June is the beginning of hurricane season in Hawaii. Most years we are fortunate to have them pass us by. Generally, tropical disturbances start off the coast of Mexico and move westward. Occasionally, they develop to the south or west of us and aim this way. We have enough warning to prepare for these storms, but don’t wait until the last minute. Now is the time to consider some general pruning needs in your garden. By proper pruning, you can avoid much of the damage caused by strong storm winds.
Since some light is essential to plant vigor, it is a good idea to open up those heavy canopied trees. But don’t overdo it or exposed plants will get sunburned.
Even if we never had storms and you were careful to select the right trees for your yard, and shade lovers for underneath, there comes a time when you have to consider pruning.
Whatever the natural form of the tree is in the beginning, it should be maintained, and this means individual handling of each problem. Trees should not be butchered or “hat racked.” This creates a dense mass of branches that may make a tree even more susceptible to wind damage.
Some knowledge of pruning is necessary for the gardener who does his own work. A good set of pruning tools, including a pair of side-cutters for removing twigs and small branches, is necessary. You will need a pair of loppers for cutting branches up to three-fourths of an inch in diameter, a pruning saw, a tree pruner on a pole, and if you prefer, waterproof paint for covering pruning wounds. Some schools of thought believe that pruning paint is of no value; under some conditions, this is the case. Other folks swear it keeps the bugs and rot out if you are careful to reapply the paint when it begins to deteriorate.
Pruning should be done for a purpose, such as to maintain shape, remove diseased or awkward branches, or to reduce the size of a vigorous grower. An example of overpruning is the damage that was done to the great old Australian banyan at the popular surf spot on Alii Drive. The tree died some years ago after a severe butcher job. Some folks say it was caused by someone poisoning the tree because it blocked the view. Keiki from the century-old tree were replanted. Recently, a new tree was heavily pruned, causing concern it, too, was under attack. Time will tell, but trees like these are living entities and should be respected and protected, not destroyed.
Pruning is important for several reasons. Trees that respond to day length and bloom during the winter or spring months should be pruned through the summer months. Their final pruning should be before September. Fruit trees should be pruned after the main fruiting season. This will vary with variety.
Trees likely to be damaged during periods of high winds should be pruned to decrease damage caused by the storms.
Trees should be pruned in such a manner as to remove approximately one-third of the existing branches deep into the canopy. It should not be too noticeable. Of course, weak and diseased branches and twigs should be removed at any time noted. Citrus trees may be gone over lightly two or three times a year. Such pruning is done from the inside. Dead wood and “water shoots” or suckers should be removed as they appear. When a weak or unwanted branch is removed from a healthy branch, it is cut off even with the branch itself. Do not leave a stub. This discourages disease and insect damage.
Palm trees require a different approach. Many palms, especially those with crown shafts, are self-pruning. It is best to wait until older leaves yellow and are almost ready to drop. Cutting them too early may weaken the tree. This causes a condition referred to as pencil top. The trunk gets so thin that it will snap off during a strong wind. Using spikes to climb palms can spread disease and is not good for the trees. Pruning equipment should be sterilized when going from one tree to another. If not, it can spread diseases like bud rot. It is a difficult call when we have to balance the health of the palm versus the cost of frequent pruning and safety. Choose palm species that do not require constant leaf and fruit removal. When it comes to coconut palms, consider planting the Samoan dwarf, Syagrus amara or Beccariophoenix madagascarensis.
Large tree work can be dangerous. Unless you are experienced and have good insurance, don’t tackle the job yourself. Hire a certified arborist. They know what they are doing. Be sure whomever you hire has the proper insurance or you could have a lawsuit on your hands that could do more damage to your pocketbook than a hurricane!
This information is supplied by the University of Hawaii College of Tropical Agriculture and Human Resources.