Pruning practices for trees and shrubs are basically identical, especially if you are dealing with a tree or trees you wish to maintain as a shrub or hedge by pruning. Most trees and shrubs, evergreen or deciduous plants, require occasional pruning to control height, width, to thin branching or to remove dead, diseased or rogue branches that may blemish overall appearance. Pruning is also used as a means to stimulate flowering and fruiting and promote vigorous growth. Large overhanging branches may need to be removed if they pose a potential danger to buildings or people. Mature trees seldom require pruning.
A home gardener may be dealing with an already-established garden, or one that is being initially landscaped or renewed. In an established garden, pruning maintenance will be dictated by the trees or shrubs already present and their respective growth habits. Unless the homeowner wishes to replace certain plants, a regular pruning regime can be set and followed. If initial landscaping is taking place, or renewed, the homeowner has the opportunity to choose new species of trees and shrubs to be planted and select trees or shrubs which require greater or lesser amounts of pruning.
Hedge, espalier and topiary growth require the most pruning work. To maintain a uniform surface on the top and sides of hedges, they need regular pruning, the frequency varying with the plant and season. Specific shaping of shrubs or trees to form espalier growth against a flat surface, such as a wall or fence, requires shaping the branches and supporting them with wires and nails. Creating topiary plants from trees or shrubs demands a lot of pruning to mold the plant into the desired shape, often fancifully resembling animals. For intricate figures, a wire cage may be constructed and placed over the tree so the branches can be trained on the cage which serves as a pattern of growth. Once the basic desired effect of either espalier and topiary is achieved, maintenance pruning of shoots and leaves is required as needed. The ultimate art of pruning is represented by bonsai plants, which are regular trees kept to a height of a foot or less. Bonsai are grown in pots by careful shoot cutting and training, defoliation, root pruning, watering and specialized plant foods. Wires and clamps are often used to achieve the desired effect. This Japanese art form has produced plants that will live for hundreds of years and are passed down as family treasures from one generation to another.
The timing of pruning should be based upon the flowering, fruiting and growth habit of the plant. Most trees or shrubs can be pruned at any time of the year, although it is better to prune certain trees on a regular annual cycle. Pruning should be done by hand using shears or a saw. Wound dressing is now deemed unnecessary. Trees prone to bleeding should be pruned in mid-summer or late fall. The general rule of pruning is to allow a tree or shrub to develop its natural shape. Hedge maintenance generally requires multiple prunings in a year, using mechanical, electric or gasoline powered clippers.
The key to successful pruning is to know the tree or shrub you are working with, taking into account its special requirements as applicable. The more than 200 tree and shrub descriptions on the TreeWorld website provide basic information about growth and shape to aid in successful pruning.