Why Does My Bonsai Tree Have Sticky Leaves?

You’ve been caring for your bonsai tree and ensuring it has enough water, sunlight, and nutrients. During your daily inspections, you check the foliage and notice that the leaves feel pretty sticky. Did something get on your tree? Sticky leaves on your bonsai tree are not something to ignore. It can be a sign of a more serious issue.

Sticky leaves on a bonsai tree are usually caused by one of two insects: aphids or scales. They release a sticky substance, known to gardeners as honeydew, on the foliage that leaves it sticky to the touch. Luckily, there are ways to treat your bonsai and get rid of these pests.

How Did My Bonsai Tree Get Pests?

Although some varieties of trees are more susceptible to pests, bonsai trees get pests due to its environment.

Pests can fly on your bonsai tree if it is placed outside or if it’s near other infected plants. There are many benefits to growing your bonsai tree outdoors so continue to regularly check your tree for a potential infestation. These insects look for weak trees so it’s important to keep your bonsai tree healthy. You can protect your bonsai by practicing proper pruning, re-potting, and watering techniques.

How Do I Know If My Bonsai Tree Has Scales Or Aphids?

If your bonsai tree’s leaves are sticky, either scales or aphids are present. Bonsai tree pests will cause severe damage if left untreated. These insects can cause your tree to lose its branches and leaves. Over time, the insects can even kill your bonsai tree.  

When you notice that your bonsai has sticky leaves, there is a high chance that you have aphids. Aphids are far more likely to be the culprit. For that reason, we will cover the basics of scales and the remainder of the article will focus on aphids.

Does My Bonsai Tree Have Scales?

Scales are small insects that take the sap from the tree and produce a sticky substance which acts as a protective barrier for them. These pests will appear on your bonsai as small bumps on the leaves, branches, and trunk. They can be white, yellow or brown.

Photo Courtesy of Wikipedia


  • Bonsai branches begin to droop
  • Leaves wilt and turn yellow
  • Leaves are sticky

How To Treat Scales

If your bonsai tree has scales, it’s best to remove the insects individually with tweezers or with your hand. Due to their protective shells, chemical pest treatments are not as effective on scales.

What Are Aphids?

Aphids are far more common on bonsai trees than scales. If your bonsai tree has sticky leaves, more than likely, it will be aphids. Aphids are commonly referred to as “plant lice”. Aphids are typically green, but they can also be grey, brown, yellow or black. They are shaped like a teardrop. Aphids are dangerous to a bonsai tree because they carry and transmit many diseases.

Aphids will use their sharp mouths to attach to your bonsai tree. The insects will consume the sap from the tree and leave sticky waste droplets, called honeydew, on the foliage and limbs. 

Aphids can be harder to spot because they hide and reproduce on the underside of the leaves. One clue that your bonsai tree has aphids is the presence of ants. If you notice more ants around your tree, there’s a chance that aphids are also around. Ants are attracted to the sticky, sugary honeydew that the pests produce.

Honeydew also attracts sooty mold spots which result in greasy, dark blemishes on your bonsai.

Photo Courtesy of Wikipedia

How Do I Know If My Bonsai Tree Has Aphids?

Your small bonsai tree can host up to 200 aphid species and it’s important to know when your tree has been exposed. An undiagnosed bonsai tree can take a big physical toll from an aphid attack.  


  • Branches are curled or look weak
  • Leaves will curl, wrinkle, distort, wilt, or turn yellow or brown
  • Flowers are damaged, deformed, or fall off the tree
  • Leaves are sticky
  • Black sooty mold fungus

How Do I Treat A Bonsai Tree With Aphids?

Once you’ve identified that your bonsai tree has aphids, you’ll want to treat it quickly. Because aphids carry many diseases, you don’t want to risk your bonsai’s health.

Traditional aphid treatments for larger plants can also be successful on bonsai trees. There are several ways to treat aphids:


The easiest and most budget-friendly method to treat aphids is by spraying your bonsai with water. Before spraying your bonsai, ensure each branch and stem is supported. Place the tree in your sink and use a faucet sprayer attachment to spray down the tree. If you are working outdoors, you can use a hose, but be aware of the water pressure so you don’t break any branches. The pressure from the water will knock the insects off your tree. It’s important not to knock them off into your bonsai’s soil. If aphids are in the soil, they will continue their attack.  

Some gardeners choose to mix vinegar in their water before spraying down their tree. Treating your plant with a vinegar mixture can be even more effective than just water. The mixture should be 1-part vinegar and 2-parts water.

After you’ve sprayed down your tree, you can wipe down your bonsai with a wet cloth. You should continue treating your bonsai tree for a few weeks until there are no more signs of pests.

Insecticidal Soap

If you find that your tree needs more than water to treat aphids, you can use insecticidal soap. Insecticidal soap uses active ingredients like soap salt to create a chemical compound that kills soft-bodied pests like aphids, mites, and mealybugs. When applied directly to aphids, insecticidal soap kills them by causing their bodies to leak out. Insecticidal soap is only effective when it’s wet so multiple applications may be necessary. If you are looking for an insecticidal soap, we recommend an organic brand like Safer Brand 3-in-1 Garden Spray Concentrate.

Commercial insecticidal soap kills aphids without leaving toxic residue on your bonsai. Before treating the entire plant, put the soap in a small area of your tree and wait 48 hours to see if there is a reaction. If your test area is clean, the soap is safe to use. You’ll want to water your plant before using the insecticidal soap. Depending on the type of soap, you may need to conduct follow-up treatments every seven to ten days. This ensures that you eliminate any offspring.

Introduce Other Bugs

Another approach to removing aphids from your bonsai tree is to introduce bugs that prey on them. This natural approach involves buying or encouraging predatory bugs to come and eat the aphids. Many gardeners recommend using ladybugs, but you can also consider other predatory bugs like spiders and praying mantises. In some areas, you can buy these bugs in local gardening stores and bring them to your tree.

It’s best to refrigerate your ladybugs before releasing them at night. Mist down your bonsai tree and the beetles to prepare for the transfer. Place the ladybugs at the base of the bonsai. The bugs will climb up the tree and start hunting for aphids. If you’re treating a severe infestation, you may need to release another group of ladybugs within the week. 

If purchasing bugs is not an option, you can buy plants that will attract these predatory bugs naturally like dill, alyssum, geraniums, and angelica.

Final Thoughts

If your bonsai tree has sticky leaves, it’s more than likely aphids. Sticky leaves a result of a substance released by the insects called honeydew. Aphids can cause a lot of physical damage to your tree including cause leaves to fall off, weakening branches, and encouraging mold. There are several ways to treat aphids. The most cost-effective way is spraying down your tree with water. You can also use a ready-to-use insecticide soap or introduce predator bugs that will hunt the aphids. The best way to prevent aphid infestations from escalating is to routinely check your bonsai tree. Pay close attention to the underside of your leaves because that’s where aphids hide and reproduce. When treated quickly and effectively, you can minimize the harm caused by aphids.

Learn More About Bonsai

Growing a bonsai requires horticultural skill, artistic skill, patience, and dedication. Bonsai trees are fragile pieces of art that need constant and proper care. 

As a bonsai artist, you will need to have an extensive understanding on topics including: 

* How to get started 

* Bonsai History  

* Major Bonsai Styles 

* Bonsai tree species

 * Bonsai specialty tools 

* Healthy, Aged appearance

* Trunk line & Branching Patterns

* Potting your Bonsai

*Wiring and Shaping

* Pruning

* Watering & Fertilizing

* Repotting  & Seasonal Care

* Displaying your bonsai

If you want to learn these topics quickly and ensure that your bonsai trees thrive, check out this easy-to-follow guide on How To Grow and Care for a Bonsai Tree.

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