Growing, cultivating, and maintaining a bonsai tree takes some particular care, and they can be notoriously temperamental plants if you are not careful. You always need to have your eyes open to spot any signs that something may be going wrong, so what does it mean if you see your bonsai tree turning yellow?
When it comes to all things bonsai, knowing as much as you can is key to keeping your plant growing in the right way. In this article, you will find out everything you need to know about why your tree might turn yellow and what you should be doing about it.
Is It Normal for Bonsai to Turn Yellow?
It is a very common occurrence for a bonsai tree to turn yellow and can be perfectly healthy for some species. Don’t forget that bonsai trees are fundamentally the same as regular trees, just specially curated to grow in a miniature form and a particular shape. It is perfectly normal to see yellow leaves on many different kinds of trees, including bonsais.
The most important thing is to understand why this color change is happening and whether or not it is healthy for your bonsai in particular. There are many different reasons why a bonsai tree might start to turn yellow, and not all of them are cause for alarm or even signs that anything needs to change.
Of course, any changes to your tree will be alarming, but it rarely means that your tree is in any significant danger. Even evergreen trees can have yellowing leaves that won’t require any intervention from you while they settle into a different environment. There’s no need to panic; just take some time to consider whether or not the yellowing is natural or a sign of something more serious.
Why Is My Bonsai Turning Yellow?
So, why might your bonsai tree be changing color? Some reasons are perfectly healthy and part of the natural life cycle of the tree, whereas other causes might be more worrisome and require you to change the way that you are caring for the plant. It’s important that you consider which cause is most likely for your bonsai and how you are caring for it.
Your bonsai tree might be turning yellow because:
It is a Deciduous Tree
Most deciduous trees, regardless of their size, shed their leaves over the winter months, and part of this process is allowing the leaves to die off. The leaves stop producing chlorophyll (which is what gives them their green colour) and start to turn yellow, red, or brown before dropping away. This process helps the tree to retain valuable moisture and nutrition throughout the winter.
If your bonsai is a deciduous tree, like an Elm, a Maple, or a Ginkgo, and the weather is starting to get cold in the autumn, natural shedding is the most likely cause of any yellowing.
It is Under Stress
Even evergreen trees, which don’t shed every winter, will lose some leaves due to the stress of a new environment. Different types of soil, a change in atmosphere or temperature, a new kind of water, or different levels of light can all cause significant stress on a plant while they acclimatize.
If you have recently brought a new bonsai tree into your home, or you have changed something about the way that you are looking after a tree that you already have, some yellowing may occur while it is adjusting.
It is Underwatered
The first thing that most people think of when they see yellowing leaves is that the plant is probably not getting enough water, and that certainly can be the case. If your bonsai is underwatered, its leaves will start to wilt and curl up before any of them actually turn yellow or begin to drop off.
It is Overwatered
Surprisingly, a much more dangerous cause of yellowing in your bonsai tree’s leaves is overwatering. If the soil becomes saturated and stays too wet for too long, harmful bacteria can grow, and the roots at the base of the tree can start to rot. This is often accompanied by mold growth on the surface of the soil.
It is Not Getting Enough Light
Bonsai trees need to get a good amount of sunlight throughout the day, and the more light they get, the more green their leaves will be. Sunlight triggers the production of chlorophyll, so if your tree is not getting enough light, less chlorophyll will be produced, and the leaves can start to lose their green color.
It is Deficient in Minerals
Every bonsai tree needs to get a certain amount of minerals from the soil in order to grow healthily. If your tree is not obtaining enough nitrogen or iron, the leaves may start to yellow, indicating a deficiency. This is more common with older trees or those that have recently had a change in the type of soil they are living in.
How To Care for A Bonsai Tree If Turning Yellow
If the leaves of your bonsai tree have started to turn yellow, there are several things that you can do to help. It is important that you have identified why you think the yellowing is occurring before you make any changes, though, because you don’t want to inadvertently make the problem worse
If your bonsai is turning yellow, you can:
Wait And See
It might be that you don’t have to do anything at all, and your bonsai will be perfectly fine in a week or so. During a seasonal change or a minor adjustment to changes in the tree’s environment, a few shed leaves are perfectly healthy.
If it is normal for the species that you have at this time of year, or you are noticing just a few leaves turning yellow, it’s probably nothing to worry about but keep an eye on the other leaves in case they start to turn.
If your bonsai tree is stressed, it is better to avoid pruning for a while. Cutting, styling, and shaping are core parts of bonsai maintenance but overdoing it can add to the stress that your tree is experiencing. If you allow your bonsai to regain a bit of leaf growth, you can also see whether new leaves are sprouting healthily and looking green.
You definitely want to avoid overwatering, so you need to be sure that your tree is too dry before you increase how much you are giving. If the soil is very dry and your tree has wilted, on top of the fact that it has yellow leaves, then you might want to adjust your irrigation and start providing a little more water to the plant.
Decrease Watering or Increase Drainage
Overwatering is more of a risk than underwatering, as it is much more likely to actually result in the death of your tree. If a lot of leaves are yellow but still plump and full, it might be overwatered.
You want to make sure that water is not collecting around the roots of your tree, so providing better drainage will help, but you may also need to reduce the amount of water that you are giving to the tree.
You may also notice that your Bonsai’s leaves are turning brown. Here are the reasons why.
Move Your Tree
Some parts of your bonsai may be turning yellow in response to too much or too little sunlight. Losing leaves on one side may indicate that the tree needs to get more light on that side, and overall yellowing can mean it needs more sunlight in general.
You might consider moving your bonsai out of the house, as the vast majority will actually thrive better outdoors. Be cautious about when and how far you move your tree, however, as it can add extra stress while they adjust to the change.
Give Your Tree More Nitrogen
Nitrogen is really important for healthy growth and green leaves because it is one of the main components of chlorophyll. A lack of nitrogen can certainly cause leaves to turn yellow, so a nitrogen-rich fertilizer may reduce yellowing, but you should be careful not to overload your tree. Always select a fertilizer that is appropriate for the species that you have and follow the instructions carefully.
Give Your Tree More Iron
Sometimes a plant’s leaves will turn yellow as a result of an iron deficiency – this process is known as iron chlorosis. Usually, this is indicated by the development of yellow leaves that are covered in dark green veins. Iron chelate can help to provide your bonsai with some extra nutrition, but it should also be applied with care.
How To Prevent Yellow Leaves on Your Bonsai
If you haven’t yet noticed any yellowing on the leaves of your bonsai, there are steps you can take so that your tree’s leaves stay as green and vibrant as possible.
Choose an Evergreen Bonsai
Some species of bonsai will lose some of their leaves seasonally, no matter what you do, so you might want to choose a tree that is evergreen. There are many different evergreen bonsai trees that have green leaves all year round.
One of the most important things to do with your tree is to limit the amount of stress it experiences. Dramatic changes to their environment, or the way you are caring for them, are likely to cause stress for a bonsai, so try to be as consistent as possible and avoid over-pruning or unnecessary adjustments.
Water With Care
Getting the right balance when it comes to watering is somewhat of a lifelong battle for plant owners. You can investigate the exact needs of your bonsai species for general recommendations, but there are no exact rules.
Make sure that your tree’s soil can drain easily and never becomes saturated (don’t water the tree if the soil’s surface is wet), and don’t let the soil completely dry out or become parched.
Choosing the right spot for your bonsai can make all of the difference to its growth, and it is certainly easier if you get it right the first time. Make sure that they will receive a good amount of sunlight throughout the year, preferably on all sides of the tree, and consider keeping your tree outside if possible.
Ensure Healthy Soil
Sometimes the type of soil that your bonsai is planted in is out of your control, but having the right balance of minerals is still really important. Always buy a bonsai from a trustworthy source and keep an eye out for any signs of mineral deficiency.
Are Bonsai Trees Hard to Take Care Of?
Caring for a bonsai tree is not as challenging as many people believe it to be. Some bonsai enthusiasts use special tools and techniques to meticulously care for their trees every day, but the basics are relatively simple. Good amounts of sunlight, careful watering, and sensible pruning are not much more challenging for a bonsai than any other plant; you just need to be aware of their needs.
In Summary: Bonsai Tree Turning Yellow
Bonsai trees, like any other trees, will occasionally have some leaves that turn yellow. Often, this is a natural part of the seasonal shedding process or a minor adjustment that the tree is making to changes in its environment.
More serious reasons for yellowing in a bonsai’s leaves include overwatering (resulting in root rot), underwatering, mineral deficiency, or inappropriate levels of sunlight.
You want to identify the specific reason why your bonsai is showing some yellow in their leaves before you try to address the problem but, fortunately, most of the solutions are relatively simple. Once its needs are met, your bonsai will be green again in no time.