Another important thing to remember is never to leave a “stump”. Always prune to a side branch or growth bud because if you leave a stump, you are inviting disease. When pruning to a side branch, choose one that is going in the direction you would like your plant to grow and is at least 1/3 the size of the original branch. A wimpy side branch might not have the necessary strength to take on a leadership role.

A third very important pruning rule is DO NOT SHEAR any plants in your garden except for hedges. Not only is it desirable to maintain the beauty and individual shape and form of each plant, shearing creates a lot of re-growth at the point of the shearing cuts. This is great for hedges where you want thick, dense growth for plants used as architecture, but not for plants being grown for their foliage and/or flowers. Prune hedges slightly wider at the base than at the top to avoid shading out the bottom.

The alternative to shearing is thinning or drop-crotch pruning. With this type of pruning, a specific choice is made as to where the pruning cut is to be made and why. These decisions are based on the information given above. I suggest reading official pruning manuals. (See recommended book list)

The art of pruning is not difficult, and it is one of the most satisfying activities in the garden. Like other art forms, half of art is knowing when to STOP! A good rule of thumb is never to remove more than 1/3 of a plant at a time.

I strongly recommend that your trees be assessed and/or pruned by a licensed arborist every one to three years.

Pruning Azaleas
From Sunset's Azaleas, Rhododendrons, Camellias

Unlike most Rhododendrons, Azaleas have growth buds all along their stems, just under the bark surface. As a result, new growth will originate close to any cut you make.

Most evergreen azaleas need little pruning other than removal of weak or dead wood and whatever trimming is required to keep plants shapely or within bounds. If you want a compact plant rather than one that is open and irregular or picturesque form, just remove stems that interfere with the desired effect, cutting them back to their points of origin on other branches.

The best time of year to undertake any pruning or trimming is right after plants finish blooming. New growth formed after such pruning will likely bear flower buds for the next year's bloom. Pruning after midsummer will cut down on the number of blossoms the following year since flower buds begin to form at that time.