Gardening in Hawaii is unique do to the tropical islands and Hawaii's regional hardiness zones of 10A to 11. This means most trees benefit from nearly a full year of growth, and gardeners are able to prune almost anytime throughout that time frame. Pruning helps gardeners maximize the health and overall vitality of the plant and is highly encouraged by the University of Hawaii.
How to Prune
Gardeners prune their trees by using bypass shears or a pruning saw to cut off overgrown areas of the tree. Avoid tearing the branches of the tree, and make clean cuts at a downward 45-degree angle. Remove the branches that are too close together or that make the tree appear uneven.
Parts of the Tree
Gardeners should focus on removing dead portions of the tree to cut off and reduce infections. Dead limbs that are unable to grow integral plant organs such as leaves or branches need to be removed to limit the amount of resources a tree wastes.
The most important areas to prune are any areas that have obvious symptoms of fungal infection, such as tree cankers, spotted leaves, leave curl, or sooty mold. Removing these is a primary step in restoring the health of any plant. Since Hawaii has favorable growing temperatures for many fungal diseases, the infections can spread rapidly throughout the entire year.
When to Trim
Gardeners in Hawaii usually only need to prune their trees once or twice a year to control a plant that becomes unruly. Any more than this and you should consider replanting the tree to a new location. Do this directly after Hawaii's short winter season, when plants end their growing period. For trees that bloom year-round, gardeners need to prune after each blossoming.
When pruning areas of the plant that have been infected, gardeners in Hawaii have to dip their tools into mixtures of 70 percent denatured alcohol and 30 percent water to avoid spreading infections between plants areas and individuals after each cut. All diseased plant parts need to be removed from the area to help keep the fungal spores from spreading to uninfected plants.
Never trim a tree with non-garden tools such as knives or machetes. These can increase the risk of infection by cutting the plant improperly. Certain garden tools such as hedge shears should not be used for anything other then creating aesthetics in hedges as they generally leave plants with jagged branches that can easily absorb fungus and disease.