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Why Is My Bonsai Turning Yellow? (8+ Possible Reasons and Ways to Prevent It!)

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Is there anything worse for a gardener than seeing their plants turn pale and yellow? I don’t think so. So, what to do if the bonsai in your garden is turning yellow? This article answers all your questions regarding why is my bonsai turning yellow. How to identify its cause? What is the treatment? And how to prevent it?

A bonsai is a form of a miniature tree that is used to obtain source material. Within a confined space, they are a replication of nature. All a bonsai tree needs is a pot of soil and a lot of love.

There can be many answers to the question why is my bonsai turning yellow? It may be due to its annual cycle of deciduousness, it might be due to any plant infection or disease or it can be due to any other condition prevailing.

The first step to beginning the treatment is the identification of the problem. Let’s have a look at all the possible reasons for this problem along with their solution to help a gardener!

Why Is My Bonsai Turning Yellow 1
Leaves keep turning yellow and falling off. – via Reddit

Why Is My Bonsai Turning Yellow?

The identification of the cause of yellowness on a bonsai tree can be challenging. This is because yellowness can be a symptom of various reasons. Here you can get a few common reasons why is my bonsai turning yellow?

1. Annual Cycle

Like all other trees, a bonsai tree also sheds its leaves in autumn. It is very normal for tree leaves to turn yellow before being shed. Check the time of the year to find out if the yellowing of bonsai is due to deciduousness or any other reason.

So if you see a bonsai tree turning yellow in autumn, probably there is no need to worry as it is a part of their normal annual cycle.


If there are just a few leaves turning yellow and being shed, it is considered natural and normal. If many leaves including new shoots are changing their color, check for some other problems.

2. Underwatering

Out of various reasons, a common reason for bonsai leaves to turn yellow is the problem of underwatering.

The roots of a bonsai tree need to be soaked in water but don’t need the water to be stagnant over the soil. If the water requirements of the tree are not met properly, it can be the reason for its yellowing.


Add water to the soil of your bonsai tree in stages. Add some water and wait for the soil to absorb it. Keep on watering until the topmost layer feels soaked.

3. Overwatering

A bonsai tree needs to be watered according to its needs depending upon the environment and the time of the year. It might require no watering per day to multiple waterings a day depending upon internal and external factors.

If more than required water is given for a longer period, it may cause your bonsai tree leaves to change their color.


Check your bonsai tree’s requirements for water intake to prevent overwatering or underwatering. Keep checking the soil for the presence of moisture.

4. Sunlight

A major reason for a bonsai tree to turn yellow is the lack of sunlight. Like many other plants, a bonsai tree also requires a large amount of sunlight to survive. Plants must produce chlorophyll for their survival. A lack of chlorophyll turns leaves yellow as not enough green pigment is being produced.


A moderate amount of sunlight should be provided to the bonsai tree whether it is direct sunlight or indirect. It needs around 5 hours of sunlight per day to avoid causing the yellowing of its leaves.

Why Is My Bonsai Turning Yellow 2
Please Help, Yellowing Juniper Bonsai – via Reddit

5. Plant Stress

Another common cause for the leaves of a bonsai tree to change their color and turn yellow is plant stress. Being over-trimmed can cause stress in a bonsai tree.


Trimming should be done when the plant is in the dormant stage to avoid causing plant stress. It is not advised when the tree is newly planted or right after an environmental change.

6. Wiring

If you are using a wire to support your bonsai tree to grow, there is a chance that it may break into the bark. It might leave the tree vulnerable to infections and diseases.


Make sure the wire placed for growth is removed in the same season in which it was placed.

7. Environment

Bonsai trees are cold-sensitive as they need direct sunlight for their growth. They do not like extreme dry conditions, as they want a lot of sunlight. The ideal environment to keep a bonsai tree is 70% humidity and direct sunlight.


Ensure the right temperature levels for the growth of bonsai trees. The biggest threat to such plants is a cold environment. Proper measures should be taken to provide a warm temperature and direct sunlight.

8. Minerals

Fertilizing the soil is an important step to keeping your bonsai tree healthy and happy. Maintaining the required level of minerals is necessary as minerals more than required can also prove to be harmful to the plant. 


Check and balance of minerals can be maintained by using a soil testing kit. Fertilizers specialized for bonsai trees can be the best possible solution to this imbalancement. They need to be fertilized every 7-10 days in the growing season for normal growth.

9. Repotting

Transferring a bonsai tree from one pot to another can cause the yellowing of leaves. It may be due to plant stress a tree can face due to changes in the environment.


Make sure to use new soil and a pot that is large enough for roots to grow. Also, required temperature and environmental conditions should be maintained before repotting.

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A bonsai tree is not so difficult to keep, as it only requires the right type of environment and lots of love to nourish and grow.

This article has all the answers to your question why is my bonsai turning yellow? All you need to do is look for the problem that is causing yellowness and start working on its treatment.