(See the pdf for illustrations)
Palms are a dominant part of south Florida's landscape and add a tropical image to this part of the state. Palms vary greatly in size from those that mature at a height of less than 3 feet with pencil-thick stems to monsters over 100 feet tall with trunks approaching 3 feet in diameter. Palms may be single-stemmed or have multiple trunks (clumping palms). Single-stemmed palms fit into small spaces better than most broadleaved trees because they do not branch. On the other hand, some clumping palms can become too large for typical residential landscapes. Palms may have feather-shaped (pinnate) leaves that impart a relatively fine texture, or fan-shaped (palmate or costapalmate) leaves that are very bold in texture. Some have rather rigid leaves, while others have weeping leaflets that provide additional interest in the landscape. Proper selection will ensure that the palm you plant will be appropriate for your particular site and desired effect.
Although most palms grow best in full sun, some are intolerant of direct sunlight and must be grown in shaded locations. Similarly, most palms are quite tolerant of both wet and dry soils once established. However, there are palms that cannot tolerate drought conditions and others that will not survive in very wet soils. When palms are to be planted near the coast, tolerance to salt spray is another important consideration when selecting palms. Palms listed as having high salt tolerance can be grown in exposed sites near the seashore, those with moderate salt tolerance must be planted in protected sites near the ocean, and those with low salt tolerance should not be planted within ¼ mile of the seashore.
Typically, palms will fare better in windstorms than broadleaf trees, but some are even better adapted than others. Proper palm selection will improve the chances of a palm thriving in a particular location. Table 1 lists a number of species that can be grown in south Florida landscapes. Although many other species have been successfully grown in south Florida, they are relatively rare in the nursery industry and thus are not readily available.
Palm Maintenance
Palms are often thought to be low maintenance plants in the landscape, but in south Florida's infertile soils, nutrient deficiencies are common and can result in unsightly deficiency symptoms or even death of a palm. Unlike broadleaf trees that usually grow well without fertilization, most palms in Florida landscapes require supplemental fertilization with an appropriate palm fertilizer to prevent or treat these deficiencies. For information about palm nutrient deficiencies and proper fertilization see EDIS publications EP273 Nutrient Deficiencies of Landscape and Field-grown Palms in Florida and EP261 Fertilization of Field-grown and Landscape Palms in Florida.
Another maintenance consideration is whether a palm is self-cleaning or not. Many tropical palms have tightly clasping leaf bases that form a smooth green stem-like area just above the true trunk called a crownshaft. Palms with crownshafts that do not have extensive potassium deficiency symptoms are self-cleaning. That is, old senescing leaves will fall off cleanly by themselves. When old leaves of non-crownshaft palms senesce, they will simply hang down against the trunk and must be manually cut off. It is important to note that half-dead or discolored older leaves that remain on a palm for several weeks or longer are probably exhibiting symptoms of potassium deficiency (see EDIS publication EP269 Potassium Deficiency in Palms) and not natural senescence. Natural senescence of healthy old palm leaves takes only a few days for a leaf to turn from completely green to uniformly orange-brown and finally completely dead.
Insect Problems
Although most insect pests have a minor impact on palm appearance and health and are not particular about which palms they feed on, there are some exceptions. A few palms are particularly attractive to some insect pests that can become debilitating or even fatal to the palms.
Other Considerations
In addition to palm physical appearance, susceptibility to disease or insect problems, and adaptability to a particular site, other attributes may also be important, especially if small children are present. Many palms have sharp spines on their petioles or trunks that can be quite dangerous. Others have fruits that contain high concentrations of skin-irritating chemicals. Such fruits should not be handled unless rubber gloves are worn.
Planting
Palms may be planted during any season of the year, but the warm, rainy summer months are best. Small, container-grown palms of any species can be transplanted easily. However, some species such as Archontophoenix spp. are notoriously difficult to transplant from field nurseries.
Follow the steps below when planting a palm:
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Dig the hole at least 6 inches larger in diameter than the root ball to ensure that the backfill soil will be in contact with the entire root ball. The hole should be deep enough so that the top of the root ball of a field-grown palm is even with the surface of the ground. For container-grown palms, make sure that the base of the stem (if visible) is about an inch below the surface of the soil.
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Amending the backfill soil is not recommended.
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Gently position the palm so that it is upright, and fill around the root ball with soil. Water thoroughly to remove any air pockets.
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Form a basin with soil around the perimeter of the root ball to retain water during irrigation.
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Support large trees with braces to maintain stability during the first 6 to 8 months. Nails should not be driven directly into palm trunks.
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Water daily for the first few weeks and frequently thereafter until the palms are well established.
For additional information on planting palms see EDIS publication EP001 Transplanting Palms.