Why are my bonsai leaves turning yellow?

You have been reading all about bonsai care, you constantly check your tree so that it does not lack anything, and you pamper it as much as you can… even so, your bonsai leaves turn yellow. Why does this happen? Do you want to get rid of yellow leaves?

In this blog we are going to show you different situations that can cause yellowing leaves on your bonsai, and we will help you find solutions.

Yellow leaves on bonsai

The characteristic green colour of plants is because of chlorophyll, a nutrient that the plant generates to feed itself. When this nutrient is lacking, the green colour becomes paler, even yellow. The lack of chlorophyll is called chlorosis.

What if there is no chlorophyll? Photosynthesis does not take place and, as a consequence, the affected leaf dries out and falls off. Another thing to keep in mind is that a leaf affected by chlorosis is more prone to pests.

Main causes of yellow leaves on bonsai

Wrong irrigation technique

One of the most frequent causes is a wrong watering technique. Wrong watering, besides fatal consequences for bonsai, can also cause chlorosis. We may notice that, if we have been watering excessively, a large part of the leaves of your bonsai are of an intense yellow colour.

Only some of the leaves turned yellow

When bonsai, and plants in general, cannot meet their water needs, they get rid of some of their leaves in order to ration water and save energy. In that case, your bonsai will only have some yellow leaves, not all of them. It is a sign that our bonsai is telling us that it is not getting enough water. If you want to learn more about proper watering technique, you cannot miss these two videos, where we explain how to irrigate your bonsai depending on its location, indoors or outdoors.

Inappropriate location

To photosynthesise correctly, it is essential that our bonsai receive a fair amount of sunlight. We must remember that a bonsai is still a tree. If we keep it indoors, we must take account of the amount of light your bonsai species requires. If our bonsai is located where it does not receive enough sunlight, we can notice it in several ways.

For example, one way to notice is if new leaves are bigger but lesser in quantity. Another way to notice is if we see that the branches of the bonsai go in a specific direction, searching for sunlight. The little tree will lose its original shape. These situations can cause chlorosis too. You will notice those leaves that receive less light slowly get more pale and yellow.

Lack of Nitrogen

Phosphorus, Potassium and Nitrogen are the main nutrients that bonsai and plants need in order to live well. Due to its importance, the lack of these nutrients can lead to some negative consequences for our bonsai.

On the one hand, lack of Phosphorus and Potassium can affect root development, flowering and fruiting. On the other hand, Nitrogen is responsible for enhancing the green colour of the leaves, as well as contributing to growth. For these cases we can apply a fertiliser rich in nutrients, such as Nutribonsai, to solve this imbalance and provide enough reserves to the bonsai.

Iron deficiency

The lack of iron or its malabsorption can also go hand in hand with chlorosis, in this case, iron chlorosis.

In this situation, we recommend that you check if the substrate in which the bonsai is located is adequate and apply Ferrobonsai (iron chelate) to give the bonsai this necessary micronutrient.

We hope we have helped you with the care of your bonsai and encouraged you to grow your collection.

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