branch. Make sure not to leave a stub. If your junipers or yews are very overgrown, keep in mind it may take several years to get them back into shape.

Spruce and Pine – It is extremely difficult, if not impossible, to hold back spruce and pine trees from reaching their mature size. One way to reduce their growth, however, is to pinch their "candles" when the plant is sending out new growth in June. With your thumb and forefinger, pinch off two-thirds of the new growth (the "candle") before it has a chance to expand. By doing this, you will promote side growth of the branches resulting in a much denser tree. If the tree is too large to manage through pruning, it may be best to remove the plant and replace it with one better suited to the location. Many dwarf conifers, for example, have been bred to grow more slowly and maintain a compact habit that virtually eliminates the need for pruning.

While most of the limbs you prune will likely be no more than an inch or two in diameter, you may need to cut larger branches. For branches of 3" or more in diameter, use the "triple cut" method to avoid tears that will damage the tree. First, make a cut approximately one foot from the trunk, sawing half way through the branch from the bottom. Make a second cut from the top of the branch about an inch or so farther out from the first cut until the branch falls. Finally, remove the stub at the base of the branch, taking care not to damage the collar.

Make sure all of your pruning cuts are clean, not ragged, in order to help the plant to heal more quickly. It is not recommended to use pruning paint to seal large wounds. The University of Wisconsin has conducted numerous tests, and the plant will actually heal more quickly on its own without sealer. Note, the one exception where pruning paint should be used is if a damaged limb must be pruned from an oak tree during the spring, summer, or fall months. Here, pruning paint will help seal out insects that may carry oak wilt disease.

If you are seeking more information, good pruning classes are available periodically through Green Bay Botanical Garden and the UW Extension office. There are also a number of good reference books available, such as Ortho’s All About Pruning.