Why is my Bougainvillea Losing Leaves?

If you see your Bougainvillea losing leaves, there’s a valid reason for you to be concerned. It’s not normal for your bonsai tree to do so, especially since most species are evergreen. However, there are times when this may happen, and you’ll need to either accept it or take measures to fix it.

In this article, we’ll cover what you should do with your Bougainvillea losing leaves.

Bougainvillea losing leaves

Do Bougainvilleas Lose Their Leaves?

Hardiness zones 9 to 11 are the most ideal regions for Bougainvillea bonsais to grow. They simulate the conditions of the South American countries where they thrive, and you won’t need to put in too much work to keep them alive. However, you may still find Bougainvilleas losing leaves under the best living situations for various regions.

Remember, Bougainvilleas are mostly evergreen, especially in warm, temperature regions. From the moment they feel too cold, they become semi-deciduous. That means that the leaves will change color and fall down when the tree goes dormant, resting until the spring arrives.

Why is Your Bougainvillea Losing Leaves?

There could be many reasons for your Bougainvillea losing leaves. Some of them are natural, while others are issues you need to resolve before they become worse. We’ll look at the main causes first before we provide the solutions.

Cold Temperatures

Brazil, Peru, and Argentina have warm climates for most of the year, which is what the Bougainvillea has become used to over the centuries. They remain evergreen all the time, showcasing leaves and flowers even when winter arrives. The same can’t be said for bonsais in colder areas.

Any regions outside hardiness zones 9 to 11 have the chance of being too cold for the Bougainvillea. It becomes deciduous, losing its leaves when it goes dormant. If you have a lot of rain in the winter, the lack of direct sunlight can also cause problems, which we’ll cover in a moment.

Too Much Water

Bougainvilleas are used to drought-like conditions with very little rainfall. Their roots are adapted for dry soil, and they don’t like lying in water for too long. When there is too much moisture, it causes them to stress, which is never good for any bonsai.

This stress makes Bougainvilleas lose their leaves, giving you a sign that something is wrong. Related issues are insufficient drainage, watering too often, water trays preventing the liquid from escaping, and heavy rainfall for a few days. The moist soil can also cause problems like root rot.

Insufficient Sunlight

For the best growing condition to prevent Bougainvillea from losing leaves is full sunlight for a couple of hours. Too much shade means that it can’t create enough energy for developing leaves and flowers. You need to provide it with at least six hours every day so the leaves can remain healthy.

However, you don’t want to simply move it into sunlight immediately, as that can also cause the leaves to fall. Give it time to become used to the light before you leave it in its permanent position. In winter, it may lose its leaves if there isn’t enough light during the rainy parts of the season, becoming deciduous.


If you’ve recently purchased a Bougainvillea bonsai online or from your local store, don’t stress if you see it losing its leaves. The tree becomes used to sunlight, humidity, airflow, and temperatures, and any sudden changes will cause it to react until it adapts to the new area.

The one thing you should stay away from after moving the tree is fertilizer. Since it’s in a state of stress, you need to give it time to become used to your home. Trying to force it to grow with food will just make matters worse.

Insufficient Nutrients

If you’ve had your bonsai for several years and it’s the first time the leaves are falling, it could be due to a lack of nutrients. The soil loses macro- and micronutrients over time, which is why it’s better to replant them in new soil after a few years.

Of course, you can help it along with fertilizer that has nitrogen, phosphorous, and potassium (NPK). These help develop strong leaves, branches, roots, and flowers, especially over the growing season. We always recommend a balanced approach, but it depends on which part of your Bougainvillea bonsai you want to develop more.

Diseases and Pests

Finally, another reason you Bougainvillea is losing leaves could be from pests and diseases. The number one culprit is root rot, which is linked to overwatering. You can check the soil and roots to see if any mold has formed, which will reveal that there’s too much water not draining properly.

There are also other fungal conditions that may be the culprit, such as leaf spots. Some pests feed off the leaves and stem, which will result in them dying and falling off. Daily inspections of your bonsai tree can quickly help you identify the problem.

Bougainvillea losing leaves

What Do You Do When Bougainvillea Leaves Fall Off?

While many of these conditions can be devastating, there are some actions you can take to solve the issue. We have a few listed here that will help your Bougainvillea bonsai recover from losing its leaves.

When It’s Too Cold

If temperatures drop below 41° F, it’s best to bring your Bougainvillea indoors to prevent it from losing leaves. The shock of the cold will make it stress and go into dormancy, and sometimes the frost may even kill it. You’ll want to provide an indoor environment that’s warmer, but don’t worry if you still see some of the foliage fall off due to winter.

Less Watering

To prevent overwatering, you need to slow down how often you water your Bougainvillea bonsai. You can press your finger into the top 4 inches of the soil to see when it’s dry enough to give it a lovely bath again. Even if it feels dry, you can go a few more days without water.

We also recommend you improve the drainage with some rocks at the bottom to let the water flow out quicker. Don’t let a tray catch any of the liquid, as you need the soil to dry out as quickly as possible after watering. You should see an improvement in your leaves after about 2 weeks.

More Sunlight

If you’ve detected that there’s insufficient sunlight, move it to an area where it can at least get six hours of light in the morning and evening. You don’t want the leaves cooking in the afternoon heat. There needs to be some shade at about noon to prevent leaf burn.

Also, the Bougainvillea enjoys shorter days. So while you provide enough sunlight, you’ll need to cover it with a shade cloth once it’s had enough light. If you have it indoors, make sure you place it by a window so it can still get the sunlight directly.

When Repotting

When you transplant the Bougainvillea to a new pot, you should expect some leaves to fall. However, you can lower the risk by providing adequate care as mentioned above. Don’t overwater it, and ensure that there’s enough light, especially in the first few weeks.

We also recommend you don’t prune the roots too much. You only need to trim enough for it to fit in the pot without filling it completely. If you prune too much away, it may spend more time regaining the roots while dropping the leaves.


The growing season is an essential time for feeding your Bougainvillea bonsai. In spring, you’ll want to focus on high nitrogen content so the leaves and form completely. You can have it as the same ratio as phosphorous and potassium, or slightly higher. If your tree is deciduous and dormant in winter, you should stop feeding it completely.

In summer, your bonsai should move its focus to flower, so you can reduce the nitrogen levels and increase phosphorous and potassium. You may also want to add some calcium and magnesium, but these micronutrients are usually included in good Bougainvillea fertilizers. Also, make sure the soil remains acidic for good nutrient absorption.

Killing the Pests and Diseases

One of the top reasons for Bougainvilleas losing leaves is a pest or disease. They can be hard to identify, and it make take you a while before you realize this is the problem. If you see any pests infesting the leaves, like mites and aphids, we recommend a good organic pesticide.

If root rot or leaf spot are the issues, you’ll need to look at fungal remedies. Some fungi are incredibly challenging to combat, while there are diseases with no cures. You may need to remove some of the more damaged leaves to save the rest of the tree.

Bougainvillea losing leaves

Checking the Symptoms

While most of the symptoms above are easy to tell, there are many that aren’t. We’re going to show you what to look out for so you can tell the cause directly.

How Do I Know If My Bougainvillea Needs Water?

The fastest way to tell if your Bougainvillea needs water is to test the soil with your finger. It should be relatively moist in spring and summer, while you need it to dry out before you apply any more water. If your tree goes dormant in winter, you should let it become completely dry for a few days.

How Do I Know If My Bougainvillea Is Dying?

There are a few tell-tale signs that you Bougainvillea may be dead. For instance, the branches, bracts, and leaves may shrivel up, while it has a deadly look about it. You can snap one of the stems easily, and if there’s a crisp sound with no resistance, then there’s no life in it anymore.

Another way you can tell is by scratching the bark with your nail until you get to the cambium layer. You should see a hint of green if it still has some life in it. If it’s dry and brown, then your bonsai tree is dying.

How Do I Know If My Bougainvillea Has Root Rot?

When you provide too much water to a Bougainvillea, the leaves will wilt and fall. You can check this condition by placing your hands or tools in the soil and seeing if there’s any mold or a foul odor.

The best measure to take is to replace the soil completely. If root rot develops too far, your bonsai tree will die completely. You need to let the new soil remain dry so the roots have a chance to recover. Then, you can bathe it in water and leave it for about two weeks to dry again.

How Do I Know If My Bougainvillea Has Enough Light?

The reason a leaf looks green is that the chlorophyll in the cells doesn’t absorb the green color in light’s wavelengths. When your bonsai tree receives enough sunlight, the leaves will have a healthy, rich color that’s stunning to behold. Even the modified leaves, the bracts, will look outstanding, so you can tell if there’s insufficient light by how healthy and colorful the leaves are.

Bougainvillea losing leaves

Final Thoughts

You don’t need to stress too much when Bougainvilleas lose their leaves. As you can see, there are numerous ways you can assist your bonsai tree in proper foliage development. We hope our guide has helped you along the way in ensuring that it doesn’t lose too many leaves.

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Shaun has two passions in life that combine into an extravagant show on Bonsai Alchemist. The one is for writing and the second bonsais. He’s been writing fantasy and horror novels since 2000, while also creating online content since 2015. He’s involved with writing for films and games. Finally, he’s also the owner of a book publishing company.

He received his first bonsai as a gift in 2009 and has been growing several species in his quiet home in South Africa. He prefers propagating new life instead of buying bonsais at the store. His son and daughter share his love for nature, while his wife stares on at her introverted hermit husband.


Shaun M Jooste


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