Most Common Nutrient Deficiencies of  Palms  

The most commonly deficient nutrients are listed below. Symptoms of deficiencies on palms may be difficult to diagnose since they are often different than on other plants, and symptoms of several deficiencies may overlap. Symptoms are the same whether the plant is container-grown or in the landscape although the causes may be different. An excellent color reference on nutrient deficiency symptoms in palms is Diseases and Disorders of Ornamental Palms (edited by A.R. Chase and T.Y. Broschat and available from the American Phytopathological Society, St. Paul, MN).   

An overall and uniform light green color and a decrease in growth characterize nitrogen deficiency. It is relatively easy to correct with application of nitrogen fertilizers. Nitrogen deficiencies may be fairly common in the landscape, especially on light or sandy soils, but deficiencies of other elements such as potassium, magnesium, and manganese, can be much more prevalent and severe. Nitrogen is the nutrient most commonly deficient in container-grown palms.  top of page  

Recent research has revealed the important role of potassium in a well balanced nutrition program for palms. Palms need potassium in large amounts, equivalent to that of nitrogen. Yellowish or orange flecking or spots which are translucent, mottled or discolored pinnae, and tip and/or marginal necrosis characterize potassium deficiency on palms. Symptoms appear on the oldest leaves first but newer leaves will be affected as the disorder becomes more severe. Affected leaves will not recover; the palm must produce a new crown of new, healthy leaves 

Potassium is highly soluble and readily leached from light, sandy soils and container media subjected to heavy, frequent irrigation. In fact, potassium deficiency can be the most widespread and sever disorder of palms. Chrysalidocarpus Lutescens (Areca palm), Caryota spp. (Fishtail palms), and especially Howea Forsterana (Kentia, Sentry palm) seem to be susceptible to potassium deficiency during container production. 

The use of fertilizers with controlled- or slow-release nitrogen and water soluble potassium accentuates potassium deficiency on sandy soils and in container media. While the nitrogen supply will last for several months or more, heavy rain or one or two irrigations will leach the potassium completely from the soil. 

Heavier landscape soils can retain potassium against leaching, hence potassium deficiency is less common in palms in the landscape, especially where soils are heavier. Potassium deficiency in these cases is usually due to low potassium content of the fertilizer or inadequate fertilizer or inadequate fertilization. Palms planted in or near lawn areas often exhibit potassium deficiency due to heavy, frequent irrigation and use of fertilizers high in nitrogen but with little or no potassium. 

Symptoms of potassium deficiency are not uncommon on landscape plantings of Syagrus (Arecastrum), Romanzoffianum (Queen palm), Butia Capitata (Pindo palm), Rhaphis spp. (Lady palms), Brahea spp. (Fan palms), Trachycarpus Fortunei (Windmill palm), and Sabal spp. (Palmetto).  top of page  

Palms are heavy users of magnesium and deficiencies are frequently seen in palms on sandy soils. As in potassium, symptoms of magnesium deficiency appear on oldest leaves first and progress up the canopy. 

A broad yellow band around the margin of an otherwise green leaf characterizes magnesium deficiencies. Landscape planting of Phoeniz spp. (Date palm), Syagrus (Arecastrum, Romanzoffianum (Queen palm), Butia Capitata (Pindo palm), Livistona spp. (Fountain palm), Trachycarpus Fortunei (Windmill palm), and Sabal spp. (Palmetto) occasionally display classic symptoms of magnesium deficiency in California. 

Treat palms preventively for magnesium deficiency since affected plants are slow to respond to post-symptom treatment. Affected leaves will not recover and the plant must replace them with new, healthy ones, a process that could take as long as two years. 

The use of sufficient quantities of high grade dolomite in the potting mixture and soil applications of magnesium sulfate at the rate of 1-2 kgs. (2-4 lbs.) per tree plus controlled-release potassium four times a year to palms in the landscape should prevent magnesium deficiency.  top of page  

Symptoms of manganese deficiency appear in the newest leaves first. New leaves are chlorotic, weak, reduced in size, and/or have necrotic streaking. As the deficiency progresses, new leaves emerge withered, frizzled, or "scorched", finally appearing only as necrotic petiole stubs. 

Manganese deficiency is primarily due to the element's insolubility of high pH, making it unavailable in plants. Due to the high pH of alkaline soils, manganese is one of the most frequent deficient elements of palms in southern Florida and, to a lesser extent, in southern California. In Florida, the deficiency is called "frizzletop" because of the frizzled look of the new leaves. 

Adjusting soil pH, applying manganese sulfate per 3.8 liters of water (1 teaspoon/gallon), or applying manganese sulfate to the soil 2-3 times a year should correct the deficiency and prevent its recurrence. 

Manganese is usually not deficient on container-grown palms since the element is more available at the lower pHs of potting mixtures. However, poor drainage and/or cool soil temperatures during winter that result in reduced root activity and uptake of micronutrients may cause manganese deficiency, particularly in soils where the element is already marginally deficient. 

Frizzletop will occur as air temperatures rise in spring and growth of foliage commences yet roots are still inactive in the relatively cool soil. Soil temperatures finally rise and root activity increases.
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Symptoms of iron deficiency, as in manganese, appear first on the newest leaves. Intervenal chlorosis, tip necrosis, and stunted new leaves characterize iron deficiency. Iron deficiency in palms is not due to a lack of iron in the soil, and rarely is it due to high pH, as in many other plants. 

Iron is nearly always present in the soil in sufficient quantities; it is mainly poor aeration that causes deficiencies of this element. 

Waterlogged and poorly aerated soils, or palms planted too deeply are the primary causes of iron deficiency. 

Foliar sprays of 2.5 ml. iron sulfate or chelate per 3.8 liters of water ½ teaspoon/gallon) may offer temporary correction; poor aeration or improper planting depth must be corrected or the problem will continue to recur. 

Preventive treatment by planting and repotting at the correct depth in a well drained soil or potting mixture is the only permanent solution for iron deficiency. Also, dibble, rather than surface apply fertilizers to containers and use a potting mixture that is resistant to rapid breakdown.  top of page  

Symptoms of sulfur deficiency are similar to those of iron. Sulfur deficiency is uncommon in palms and would probably only occur in container-grown palms when sulfate fertilizers are not used. 

Deficiencies of phosphorous, calcium, copper, zinc, boron, and chlorine rarely occur if one adds dolomite and micronutrients to potting mixtures and uses a complete, controlled-release fertilizer. Boron toxicity could be a problem in areas where irrigation water contains high amounts of this element.

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