Sticky Mess: 2 Main Reasons Why Bonsai Leaves Become Sticky

  • By: Josh Koop
  • Date: April 1, 2022
  • Time to read: 6 min.
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If you happen to grow bonsai, you might occasionally notice a sticky layer on top of the leaves. Every bonsai owner has once thought to themselves: why does my bonsai have sticky leaves? There are a few things that could cause this, but don’t worry. You can bring your bonsai back to health pretty quickly.

Insects are known to be attracted to bonsai plants. Aphids and scales are the culprits behind sticky leaves among the insects that commonly harm bonsai. These insects leave sticky excrement on the leaf surfaces, giving them a textured appearance.

Thankfully, there are ways to get rid of aphids and scales on your bonsai plants. These insects do not affect your plants permanently. Moreover, the way to fix the issue is much easier than you might assume. So, let’s get into it!

How Did Your Bonsai Get Sticky Leaves? 

The main reasons bonsai plants attract these infective insects are their environment and health. Bonsai plants that you place outside for longer periods have more of a risk of inviting insects. Even though the plants remain healthier in outdoor environments, it can be a bit risky.

Then again, when it comes to their overall health, you have to be careful. Bonsai plants that are less than healthy can invite an infestation. So even if you keep your plants indoors, you have to regularly check up on their health.

Aphids On Your Bonsai Leaves 

Aphids are one of the main reasons bonsai gets the sticky texture on its leaves. The green-yellow insects are also known as ‘plant lice’. They do not only affect bonsai: they can also attack other plants.

The main reason why they are something you should be aware of is that, besides their excretion, they can carry diseases that harm your plants. 

Aphids work by settling on the leaves of the plants. From there, they can take out the sap from the plants and excrete the sticky waste.

Their sharp mouths help them extract the sap from the tree and the sticky substance known as ‘honey dew’ settles on the branches and leaves of the plant. 

How To Identify And Spot Them

Aphids can be of different colors. Usually, the insects are yellow, brown, green, grey, or red. They are tiny in size and settle under the leaves. Because of their position, it is hard to find them at first until they form visible swarms or leave honeydew. 

The best way to spot aphids growing on a plant is by observing the ants around the plant. Ants seek out honeydew to feed on. So if your plant has aphids on them, then the ants will likely be nearby the bonsai.

One other thing you should keep in mind is that honeydew can cause spots to form on the plant. These spots will be dark and greasy on the plant.

How To Know If Your Plant Has Aphids

The way to know if aphids are on your plant depends on your plant’s health. The ant movement might help, but it comes down to your bonsai plant showing the symptoms of being infested with aphids.

Here is what you should look out for when you do regular maintenance on your bonsai. 

  • The leaves will be sticky, and sometimes the limbs can be sticky too
  • Dark and greasy fungus on parts of the plant 
  • The leaves look unhealthy because of yellowing, wilted, or curling
  • The branches of the bonsai will be thinner or weaker 
  • If your bonsai has flowers, the flowers may fall off too early or deform

Stay aware of these signs when you do regular check-ups on your bonsai plant. If you do find most of these signs, do not worry. The way to solve this problem is not that hard.

But you have to get to work immediately to make sure the aphids can not do further damage. 

How To Get Rid Of Aphids From Your Bonsai?

There are numerous homemade methods to get rid of aphids from bonsai. Since it is such a common occurrence for aphids, most of these methods require stuff you probably already have lying in your bathroom or kitchen.

Let’s get into it. 

Washing

You can add some water depending on the size of your bonsai plant. Take the water and try to wash away the aphids from the leaves. Once you finish working the leaves, wash the branches and under the leaves to make sure there are no aphids or sticky substances remaining. 

There is a modification to this method that some people use. Use this with discretion because it is not highly recommended. You can take 1 part vinegar and 2 parts water to mix into a spray bottle solution.

Using that mixture, spray down your plant and wipe the moisture off after a while. 

Using Soap

Soaps are effective against aphids because they can kill the insects’ exteriors because of the chemical compounds in them. Dish soap, as well as insecticidal soap, is effective in this regard.

When using insecticidal soap, you can use it without too much water on the plant. It will not harm the plant, but it can leave some residue on the bonsai. 

When using this soap, do a patch test on the plant for 48 hours to see if it has any bad effects. If not, then go ahead and use it to get rid of the aphids. You might need to do this to the bonsai once every one to two weeks to make sure they remain healthy. 

Again, you can use dish soap as an alternative. Take water and a couple of drops of dish soap to form a mixture. This mixture is good enough to kill the aphids on the plant, even if it is not as effective as the insecticidal soap.

Always make sure to get every inch of the plant while cleaning.

Scales On Your Bonsai Leaves – And How You Can Fix It 

Scales are another kind of insect that can cause your bonsai plants to have sticky leaves. These insects are less likely to occur on your bonsai leaves. Yet, you should not rule out the possibility that there could be scales on your bonsai plant. 

Scales usually look white, yellow, or brown. They are very small in size. These insects settle on all parts of the plant, including the trunk of the plant.

Just like aphids, scales feed off plants and excrete the honeydew on the leaves of the plants. They will use the plants to extract sap for feeding and then produce waste. 

One of the ways you can identify scales on your bonsai is by watching out for the branches to lower. This means that they are getting weaker. While sticky leaves are a common sign, they can also suggest aphids. In the case of scales, the leaves will also get yellower and weaker. 

You can treat scales easily. Take your bonsai plant and a pair of tweezers. It is a bit of a time-consuming job. But you have to pick away at every scale on the plant individually.

While you can remove aphids with chemicals and washing, scales do not let you do that. Their shells are too tough for those methods to be effective on them. 

Conclusion 

Bonsai is a passion for a lot of people. And keeping it healthy and beautiful is the prime job of every bonsai owner. So, the next time you wonder why your bonsai leaves are sticky, refer to these tips to take your plant back to health.