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Brown Spots on Plumeria/Frangipani (Treatment, Causes And Prevention)

Indoor potted plumeria leaves have brown spots

Also known as Frangipani, Plumeria is one of the best-smelling plants that can add a perfect combination of aroma and landscape into your indoor garden.

With their different varieties of flower colors, these shrubs will surely attract the eyes of anyone who visits your home.

As much as it can attract attention, your Plumeria can also attract different kinds of nuisances that can damage its beauty.

One of the common problems that your Plumeria might experience is the sudden appearance of brown spots in your plant’s leaves.

If your Plumeria has brown spots, make sure to first isolate it from other houseplants while looking for the possible cause, regulate water intake, provide adequate and indirect sunlight, apply proper treatment for pathogen infestation, and supply necessary nutrients on its soil.

Though this might be bothering for a newbie gardener, still with proper understanding and correct treatment, your Plumeria will most likely live. 

If your plant is experiencing the same browning scenario on its leaves, this article is highly recommended for you. 

How to Identify Brown Spots on Plumeria

Commonly, the brown spots in your Plumeria are caused by Plumeria Rust. A disease where Coleosporium Plumeriae, a fungus, sticks to your plant’s leaves and then produces spores that affect its leaves’ foliage.

The brown spots on plumeria can be first identified with some yellow specks on the top part of the leaves.

These specks will later turn into brown or grey until the leaves totally wither.

If you would also check underneath your plant’s leaves, you will see countless yellow-orange powdery lesions.

These lesions are capable of producing spores, causing your Plumeria to get ill.

Brown spots are common to the leaves of Plumeria and it doesn’t affect the stems and the flowers of your plant.

Though it’s unusual to have those spots on your plant’s flowers, there are still times that the sides of those flowers might start to decolorate until they wilt. 

Why Has My Plumeria Got Brown Spots?

Though Plumeria Rust Fungus is the main culprit of those brown spots in your plant, we still can’t ignore other possible causes of that scenario. 

Here are some of the factors that can help you determine why your Plumeria has brown spots.

Fungal Diseases

Fungal infestation commonly occurs when the soil of your plant builds up too much moisture.

This usually happens a lot during cold seasons, especially when you overwater your plant or fail to provide a good drainage system to its pot.

Many possible culprits cause fungal disease in your Plumeria. Here are the possible fungal diseases and treatment.

Plumeria Rust

Causes: It is caused by Coleosporium Plumeriae, a fungus that usually travels through air and sticks on the leaves of your Plumeria. From there, it germinates spores that infect the cells inside those leaves.

Symptoms: The symptoms start with visible yellow spots on the top of your plant’s leaves that will eventually turn brown if not treated immediately. You can also see some drying, curling, and withering of other leaves.

Treatment:

  • If you find out that your Plumeria is suffering from rust, immediately remove all infected leaves to avoid further damage to other parts of your plant. Be careful not to shake the leaves while cutting to prevent dropping spores.
  • Dispose of all the infected parts straight to your garbage bin, then wash your hands thoroughly before touching the remaining healthy leaves.
  • Check on your pot drainage and remove possible excess water in the dish.
  • Be mindful in watering your Plumeria since they don’t love soaking in water. Allow a couple of days of draining before watering again.
  • If possible, isolate your Plumeria from the rest of your houseplants to avoid the transfer of infestation.
  • While relocating your plant, make sure that it receives adequate light, preferably 5-6 hours of full sunlight.
  • Spray fungicide on the leaves and soil of your Plumeria plant to avoid recurring infestations.

Powdery Mildew

Causes: When fungus carrying mildew starts the invasion, they usually leech on your plant’s nutrients that cause your Plumeria’s leaves to wither.

Unlike other fungal infestations, Powdery Mildew can operate even in a hot environment as long as there is enough moisture.

Symptoms: The symptom of the disease is an obvious appearance of white blisters on the top of your plant’s leaves.

If not immediately prevented, this may also cause some yellow or brown spots on its leaves.

Treatment

  • Immediately separate all infected Plumerias from the rest of your plants.
  • If the infestation is not yet severe, you can use some organic remedies. Spray a mixture of 1 teaspoon baking soda in a liter of water.
  • You can also use neem oil to wash off the powdery substance.
  • In case the infestation is severe, don’t hesitate to get rid of your plant as soon as possible to avoid further disaster in your indoor garden.

Black Tip Fungus

Causes: This fungal infestation occurs when ants create a hole on the tip of your plant and store inside all the sugary excretion of Mealybugs that they have collected.

Sooner it will become a nesting ground for fungi, thus turning the tip of your Plumeria crusty and dark.

Symptoms: The symptoms are dark-colored tips of your Plumeria. In the worst cases, this infection will spread and also destroy the stems and leaves of your plant.

Aside from those signs, your Plumeria will also be deprived of nutrients resulting in some blooming issues.

Treatment

  • Apply first a broad spectrum fungicide to eliminate the main culprits of this disease, the insects.
  • Save the tip of your Plumeria by spraying seaweed extract liquid fertilizer. You can also damp a cotton soaked in hydrogen peroxide to minimize the darkening of the tip.
  • If the tip continues to darken, you may now want to prune it to prevent further damage. Eventually, it will grow back during hot seasons.
  • Place your plant in a warm location, especially during the winter.

Sooty Mold

Causes: These fungi grow from the honeydews that some insects left after sapping your plant’s fluids.

Though this illness doesn’t create direct damage to your plant, still the coating that it produces might block the sunlight from your Plumeria’s leaves.

Your plant will not be able to perform photosynthesis, which may cause discoloration and growth deterioration.

Symptoms: You will most likely see some black-powdered coating in your plant’s leaves and twigs.

Usually, spring rains wash off this powder revealing the leaves with some brown blemishes.

Treatment

  • You should try to eliminate first the insects residing on your plant, the same with Black Tip Fungus. In this scenario, the main culprits are ants, mealybugs, and other sap-sucking insects. 
  • Apply a broad-spectrum fungicide to tend off those intruders.
  • Pruning is also an effective strategy. By removing the infected areas, you are lessening the chance of infection, thus allowing your plant roots to prioritize supporting the remaining healthy leaves.

Too Much Sunlight

Although Plumeria often thrives in sunny environments, you can’t ignore that too much sunlight may lead to scorching your plant’s leaves. 

The typical victims of scorching are usually the cuttings that you have propagated or those newly planted Plumeria.

The typical symptom that you can see aside from the spots is burned marks on your Plumeria’s leaves or stems.

How to Treat:

  1. You may want to start relocating your plant as soon as possible to control the lighting system. Preferably. A south-facing window where it can receive five to six hours of sunlight.
  1. If you can’t relocate your Plumeria, consider putting a shade on your windows to control sunlight’s entry.
  1. Water your plant to recuperate the water it loses due to excessive heat.
  1. Don’t forget to drain your Plumeria thoroughly to avoid pathogenic attacks.

Watering problems

Too much watering to your plant can cause rotting on its roots, thus making the roots soggy and incapable of transporting water to sustain your plant’s physiological needs.

The next thing you’ll know is there will be a shortage in Chlorophyll, which therefore comprises the process of photosynthesis.

That scenario will result in discoloration of your Plumeria’s leaves, starting from light yellow marks until it turns into dark-brown spots. 

How to Treat:

  1. Newly planted Plumeria should be watered once every two weeks. As much as possible, try not to overwater your plant since it’s in the process of rooting. Usually, the rooting process will take 5-6 weeks, so watering is less likely needed during that time.
  1. If your plant shows some sign of growth in the form of tips and developing leaves, you can adjust your watering to once weekly.
  1. Once the leaves are fully developed, you can now water your plant on a much more regular basis. Ideally, watering could be within 3 days of interval. 
  1. During its dormant season, avoid watering the plant except if you’re living in a region with a dry winter.
  1. Remember that your plant needs a high volume of water when exposed to a high volume of sunlight.
  1. Importantly, maintain a functioning draining system to avoid waterlogging. You can add holes underneath your pot or elevate your plant if needed to assist the draining process.

Insect Infestation

Due to your Plumeria’s natural beauty and healthy sap, it’s not surprising that it attracts different kinds of sap-sucking insects.

Now, if sap-sucking insects are lurking on your plant, then most probably, there will be plenty of honeydews that can also attract ants.

With that unfortunate scenario, you might be thinking of giving up your plant. 

Hold on! This might be miserable, but you could still restore your Plumeria if you know how to deal with those unwanted visitors in your garden. 

But before the termination happens, you need to identify first the culprit whom you’re dealing with.

To help you with that, I will discuss appearances, damage type, and symptoms of the insects.

Mealybugs

Appearance: These are wax-coated insects that usually appear as a cottony substance on the leaves of your Plumeria.

Damage Type: Mealybugs suck sap from the phloem of your plant and excreting honeydew, which supports fungi’ growth.

Symptoms: Due to fungi growth, the usual symptoms that you will encounter are from those fungi-related diseases.

It could be some leaf discoloration, tip darkening, and the appearance of brown spots.

Treatment

  • Gently rub the leaves with cotton soaked in alcohol.
  • Naturally, Mealybugs can be lessened by their natural predators like beetles and wasps. But you need to eliminate all the ants in your plant since they’re protecting them from those predators.
  • If the infestation is severe, try using insecticidal soaps to save your Plumeria. In case it’s still not working, dispose of your plant to prevent the relocation of mealybugs.

Spider Mite

Appearance: It is a microscopic insect with many kinds that varies depending on the number of spots. They are usually yellow in color and travel through wind or via birds.

Damage Type: These mites suck on your Plumeria’s juices that cause discoloration and brown spotting on your plant’s leaves.

Symptoms: Usually, you will see some deformed leaves with brown spots accompanied by leaf dropping. 

Treatment

  • Isolate your plant immediately.
  • Spray horticultural oil on the leaves of your plant. Make sure that your Plumeria is wall-watered and not exposed to excessive sunlight to avoid stress.
  • You can also use insecticidal soaps if needed. 

Leafhopper

Appearance: These are light-green colored insects with two bands and transparent orange wings at the back. 

Damage Type: Known for their severe infestation, these insects are always associated with damaged leaves.

They usually hang out at the margins of your leaves, sucking all the plant juices from the phloem.

They also inject phytotoxic substances into your plant as they feed.

Treatment

  • Consider trimming off all infected leaves since most of the leafhopper’s eggs lay there. 
  • Spray a mixture of 3 drops of dish soap into a cup of alcohol. 
  • If possible, allow its natural predators such as wasps and spiders to thrive in your garden.

Ants

Appearance: These are the usual ants that you can see at home.

Damage Type: Initially, these ants don’t bring any damage to your plant at all. But they contribute to the process of collecting honeydews and storing it in the holes of your Plumeria’s tips, thus providing a favorable environment for fungi to grow.

Since ants love honeydews, they also tend to protect all sap-sucking insects in your plant.

Symptoms: Ants are very visible, so you will know right away if your Plumeria hosts these culprits. Apart from that, you will also see some holes in the tips of your plant.

Treatment

  • Initially, if you successfully removed all the honeydew-producing insects in your garden, then most most likely ants will leave your plant.
  • You can also sprinkle cinnamon around your plant to shove ants away.

Fertilizer Problems

Overusing your fertilizer might cause certain problems as well in your Plumeria. 

Your plant enjoys slightly acidic soil, so adding some acidic contents such as salt and coffee grounds will help.

But to give you further details on how you can help your plant regarding its nutrients, check the table below.

NutrientsProblemsSymptomsCorrections
PhosphorusA low level of soil pH affects the production of phosphorus.Leaves turned darker with dark reddish spots visible to its leaves.Add phosphate or Phosphorus-based fertilizers.
NitrogenNitrogen is soluble in water that’s why it’s having a hard time reaching the leaves.
Discoloration and appearance of dark spots

Add ammonium nitrate to the soil. 
PotassiumPotassium is abundant in soil and water, so deficiency problems are minimal. Commonly, excessive Potassium is more likely to occur.Leaves might look scorched or wilted since some of the nutrients are absent in the leaves of your plant.Add organic fertilizer to your soil. You can also use crushed eggshells to balance soil nutrients.
(Source: University of Arizona)

How to Prevent Brown Spots on Plumeria?

Preventing those brown spots from appearing on your Plumeria is easier than dealing with it when it arrives.

If you could avoid those causes above, you can have a good chance of having a thriving and blooming Plumeria in your garden.

  1. Check the plant thoroughly for possible disease or infestation before purchasing and bringing it home.
  1. Though your Plumeria loves sunshine, you still need to make sure that it will not stay longer than 6 hours. Use blinds and covers to limit the entry of light.
  1. The proper watering system according to your plant’s season is necessary for its growth. You may refer to the watering solutions above.
  1. Check the drain holes of your pot for possible clogging to avoid fungal infestation.
  1. In supplying nutrients, consider using fertilizers high in phosphorus.
  1. Weekly apply insecticidal soap to remove or prevent the invasion of insects.
  1. If you wish to propagate your Plumeria, use well-drained soils such as cactus mix or a combination of potting soil and perlite
  1. Lastly, maintain cleanliness in your area by adequately disposing of damaged parts and rotted leaves. Also, don’t forget to sanitize all your equipment.

Final Words

If properly maintained and taken care of, your Plumeria will eventually flourish and will add a picturesque scene in your garden. 

Though there are unfortunate situations where your plant will experience stress and invasion, still with enough sunlight, adequate water, and proper nutrients, your Plumeria will indeed survive and thrive.

If your Plumeria is having brown spots, refer to the list of causes above and identify the correct ways on how to deal with it. Bear in mind that your plant requires proper attention and sufficient time to grow and produce beautiful flowers.