|Queen palms leaves are browning and drying. two of three are this way. lawn has an irragation system every two weeks. trees are ten years old.
|It's not clear from your question, but if the only water the queen palms are receiving is from the lawn irrigation, that's your likely problem. It's probably a combination of inadequate water and salt burn. When leaves brown around the edges, the problem is often salt burn. This is common in our area with low rainfall, alkaline soil and water high in salts. Frequent, light "sprinklings" or short time spans with drip irrigation, allow salts to accumulate in the top layers of soil, where the roots absorb it, which is bad news. Browning usually occurs on the old leaves first. This excess salt accumulates in the leaf edges, where it kills the tissue and the leaf dries out and turns brown. It's important to water deeply, slowly and usually infrequently as possible for landscape plants. Lawn systems are not timed to run long enough to provide a slow, deep watering for landscape plants, nor should they be, or the turf will be overwatered, becoming susceptible to fungal diseases and other problems. If you don't have irrigation on the palm, use a hose with a slow trickle, or fill its watering well and let it soak in. Water should penetrate 2 feet deep. Use a pointed stick or piece of metal to push in the soil. It will move easily through moist soil and stop at dry soil.
Similar symptoms occur when these palms suffer from iron or manganese deficiency. Iron chlorosis is common in non-native plants, because although iron is available in the soil, the alkalinity makes it difficult for non-adapted plants to use it. Chlorosis appears as yellowing fronds that may turn brown. You can apply a chelated iron source now, but it's generally not advisable to fertilize landscape plants in our summer heat. Plant roots often "burn." Apply a fertilizer formulated for palms (it will have the appropriate micronutrients) in mid spring and again in early summer. Water immediately to a depth of 2 feet.
Finally, I know queen palms are sold at our local nurseries, but they are actually a palm that is not well-suited to our growing conditions. In addition to the above problems, fronds take a beating in our wind and arid conditions. I hope this information helps!