Palm Tree Leaves Turning Yellow | Causes and Solutions

When healthy and thriving, palm trees are magnificent plants. Whether climbers, shrubs, or tall slender trees, palms, with their varied structures and form are thought to be one of the oldest living arboreal species. 

As exotic as they appear, there is nothing to stop you from growing palm trees no matter where you live since they can withstand cooler temperatures and are even tolerant of heavy rain. 

Chances are you already know that yellowing leaves on palm trees are not a good sign, but knowing what the reason is and how to fix it is not always simple. 

In this article, I’m going to be explaining what causes palm tree leaves to turn yellow and provide you with the tools to need to identify the cause for yourself, as well as fix and prevent them too.

Why Are My Palm Tree Leaves Turning Yellow?

Well firstly, palm trees need essential nutrients in the soil. Among these are nitrogen, manganese, and magnesium. A deficiency or imbalance of these nutrients will reflect in the leaves and is a primary reason for leaves turning yellow. 

Other causes of yellow leaves are watering problems, fertilizing issues, fungus, insect attack, or transportation-induced trauma. Most of these issues can be remedied if dealt with in good time. 

Here is a look at each of those reasons in more detail as well as tips for treating the problem and preventing it from occurring in the first place.

Nutrient Deficiencies in Palm Trees

With insufficient nutrients, your palm may develop yellow leaves, fungi, and leaf spots. The symptoms will appear worse on the tips and edges of the leaves and may extend to necrosis (tissue death).

As the plant’s undernourishment continues, your palm may display yellowing between the veins, and even deformity of leaves which is indicative of manganese deficiency and marginal chlorosis on the older fronds. 

With an iron deficiency, the young leaves will be yellow with green veins. And if it has a potassium deficiency, the older leaves will have yellow spotting. 

Fixing Nutrient Deficiencies

Planting your palm in well-draining and nutrient-rich soil will help prevent these leaf issues from occurring in the first instance. 

However, when it does happen treatment and preventative measures can be successful once you have conducted a soil pH test to identify the specific nutrient deficiency. 

I recommend only fertilizing during the active growing season using a slow-release fertilizer with an NPK ratio of more nitrogen and potassium compared to phosphorus. I use a 3-1-3 but you could also use 6-2-6 or 10-0-8 depending on your soil pH and the results of a test. 

The fertilizer you choose must have a lower ratio of phosphorus. High amounts of phosphorus will inhibit your palm from absorbing other micronutrients such as iron, manganese, boron, and magnesium.

Nitrogen Deficiencies in Palm Trees

Nitrogen is one of the most important plant nutrients and a deficiency manifests in the form of a golden color near the base. It will begin with a pale-green discoloration spread evenly throughout the oldest leaves and progress to younger ones. 

Unfortunately, nitrogen is extremely soluble in soil, which means it is easily leached out during heavy rain or over-watering. 

Treating Nitrogen Deficiencies 

To fix a nitrogen deficiency in your palm tree soil, apply a fast-acting and high-nitrogen feed in early spring. Conduct a soil pH test a month later to see if further applications are required.

Palm tree

Magnesium Deficiencies in Palm Trees

Although a secondary deficiency amongst palms, it is easy to spot the impact of a magnesium deficiency because of the appearance of bright yellow just at the tips. 

Another common manifestation of magnesium chlorosis is yellowing on the surface of the leaves, regularly appearing in broad bands. 

If you see these symptoms on leaves that are lower down on the canopy, you can be sure that your palm has suffered a magnesium deficiency in the past. 

Simply testing the soil may not always prove useful because the nutrient profile given is not always indicative of the plant itself and its state of health. 

Treating Magnesium Deficiencies

However, as palms are very much in need of magnesium, in addition to your regular fertilizer, two or three sprinkles of Epsom salt around the base of your palm will be a welcome boost for roots to absorb with visible benefits often seen quickly. 

Excessive Fertilizer

Did you know that it is possible to kill a tree by applying too much fertilizer? Lavishing large quantities of quick-release high nitrogen fertilizers into the soil can burn the roots and likewise, the foliage if sprayed or drenched over it.

Even fertilizing surrounding trees, shrubs, and lawns can be a cause of overfertilizing issues. In particular, avoid using a high-nitrogen turf fertilizer within 50 feet of your palm as this.

Avoiding Over-Fertilizing Issues

The University of Florida recommends fertilizing your palms three times a year, spring, summer, and fall with a quality slow-release 10-0-8 NPK formula if you want to keep your trees green and healthy.

Avoid too much potassium and phosphorus in your fertilizer because your palm tree simply may not be capable of tolerating it and any overload will stifle its ability to effectively absorb other vital nutrients including calcium, zinc, and copper. 

Watering Issues

Palm trees are generally easy to maintain, but a common mistake palm owners make is failing to strike the right balance when it comes to maintaining their water levels. 

A palm tree’s requirements when it comes to H20 tend toward the higher end of the scale, but too much can cause leaf wilting and a fungal infestation, so hitting the right spot is imperative and will depend upon the size of your palm and where it is located. 

There are many effective methods you can employ when gauging the perfect time to water. From merely observing the dryness of the leaves to weighing the pot after watering and re-weighing after a few days, and comparing the difference. Only when there is a large discrepancy between weights will the palm require more water. 

If your palm is planted into the ground directly, be on the lookout for moisture problems such as delayed development, yellow or brown tips on the leaves, or a trunk that feels almost hollow. 

I like to keep my watering regime simple. I check the dryness of the soil halfway down the pot (or the top 4-5 inches of soil if planted in the ground), and if it’s dry I’ll give my palms good water. If the soil is still moist I’ll check back again in a few days.

As with most plants, your palm will need more water in the summer months when the weather is warmer and moisture is absorbed or evaporated quicker. It will need significantly less water in the winter and when the weather is cooler when it is growing.

Underwatering Palm Trees

An underwatered palm tree will soon show you the stress it is suffering with outward signs such as yellow, drooping, and dry leaves. 

Low humidity and a lack of water will create what are essentially drought conditions as your once luscious palm is parched. 

Fixing Underwatered Palms

To revive an underwatered palm, you will need to aim to recreate the conditions of its native environment. This means regular misting of the leaves as well as watering of the soil more frequently. Only then can you begin to restore your withered palm. 

Other factors to check for when growing indoor palms are positioning it too close to a heating system, draughts from air conditioning or windows, and soil around the root ball which has completely dried out. 

Over-watering Palm Trees

An overwatered palm tree is going to change from vibrant and thriving to yellow and wilting pretty quickly. 

Pale yellow and limp leaves, plus black roots are sure signs of overwatering. The leaves may curl at the tips and edges and the older leaves may turn yellow and brown before dying altogether. 

There are some methods to help prevent this disaster from happening and steps that you can take to remedy the situation if it has already begun. 

Fixing Over Watering Issues

If your palm is already showing signs of overwatering, all is not lost. Firstly and most obviously, stop watering your palm.

For in-ground planted palms, mixing sand with the soil will help improve drainage. Alternatively, consider installing a drainage pipe that can help to take water away from the roots.

For potted palms, remove them from the pot and see if there are changes to the root ball. Remove as much soil as possible from the roots and then prune any rotten parts to encourage regrowth. Allow the roots time to dry out in a warm and dry spot before starting to re-pot.

When you’re ready to return your palm to its pot always use fresh potting mix combined with sand and gravel to act as extra drainage. 

To begin with, you can move your palm to a shady area which, although appearing counterintuitive, will help it use less water. You may place it back in its usual light when it is showing signs of health.

Resume a less frequent watering schedule and only water when you are sure the top half of the potting mix (or the top 4-5 inches of soil if planted in the ground) is dry.

Fungal Disease And Pests

Overwatered soil creates the ideal breeding ground for the proliferation of fungi. 

One of the most common of these infections is Fusarium wilt. This fungal disease is caused by a specific species named Fusarium oxysporum. This common and fatal fungus attacks the palm tree through the soil and travels upwards into the roots spreading to the palm leaves. 

According to the University of California, once infected, your palm tree will soon display symptoms including the yellowing of leaves, just on one side and typically on older and lower leaves plus a diminished canopy. 

Fixing Fungal Infections

Fungal diseases can be prevented by avoiding overwatering and only watering when the top 4-5 inches of soil (or half of the pot) is dry. 

Regularly check the plant for the telltale one-sided yellowing of leaves and take action immediately if you suspect a problem. 

To fix fungal diseases on your palm, prune away the infected fronds with disinfected sheers, and be sure to disinfect all implements after use. Take care to dispose of the debris and do not compost any diseased fronds.

Apply fungicide to prevent it from spreading to healthy leaves. As a precaution, spray fungicide on any wounds or damage caused to the trunk and bark.

For potted palms, sterilize a new container using 1 part bleach to 9 parts water. Make sure that the pot is a good fit with one to 2 inches more room than the diameter of the roots. Beware that too much root space can also be a breeding ground for fungus. 

Repeat fungicide treatment every 2 weeks to control any remaining root rot and periodically observe the roots for signs of disease. 

Use a fertilizer that will give your diseased palm a much-needed boost of nutrients to kick start. 

If the fungal disease continues, dispose of the entire plant to prevent it from infecting other plants.  

Ganoderma Zonatum (Butt-Rot Fungus)

Ganoderma zonate, most commonly known as butt-rot fungus, is most readily observed in the base or ‘butt’ area of your palm tree, where airborne, microscopic spores invade via wounds most often caused by strimmer blades or lawn mowers. 

Mild to severe wilting of almost all the fronds is a sure sign but may be accompanied by overall decay and yellow discoloration.

Monica Lynn Elliot, professor of the Plant Pathology Department at the University of Florida has detailed the numerous enzymes responsible for this degradation.

Be aware that these symptoms in isolation are not sufficient for a diagnosis of Ganoderma butt rot. The spread of this fatal fungus is helped along by spores that germinate once landing on the soil and trunk wounds.

Fixing Butt-rot Fungal Infections

Be sure to spray fungicide on any wounds or damage caused to the trunk and bark as soon as it appears.

Very early detection can prove vital in saving your palm tree if there is still healthy growth but once you start to see a ‘conk’ (structures of the fungus that produce spores) on the bark of the palm, it is generally impossible to save and must be removed from the area to avoid harming other trees. 

There are several methods that can be used to remove the tree, however, if it is mature and established you may need to kill the palm tree completely either by cutting it down or by using chemicals before removing the stump.

Be careful of how you dispose of the infected palm when you take it to a landfill or use an incinerator. 

Of course, avoiding injury to the palm and not planting any other palms close by where they are likely to be invaded is a necessary precaution. 

Bob Peterson
A cabbage palm with Ganoderma zonate, (butt-rot fungus)

Palm Aphids

Two aphids are known to infest palms are Cerataphis brasiliensis (Hempel) and Cerataphis lataniae (Boisduval). Unlike a typical aphid, palm aphids look like a whitefly or scale insect. 

When this pest attacks a palm tree, it will stunt the growth, causing its leaves to turn yellow or speckly as the aphids suck vital nutrients from the plant. 

Palm aphids are known to especially attack new growth and leave behind a waste product which then attracts ‘sooty mold’ fungus to the leaves.  

Getting Rid of Palm Aphids

In most cases, palm aphids won’t kill the plant but they can severely hinder its progress so you will want to prevent them by washing leaves weekly and wiping them with neem oil. 

A spray bottle containing water and a small amount of dish soap will help as the soap dissolves the outer layer of aphids and will eventually kill them. 

Aphids will not do much damage immediately so this gives you time to intervene. If your palm is outside, using a garden hose to blast the surface area will remove flying insects. 

Be sure to periodically check your palm trees for recurrence of aphids, and wipe them down with neem oil solution by-weekly. 

Black Bean Aphids

This small insect is common during warmer months and can infest a wide variety of plants and trees. 

Not only can they cause the yellowing of leaves, but they can also distort roots and cause poor growth as they suck out large amounts of sap. They can also spread up to 30 different viruses. 

Black bean aphids, aphis fabae, are easy to spot because their color contrasts so starkly with their host. You can find them on the stems and undersides of your palm.

Getting Rid of Black Bean Aphids

Luckily, these little visitors are fairly easy to treat with an insecticide. Choose one with a pyrethrum base or essential fatty acids if you prefer a more natural solution. 

Alternatively, a soap and water mixture is the simplest and most humane way to remove black bean aphids as it will simply dry them out. 

Whichever method you choose, remember to protect neighboring plants until the problem is solved and be vigilant in identifying them early on as prevention is by far the best mode of action. 

Black bean aphids

Citations

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Ben's horticultural interest grew when graduating from Hertfordshire University in 1997. Having contributed to numerous publications including Better Homes & Gardens, Garden Design Magazine, and The English Garden. He is also the author of Propagating Houseplants Made Easy.