Maintenance IV: Pruning
Pruning is the cutting off of parts or branches of a shrub or tree to improve shape or growth. Gardeners often tend to over-prune in traditional gardens. However, in a water-conserving garden, you don’t have to prune too often. The key is to know which plants need pruning, and when and how to prune. When plants are located in areas with adequate space, the need for regular pruning usually is greatly reduced. However, some minor pruning may be necessary at times and can be beneficial to plants if done properly.
In most plants, the need for pruning arises at some stage of their life, and the reasons for doing this vary from plant to plant. Mature plants may require annual pruning for a number of reasons. Most important is preventing the plant from becoming overgrown. When overgrown, plants develop a tangled mass of stems, with many of them rubbing against each other. Also, pruning is an opportunity to remove dead and dying stems and branches. This helps in preventing disease and decay from spreading to other parts of the plants, while keeping the plant in a neat and healthy state. In addition, pruning rejuvenates plants, thus encouraging the plant to produce young and healthy foliage, flowers, and fruit. A number of ornamental shrubs flower mainly or exclusively on young growth, with the size and number of flowers diminishing when carried on older, overgrown branches. For a shrub that is mainly grown for its foliage, regular pruning will help it produce bigger and more intensely colored foliage. Also, the color of young wood is sometimes an attractive feature of some shrubs, and may be lost as the wood becomes older. The issue of aging wood also applies to fruit-bearing trees and bushes, which produce fewer and smaller crops on older wood. In addition, pruning helps create special shapes as in topiary, where the regular pruning and training of a tree or shrub is done to achieve and maintain a desired shape. Finally, some plants have a vigorous habit of growth, and require pruning to restrict their size, which can be an important issue in a small garden.
Generally, plants should not be pruned immediately after planting except to remove dead, diseased, or protruding branches. Other than that, light pruning may be carried out anytime if proper pruning techniques are followed. For deciduous plants, heavier pruning should be carried out when plants are dormant (after leaf drop in the fall or before bud break – the projection on stem of undeveloped shoot, leaf, and/or flower - in early spring). In general, avoid pruning when plants appear stressed or during periods of prolonged heat. Keep in mind that pruning stimulates growth, which requires additional water. Therefore, reduce pruning during dry periods.
Once your landscape is established, you will have to carry out maintenance pruning. Of course, if you select the proper plant for its location and provide it with adequate space, this will greatly reduce the need for pruning, or even eliminate it in some cases.
This article is part of a series of articles prepared by the Center for the Study of the Built Environment (CSBE) on water conserving landscapes.
For additional information on water conserving gardens, visit the CSBE web site at www.csbe.org
Support for the CSBE project on water conserving landscapes is provided by WEPIA (Water Efficiency and Public Information for Action), a program being implemented in collaboration with the Ministry of Water and Irrigation and funded by the United States Agency for International Development (USAID).