One exception to the spring pruning rule is birch trees, which should only be trimmed in July. Another exception is spring flowering shrubs. Prune them right after they bloom, so they can develop new buds for next year's flowers. If you prune them after they set buds, you may not get any flowers the next season.

There are two ways to prune shrubs, thinning and heading. When you thin a shrub, you remove the entire branches all the way down to where they began. The shrubs will usually put out twice as many new branches from the bottom. It results in a more open, natural looking shrub and does not change its basic shape.

The second alternative is called heading.  Heading is shortening the branches to achieve a denser more sculptured look to the shrub. If you want to contain the shrub, cut the branch down to a bud facing the inside. Heading is a lot more labor intensive, because pruned branches send out new shoots all summer long. It does add a more formal "clipped" look to your landscape, if that is your preference and you don't mind the upkeep.

All the advice the tree specialists gave us in the past about pruning trees has gone by the wayside. They often advised sawing the branches off flush with the tree trunk and then coating the wound with tree paint. Don't do either one. The first thing to look for before you prune is the tree collar. This is a doughnut of living callus tissue, where the branch meets the tree trunk. It serves as the tree's natural defense against pests and diseases. After you find this darkened line of rough bark, cut on the outside of it at a 45 to 60 degree angle. This will insure that the tree will scar over the wound and be as good as new. Don't use tree paint. If you made the cuts properly, you don't need it and if you didn't -- it won't help.

Use a drop cut for larger tree branches. Make your first cut an undercut about halfway through the bottom of the branch, a few feet from where your final cut will be. The second cut is made into the top of the limb just outside the first. Cut until the branch snaps off. This will get rid of extra weight so that the branch doesn't tear into the collar and trunk as it comes off. The third cut will be your final one on the outside of the branch collar.

When trees are young, you can remove a great amount of wood with no ill effect. As they mature you should remove less and less. Never remove more then 1/3 of a tree or shrub at any time, and never cut the entire top off of a tree (or let a tree service, either). Topping causes a flush of new growth which severely weakens the tree. This makes it all the more susceptible to damage from pests and disease. Use crown reduction pruning and thinning instead, and do not remove more then 1/3 of the canopy.

Make sure all your pruning tools are clean and sharp before you start. Remember, you don't have to finish all the pruning in one session...or even one season. I have a real problem curbing my tendency to cut everything in sight once I get started with those pruning shears. I think I'll cut a few of the worst ones today and then come back to it when my shears (and enthusiasm) have cooled down a bit.