Sulfite for Palm Trees

Deficiency

• As opposed to the more common nitrogen deficiency seen in the majority of other landscape plants, palm trees are more prone to suffer from a deficiency of potassium, manganese and magnesium. The manganese deficiency symptoms require the addition of manganese sulfate to the soil. Manganese sulfate is not the same thing as magnesium sulfate or Epsom salts that are used to correct a magnesium deficiency in the tree.

Symptoms

• Queen palms are among the most affected palm variety. The new leaves of affected trees are chlorotic or yellow and are smaller in size. There are necrotic streaks seen around the leaf veins. Unless corrected in time, leaves continue to get distorted and withered. Damage spreads to older leaves that may be completely withered and distorted. The condition is commonly referred to as frizzletop.

Causes

• Manganese deficiency is very common in palm trees growing in alkaline soils in which soil pH is over 6.5. Although the soil may contain enough levels of manganese, the high alkalinity reduces availability of nutrients to the tree. The deficiency also occurs in palm trees growing in cooler soils and in soils that are poorly drained. The fact that the symptoms appear first on new leaves isolates the disorder from an iron deficiency that also creates similar symptoms throughout the trees, but not starting from new leaves.

Remedy

• Add the required soil amendments to lower the pH level of the soil. Apply manganese sulfate in the form of foliar or soil fertilizers. The University of Florida Extension recommends keeping the palm tree well fertilized on a regular basis as it can take several years for a tree to recover from any nutritional disorder. Use a fertilizer specifically formulated for palm trees four times a year. Suggested application rates are 1 to 2 pounds for younger trees and between 5 to 8 pounds for older, mature trees.