Palm Tree Deficiencies and Fertilization

What to do this week –
By Mark Govan, Host “Florida Gardening“

Palm Tree Deficiencies and Fertilization
Palm trees are a great addition to any landscape. Their beauty and stature can give your home that “Florida feel”. Some palms can be used as a privacy screen, while others may be used as small specimen plants to enhance the landscaping. Some property owners purchase large stately palms to showcase their homes. Unfortunately, many palm species need special fertilizers and micro-nutrients to keep them healthy and vibrant. In this article, I want to cover a few of the more common species of palms we grow and what you need to do to keep them looking great. Let’s get started.

One of the common palms found in landscapes is the Phoenix roebelenii or Pygmy Island date palm. Pygmy date palms are normally used as an accent plant or to limit the street view into homes. Because this palm matures at six to eight feet in height, they are very easy to work within the landscape. You can find single, double or triple trunked pygmy date palms depending on the look you want to achieve. Although they are versatile, these palms tend to show a yellowing of their lower fronds, which is unsightly.

Yellowing of the oldest fronds comes from two different problems; neither of these involves insects nor diseases. These problems are caused by a lack of nutrients in the form of potassium and magnesium. Before you go out and buy a fertilizer, you will need to read on. Please look closely at the lower fronds of your plant. If the lower fronds are yellow, and the tips at the ends of the fronds are necrotic or look dead, then the problem you have is a potassium deficiency. If you look at the lower fronds, and the centers of the fronds are green and the outer portions are yellow, but do not have that dried-out necrotic look, then you have a magnesium deficiency.

Although these problems are very close in appearance, you must know which element is needed in order to cure the problem. There is also one thing you must not do if your pygmy palm is exhibiting either of these problems. Do not prune off the lower fronds from the palm. Pruning the bottom fronds will only remove a much-needed food source of the plant. As nutrients are depleted from the top growing portions of the palm, necessary minerals are drawn from the lower fronds to feed the new growth. I will discuss how to fertilize your palm later in this article.

Please do not assume these nutritional deficiencies are the same on all palms. The Phoenix canariensis or the Canary Island Date palms have similar problems with yellowing leaves. However, the lower leaves will be strictly potassium deficient without showing the necrotic tips on the leaflets. Mid-range fronds on these palms show magnesium deficiencies as a dark-green center next to a distinctly yellow outer portion of the leaf. Although these problems are similar to the Pygmy palm, sometimes subtle differences can mean the difference in either correcting or prolonging your problem.

Another deficiency which not only affects the Pygmy palm, but also many of the other palms we grow in Central Florida, including the Queen Palm, Foxtail Palm, and Royal Palm, is a problem called “Frizzle Top”. Frizzle Top is caused by a deficiency of manganese.