Palm trees will quickly let you know when they’re unhappy. Different species of palms display different symptoms, so knowing which species of palm you have is important. A Garden Center associate can help identify problems and suggest the best solution for your tree.
The problem could be too little or too much fertilizer. Signs include leaf wilt, orange or brown spots, yellowing leaf tips, entire leaves withering and dropping off, or abnormal new growth. Remember to always use controlled-release fertilizers that won’t leach through the soil during the next rainstorm.
How to Treat Common Palm Nutrient Deficiencies:
- Potassium (K): The most common nutrient deficiency in palms is potassium, and it is the most serious. Yellow or orange speckles appear on leaves or along the margins and gradually the leaf withers and dies. It starts on older leaves and if left untreated, appears on new growth. Affected leaves do not recover. Treatment: Apply sulfur-coated potassium sulfate according to directions. Too much potassium can cause an imbalance of magnesium, so apply the recommended amount of magnesium at the same time.
- Magnesium (Mg): Fortunately, magnesium deficiency rarely kills a palm. The oldest leaves on a palm will turn yellow along their edges, while the center of the leaf remains green. This will progress to younger growth if left untreated. Treatment: Which fertilizer to use depends on whether the soil is acid or alkaline. A small amount of potassium may need to be applied along with magnesium to prevent an imbalance, as in the potassium treatment above.
- Manganese (Mn): Manganese deficiency can be fatal to many species of palms. New leaves appear scorched, frizzled, or have long dead streaks. It’s usually caused by high pH levels. Treatment: Apply manganese sulfate to the soil or spray it on the leaves.
- Boron (B): Symptoms of boron deficiency only appear on new growth. Leaves are sharply bent at the tips, or are small, deformed or fused together. Treatment: For a medium-to-large palm, dissolve 2-4 ounces in 4-5 gallons water. Pour slowly over the roots under the palm canopy. Too much boron can harm the plant, so be careful not to over-apply.
- Nitrogen (N): This deficiency is relatively unusual in palms in the landscape, but occurs in container plants. It’s easily fixed. Symptoms include a lack of vigor and leaves that are light green instead of dark green. Treatment: Apply a nitrogen fertilizer to the soil to quickly darken the leaves.