The Juniper bonsai is a popular choice for beginners because it’s easy to care for. The tree is resistant to pests, illness, and drought. However, if not properly cared for, the leaves can turn yellow and die or fall off of the tree.

In this post, we will try to understand why your juniper bonsai is turning yellow and what you can do to prevent this from happening.

Why is My Juniper Bonsai Turning Yellow?

A juniper bonsai tree can turn yellow due to many reasons like lack of sunlight, improper watering schedule, lack of nutrients, etc. once you find out the reason you can take the necessary steps to prevent the yellowing of the plant.

Here are a few common reasons why a juniper bonsai is turning yellow:

Sunlight:

Juniper trees need a lot of light to survive and thrive. Many species prefer 5-6 hours of direct sunlight per day. The green color of the leaves is produced by the presence of chlorophyll, a vital compound in the photosynthetic process.

Chlorophyll is produced by the plant when there is enough sunlight. If sunlight is not available, the plant produces less chlorophyll, and this causes yellowing of the leaves.

If your juniper bonsai is indoors and doesn’t get direct sunlight, it will turn yellow due to a lack of chlorophyll.

Find out how much sun the tree is usually getting. Put the tree outside in an area with partial shade where it can get some sun each day.

juniper bonsai turning yellow — image source Flickr

Overwatering:

Another reason for discoloration is overwatering. Junipers naturally thrive in hot, dry environments, so they actually do better when they are allowed to dry out between watering sessions.

If there is too much water on the roots, it can damage them, and this will cause the needles to turn yellow or brown. It may also cause root rot, which can kill your tree.

Underwatering:

Underwatering can be a cause of the yellowing of juniper leaves. If you’re not watering your tree often enough, the needles will start to turn yellow as they dry out.

When this happens, it’s important to stick to a proper watering schedule before any permanent damage is done. Find out how much water it usually gets.

Soil and Manure:

It’s possible that your soil or manure could contain too much/little or no nutrients for your tree, which would cause the leaves to turn yellow. To fix this you should mix a new batch of soil using Akadama, Pumice, Lava rock, and Humus, making sure that all ingredients are sterilized before use.

The most likely cause of yellowing foliage is iron deficiency. Junipers require a small amount of iron to be able to process nutrients and produce chlorophyll. If they don’t have enough iron, they can’t produce chlorophyll – the green pigment that gives plants their color.

Many bonsais are grown in poor soil mixes and will benefit from regular applications of chelated iron to give them a boost. You might need to use a nutrient-rich potting mix for your juniper if you find this is an ongoing problem.

Pruning:

Junipers respond very well to pruning but too much pruning can cause stress problems that result in yellowing leaves falling off.

If you have recently pruned your tree back then this could also cause the needles to turn yellow and drop off. This is normal as new growth will emerge within a few weeks of pruning.

Pest and Diseases:

Junipers are prone to spider mites and if left untreated they can cause significant damage that includes browning of the leaves, discoloration, and dieback of branches.

Diseases can also cause yellowing in Juniper bonsai trees.

Repotting:

If your bonsai is turning yellow, it can also be probably because the tree has just been repotted recently. Newly repotted trees are stressed, and they will shed some of their leaves to reduce transpiration.

How to Prevent Yellowing of Juniper Bonsai:

There are many things you can do to prevent the yellowing of a juniper tree but the first step to saving your juniper is to properly identify the problem. Junipers in good health are not yellow. Here are some suggestions:

Junipers that are turning yellow due to lack of sunlight will turn a golden yellow and the needles will be brittle. If you notice this, move your tree to an area that receives more direct sunlight. Sunlight helps the plant produce food to survive and thrive, so it’s important that it gets enough sunlight, but not too much.
If your bonsai is turning yellow due to overwatering, the needles will be soft and limp. This means you are watering too frequently or providing too much water at once. To fix this problem, let your bonsai dry out some before you water it again. You should also consider adding more drainage holes or using a pot with better drainage.
If the soil is extremely dry and the needles are still turning yellow, then you’re probably underwatering your bonsai. If your soil is dry, water it thoroughly and allow the water to drain through the pot. You may need to do this multiple times if the weather is too hot.
Increase watering frequency or amount slightly until the color of the needles returns to green or blue-green (the normal color of juniper needles). To avoid this from happening in the future, be sure to keep an eye on your soil. When it gets dry, water it!
Junipers like humidity, especially if they are kept indoors. Try using a humidifier or placing a tray of pebbles with water under your plant to keep it moist. You can also mist the tree with water occasionally.
Prune only when necessary and use sharp tools so you don’t damage the trunk or branches when cutting back. If you have a pest or disease issue your needles will turn yellow and maybe fall off depending on the severity of the infestation. Make sure to check off other causes before you assume it’s a disease or pest issue.
Your bonsai can become root bound after some time and may need repotting. Check if the roots have started growing out of the pot or if they have become dense and matted inside the pot. If yes, you should repot your tree in a bigger container immediately. Repotting will promote growth in your bonsai and bring back its health.

Junipers are a classic bonsai for both beginners and professionals. The trees are hardy and adaptable, so they are forgiving of beginner mistakes. With proper care, junipers can live for hundreds of years. Read about juniper bonsai care here in this post.