Planting a Palm Tree
Dr. Henry M. Donselman, Palm Specialist
Palms are one of the most important components of tropical and subtropical landscape. They present a tropical look that no other material can provide. Fortunately many palms are well adapted to the soils in the warmer parts of the United States and require a minimum of care to establish and maintain properly. The initial care you give your palm when transplanting it often determines the future success of the plant in the landscape.SITE SELECTION AND PREPARATION
Several factors should be considered before selecting the planting site for a palm. If you have a specific type of palm in mind, be sure to consider how the plant will fit in the landscape in 10-15 years, when it reaches maturity. Are there overhead utility wires, buried cables, or irrigation lines? Would the palm pose a hazard during a hurricane? Is the sun exposure full, partial, or shade? As a general landscaping rule, small lots with one story houses look best with medium sized or smaller palms. Large palms such as Dates (Phoenix sp.), Mexican Fan Palms (Washingtonia robusta), and Coconuts (Cocos nucifera) look best when planted in large areas or in the vicinity of larger buildings. Clusters of odd numbers of palms (1, 3, 5) are generally more aesthetically pleasing than even numbered groups, unless more than seven are being planted in one area.Consideration should be made of the type of soil the palms will be planted in. Is it alkaline sand, coral rock, clay, marl, or another soil-type? By knowing the soil-type, it is often possible to predict certain nutrient deficiencies and correct them preventively rather than after the problem shows up.PREPARING THE SOIL
For many years, it was felt necessary to amend poor soils with organic material. Current recommendations discourage the use of soil amendments (such as peat moss) mixed with the back fill. The ideal situation is to have the whole planting area rich in organic material; if the planting hole is filled with soil much better than that around it, the roots may never penetrate the surrounding poor soil. Note that in California pure washed plasters sand is often the only backfill used when planting Date palms, especially the valuable Canary Island Date. This works well with these palms as long as drainage of the planting pit is perfect.It is much more important that you apply a heavy mulch around the trunk, using wood chips, cypress or redwood bark, or other similar material. As this decomposes, it enriches the soil while also reducing the weed competition and reducing water consumption. Be sure to replace the mulch as it decomposes. Keep a small circle (several inches) around the base of the trunk free of mulch.WATERING
Water the backfill of the palm with a hose as it is being planted. This will ensure that no air pockets are trapped in the soil and will establish a good union between the root ball and the existing backfill and soil. After planting, a small (4-6 inch high) soil "dam" encircling the plant will direct and concentrate future watering to the root ball of the palm. Watering for the first several months is critical. Never allow the soil to dry out completely. It is also important not to overwater. Overwatering not only encourages root diseases, but it also discourages the establishment of new roots in the surrounding soil. I often recommend Toro DL 2000 (laser tubing) as a temporary irrigation system installed using several wraps of this tubing around the palm trunks directly above the rootballs. I recommend this relatively inexpensive, method of applying water to newly installed palms or palms in planters. This consists of black flexible polyurethane pipe on the soil surface (or shallowly buried with mulch) and several wraps of this tubing around each palm trunk. This small diameter laser tubing has a large number of precise holes along its length. Knowing the output of the tubing/foot and the length of time the water will be turned on, one can accurately determine the number of wraps needed for each palm. Generally after 18 months the palms are switched over to a permanent irrigation system.TIME OF THE YEAR TO TRANSPLANT
Palms can be transplanted at any time of the year although they establish themselves far more quickly and with fewer problems if they are set out in the spring and summer. Palms do not grow as rapidly during the winter months and several experimental observations have shown that cold-damage is much more severe in palms that are not well established. Check here for more information about the time of year to plant palms.FERTILIZER
To establish a palm rapidly, a good fertilizer program is necessary. For the first year, a foliar micro-nutrient spray applied every three to four months and a slow release granular fertilizer with a 3-1-3 ratio of nitrogen, phosphorus, and potassium applied every four months will provide the optimum results. After the first year, only the granular fertilizer is required.OTHER FACTORS
If you purchase a field-grown palm that has been "balled and burlapped" but is not to be planted out immediately, it is important to store the palm properly. Most palms can remain out of the ground for two to three days with no damage if they are kept in a shady area and the root ball is watered daily. Desiccation of the root ball will severely damage the palm and reduce its chances of proper establishment. When planting a "balled and burlapped" plant as opposed to a containerized one, it is necessary to remember that the plant is more likely to suffer from transplant shock since the root system has been severely reduced. Also, one should pay particular attention to the burlap surrounding the roots. If, after planting, a portion is exposed to the air it will act as a "wick" drying out the soil and stressing the roots. Complete coverage of the root ball and a heavy layer of mulch will alleviate this problem.Many palms also suffer from being planted too deeply. This essentially suffocates the roots and invites root diseases. As a general rule, one should always plant a palm at the same depth as it was initially grown.There are so many palms ideally suited for the warmer climates of the United States and provide much of the unique environment for which these states are known. Look around in your neighborhood to get a good idea of what will do well for you, and ask your local nursery person. Because of their relative ease of culture of palms and their minimal pest and disease problems, they should be prominently displayed in our landscape. By observing the recommendations presented here you can make palm trees an important part of your landscape.
