Plumeria Leaves Turning Yellow? | Causes and Treatment

The plumeria plant, more commonly known as frangipani or Hawaiian lei, is a tropical flowering plant species, with beautiful waxy pinwheel-shaped flowers.  

Like all plant species, the Plumeria is susceptible to poor conditions, which often leads to the leaves turning yellow and often curling or dropping. This article aims to explain the most common causes of plumeria leaf yellowing and offer ways to solve them.

Why Do Plumeria Leaves Turn Yellow?

All photosynthesizing plants contain chloroplasts that convert sunlight into energy which the plant then uses to fuel cell reproduction and growth. 

The chloroplasts contain a pigment called chlorophyll, which gives leaves their green luscious color. When the plant conditions become sub-optimal the plant cannot produce sufficient chlorophyll and the leaves turn yellow, from a condition called chlorosis. 

A number of factors can lead to chlorosis in plumeria, including overwatering, nutrient deficiencies, and incorrect soil pH. I will cover and explain the causes of yellow leaves and what you can do to fix them. 

Plumeria is one of a number of native trees in Hawaii, America, Mexico, and the Caribbean so enjoys tropical and subtropical climates USDA Hardiness Zones 10B-11

Plumeria Leaves

What Causes Plumeria Leaves to Turn Yellow?

If your plumeria is showing yellow leaves, it is a sign that your plant is unwell and unhappy. As there can be a few reasons for this, you should aim to identify the specific cause and rectify the problem as soon as possible. 

Seasonality

Plumeria is a deciduous plant, which means its leaves will naturally turn yellow and drop off during late fall. Leaving the plant dormant over winter storing its energy ready to bud in spring. 

So, there is no need to be concerned if your plant leaves are yelling as the fall approaches, this is absolutely normal and part of the plant seasonal cycle. 

However, yellow leaves during the summer months can be a cause for concern. So Let’s cover the most likely causes.  

Overwatering 

Overwatering is arguably the most common cause of yellowing leaves among all plants and plumeria are no exception. As a plant that enjoys free draining soil, when Plumeria becomes waterlogged there is a lack of oxygen around the root system and root rot can set it. 

Root rot is often the result of stagnant standing water and bacterial or fungal infections. In some cases, it can be a combination of the three. 

Root rot can be identified through symptoms of yellowing leaves leading to soft foliage material. If left untreated, root rot will set in the foliage, causing plumeria stems to turn brown and eventually black. 

To treat an overwatered plumeria suffering from root rot, you should remove the plant from its pot, brush off the soil to expose the roots, and then wash off any excess soil under running water. 

If root rot is the cause of your yellow leaf problem, it will be easy to diagnose from the soft mushy roots, that have turned black and smell rotten.

To fix root rot, you will need to allow your plumeria to fully dry before repotting it with fresh soil. Be sure you to a container with sufficient drainage holes. 

If your plumeria is planted in the ground, you must improve the drainage by addition or sand or grit into the soil or simply refrain from watering it. 

Potted plumeria likes to dry out between watering, so push your finger into the potting soil, and check that the top few inches of soil are dry before watering. 

Underwatering

Being native to tropical regions, plumeria is a fairly hardy and drought-tolerant plant. Nonetheless, they can still be underwatered and symptoms manifest themselves in a number of ways.

Underwatered plumerias can be distinguished by their dry and yellow leaves that will eventually turn brown. The leaves will most likely also curl at the edges and have a crisp feel when touched. A plumeria with too little water is also likely to appear droopy or wilted because without sufficient water the leaves and stems cannot remain erect. 

Although plumeria dislikes their soil being soaked, if it is bone-dry most of the way through, this can be an indication it needs to be watered. Avoid regular watering, do water it with a soak and drought approach.

To treat an underwatered plumeria, simply water it immediately, but be careful not to overwater it and ensure you have sufficient drainage. Your plumeria plant should soon recover and grow new green supple leaves. 

Soil pH

Plumeria is able to survive a fairly wide range of soil pH, but this doesn’t mean they will thrive in them all. The ideal soil pH for plumeria is between 6.5 and 7.0 as they prefer slightly neutral to slightly acidic soil. This pH range helps plumeria to absorb phosphorous.

Phosphorous is an essential element required for root growth, seed size, and flowering in plumeria and other plants alike. An abundance of soil organisms and organic matter can also aid the uptake of phosphorous in plumeria.

Symptoms of incorrect soil pH vary depending on whether the soil is too acidic or too alkaline, as this affects the uptake of essential nutrients. Symptoms include poor growth and blooming, dark green leaves, yellow leaves, misshapen leaves, and leaves that fall off. 

To determine the pH level of your soil, you can purchase a testing kit. If the soil is too acidic, agricultural lime, Epsom salts, and other agricultural agents can be added. Conversely, if the soil is too alkaline, a sulfur amendment can be mixed in with the soil to bring the pH down. 

Mineral Build Up

Plumeria is sensitive to poor-quality tap water containing high levels of minerals and water treatment chemicals. As such tap water can lead to irregular soil pH levels as salts and other mineral compounds build up in the potting soil. 

This type of yellowing often begins as patches of yellow on the leaf edges and turns crispy brown. 

To fix this, move away from using tap water and instead try rainwater or filtered water. Then flush your potting soil to remove the mineral buildup, or simply change the potting compost. 

Iron Deficiency 

Plumeria requires iron for the production of chlorophyll, which gives the plants their green color. Iron is also vital for photosynthesis as it helps move oxygen through the plant. Plumeria obtains iron from the soil itself or from decomposing matter, such as compost. 

Iron deficiency manifests itself in young or new leaves that are yellow in color with distinct green veins. An iron deficiency can be caused by a high (alkaline) soil pH, overwatering, or an imbalance of other nutrients in the soil that may prevent the uptake of iron. 

If you see these green veining symptoms in your leaves and feel that your plumeria may be suffering from an iron deficiency, you should perform a soil test. The soil pH will affect how much iron the plumeria can absorb. Plumeria with an alkaline pH should be treated with a fertilizer rich in iron, which you can mix into the soil.

Pests

There are a few common garden pests that enjoy plumeria a little too much. Scale, thrips, and whitely are all capable of turning your plant’s leaves yellow. 

Scale

Scale are small oval-shaped insects that often appear as bumps or scales on the surface of leaves. A common symptom of scale damage on leaves is yellowing or discoloration.

This occurs as a result of the tiny insects’ feeding activity, which leads to weak and wilted leaves. In severe cases, the entire leaf turns yellow and drops from the plant.

Kill the scale with rubbing alcohol, applied to a cloth or cotton wool, and then rub the leaves. The alcohol will kill the insects immediately.  

Frangipani Caterpillar

Frangipani caterpillars are the larvae of the frangipani moth and they feed voraciously on plumeria leaves, often causing complete defoliation of the plant. A common symptom of frangipani caterpillar damage on plumeria leaves is skeletonization, as they chew the leaf down to its veins. 

Remove Frangipani caterpillars by picking them off and either disposing of them or if you are more macabre many gardeners destroy them by squashing them between fingers and thumbs.

Thrips

Thrips are tiny, slender insects that can cause significant damage to plumeria leaves. They feed by piercing the surface of the leaves and sucking out the sap, which can lead to a variety of problems.

One of the most common symptoms of thrip damage on plumeria leaves is silvering or bronzing of the foliage. This occurs as a result of the insects’ feeding activity, which causes small patches of dead tissue to form under the leaf surface

Whitefly

Whiteflies feed on plumeria by piercing the leaf surface and extracting sap, which can lead to a variety of problems, including yellowing. This occurs as a result of the insects’ feeding activity, which can cause leaves to become weak and wilted. 

Remove the white with a soapy water solution, simply spray the leaves or wash them with a soft sponge. 

FAQ Plumeria Leaves Turning Yellow

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.