Palm tree fronds come in a variety of shades of green and yellow-green, but regardless of the color, it should be consistent throughout the length of the frond. Yellow tips on a palm frond signals a problem. It could be caused by something simple, such as inadequate moisture, or serious, such as a disease.
The most common reason for yellow tips on palm tree fronds is inadequate watering. Although palm trees grow well in hot, sandy areas, they are not necessarily drought tolerant. If a palm tree does not receive enough water, it becomes stressed and the fronds begin to die back, starting with the tips, which will turn yellow and then later, brown. Most palm trees require a deep watering once per week. The top 2 inches of soil should be allowed to dry out, but soil below the 2-inch mark should stay moist.
Lethal yellowing is a disease that eventually kills the palm tree. It begins with yellowing of the fronds, starting with the ones on the bottom. The yellowing progresses upward through each frond and to the top of the tree until it kills the leaf bud. Progress of the disease can be slowed or controlled with oxytetracycline injections, but there is no cure. It is caused by phytoplasma, which is similar to bacteria, and it is believed that insects spread it. Prevent infections by choosing palm varieties that are resistant to the lethal yellowing.
Lack of proper nutrients in the soil can cause the tips of palm fronds to turn yellow. If a palm tree does not receive enough nitrogen, potassium or magnesium, it will show up in the color of the leaves. Apply a fertilizer designed for palm trees about three times a year. Once frond tips are yellow, it is too late to repair the damage with fertilizer, but it can prevent further damage. Look for a fertilizer that contains 10 to 20 percent nitrogen, 5 percent phosphorous and 10 to 20 percent potassium.
In addition to causing significant damage to the rest of the tree, freezing temperatures can ruin palm fronds, turning the tips yellow and brown. Palm trees do not tolerate cold weather or frost. In many cases, if the tree survives, the damage will last into the next growing season, with new leaves also displaying yellowed tips.