Saturday | October 22, 2016
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Pruning in season for just the right reason

By Russell T. Nagata

University of Hawaii at Manoa

College of Tropical Agriculture and Human Resources

Komohana Research and Extension Center, Hilo

The one activity in the garden that gives many gardener’s trepidation and feelings of uncertainty is pruning.

In the natural world, trees and shrubs find their natural niche, compete for space and light and find a balance for survival. However, in our gardens we often try to maximize our square footage, number of species and varieties we grow, and the amount of fruit and flowers.

In short, we mold our plants into what we envision as the perfect garden. In its simplest form, pruning is to improve form and function of your plants in the garden and landscape. While most of us associate pruning with trees and shrubs, it can be practiced with vegetables, vines and annual ornamentals. While entire books have been written on pruning and I can’t cover everything about pruning, I will cover some of the highlights that I think are important.

Whether you know it or not, many of you have pruned plants. Removal of dead flowers to promote more flowers is a form of pruning referred to as deadheading. In many annual flowering plants, seed production is the natural outcome of flowering and when the hormonal influence of seed development is removed, the plant automatically reverts to the flowering mode.

The removal of the primary growing point to create a bushy plant and more flowering is also another form of pruning. The opposite is also true where all side buds and shoots are removed to stimulate a larger primary flower.

We all know pruning to maintain plant size as in large landscape trees and shrubs and the shape and form the tree. When pruning to improve tree form and function, branch angles that promotes strong branching is an important consideration. The creation of bonsai plants requires careful pruning and training of plants.

Sometimes we prune to stimulate the production of new growth, flowering and fruiting as old branches are removed to allow new ones to take their place. Removal of unwanted growth, diseased or pest infested branches, and broken limbs are other reasons to prune plants. Removal unwanted growth can also include reasons to protect property such as preventing branches and leaves from fall on buildings and vehicles, to improve line of sight and to allow more light to penetrate the canopy. Pruning can also be done to resize trees and shrubs that were allowed to out grow their space.

To do a good job at pruning you will need a few tools to complete the job. Hand shears are essential for general all around pruning in the garden. Pruning shears come in two general types, bypass and anvil. Bypass shears work like scissors and anvil type’s work like a knife on a cutting board.

Both types will cut branches ¼-to-½-inch in diameter with little difficulty depending on blade size and leverage the handles can create on the cutting blade. Lopping shears are great for cutting larger branches up to 1½ inches in diameter. For branches larger than 1.5-inch a pruning saw or chain saw will be indispensable. For neater cuts, finer saw blades, those with more teeth per inch is needed.

A pole pruner and saw can be a great addition that allows you to stand on the ground while working. It is very important when cutting large branches that you conduct a triple cut to prevent stripping the bark of your tree. To conduct a triple cut, the first cut is a third of the way through the branch on bottom side one foot from the final cut. The second cut is to the outside of the first bottom cut. The final cut is to remove the foot long stub. Since the majority of the weight is removed from the branch, the chance of tearing the bark is greatly reduced.

Whether you are standing on firm ground pruning a rose bush, on a ladder, or in a lift bucket, always remember safety first. Wear all safety equipment to keep you protected such as eye protection, gloves and shoes. Pruning while standing on the ground when possible is always a good first option. When pruning from a ladder, firmly position the ladder, do not over reach and it is better to move the ladder than falling over with it. Remember to keep fingers away from the cutting blade especially with one hand operated tools like the pruning shears. When pruning overhead be aware of falling branches and fruit, as well as electrical, cable and phone lines.

For more information on this and other gardening topics, please visit the CTAHR electronic publication website at or visit any of the local Cooperative Extension Service offices around the island. The Cooperative Extension Service office Master Gardener program is also a good resource for more information. There are also some very good YouTube demonstration videos online. I can be reached at


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