With hurricane season upon us, you should know how to minimize wind damage to your landscape. Trees and shrubs can grow too large or unbalanced to be able to withstand windstorms, so it is wise to learn how to prune and shape trees in order to minimize damage.
Avoiding storm damage begins with the initial selection of your plants. You should take into consideration the branch and trunk strength of the trees being planted, how strong their root systems are and their placement near structures and utilities. Trees planted in wet areas, like swales, or close to sidewalks and driveways can develop stunted root systems, allowing them to blow over easily. A regular system of pruning should then be established to develop a sturdy, well-spaced framework of healthy branches with an open canopy that allows air to move freely.
A study by University of Florida Professor Ed Gilman suggests reducing the size of the canopy by trimming the long side branches. When trees are thinned by removing the branches from the middle, the outer limbs grow too long and the weight is no longer distributed properly. These trees may become top-heavy and topple in the hurricane winds.
Some tree species stand up to strong winds much better than others. Although no tree can be guaranteed to stand up to hurricane force winds, the following varieties are more likely to withstand strong winds: geiger tree, mango, sapodilla, live oak, mahogany, tamarind and palms (which tend to flex with the wind, rather than snap).
There are also trees noted for dropping branches or splitting apart under stress. Losing leaves and twigs in a high wind will make a mess in the garden, but may give the trees an advantage by reducing stress on the main branches. Trees likely to lose major branches include gumbo limbo, eucalyptus, tabebuia and avocado.
Most species fall between the extremes and have a good chance of surviving a moderate to strong storm intact, provided they have had proper pruning.
The most wind-resistant form for a tree is with a central leader and a well-spaced framework of branches around and up and down the trunk. Most trees can be grown in this form when they are young, but the growth patterns of some species will change to a multi-trunk, spreading form as they mature.
There should be no narrow forks or branches leaving the trunk at an acute angle, because these branches are likely to split under stress. Crotches from 45 to 90 degrees are less likely to split than narrow V crotches of less than 40 degrees.
Young trees should not be cut back to make them bushy, but should be encouraged to form a strong leader, with well-spaced branches out to the side that are held back enough to stop them from forming multiple, competing leaders. A young tree can have the lower branches removed over a period of time to give a clear trunk to whatever height is desirable.
It should not be cleaned of laterals in the lower part of the trunk too soon, as the branches there will help give a larger trunk diameter and a much sturdier tree. Later pruning should consist of forming a well-spaced framework of strong branches and a pleasing outline to the tree. Remember not to let those branches become too long, lest you have a top-heavy tree.
Faced with a storm, gardeners who have kept their trees thinned and with a canopy in proportion to the trunk have little to do. For a neglected tree, severe surgery may be necessary. Begin by cutting out “sucker shoots” and cut out crossing branches or those growing into the center of the tree. Select a well-spaced framework of branches and cut the others out completely. Finally, trim branches to give the tree a balanced top.
As for palms, a practice called “hurricane cutting” is not a good idea. This practice involves removing not only the dead, brown fronds, but also beneficial green fronds, leaving only a few fronds sticking straight into the air, like a telephone pole.
Severe cutting of the fronds will stunt root growth, which in turn will stunt the tree’s growth and leave it susceptible to diseases and without a good root system to help it survive hurricane winds.
This practice also weakens the area surrounding the heart of the tree, making it more likely that the entire top of the palm will be torn off in high winds. Removing green fronds also reduces leaf surface area, which decreases the tree’s ability to harvest sunlight for more food. Palms also take moisture from the air through their fronds. Obviously, hurricane cutting of your palms only weakens them making them more susceptible to hurricane damage. Remember this rule – if the frond is green and not interfering with anything, leave it, because the tree is using it.
It is probably inevitable that someday, we will suffer another Hurricane Donna, Andrew or Wilma. Prepare your landscapes by properly pruning your trees and plants and you’ll increase the odds of keeping all of them intact.
Eileen Ward and her husband Peter own and operate Greensward of Marco, Inc., a lawn maintenance and landscaping company. Besides completing horticultural courses from the University of Florida, Eileen holds a commercial maintenance spray license and is a registered dealer in agricultural products in Florida.