Why Are The Leaves On My Bonsai Tree Sticky?

A good friend of mine asking me about why the leaves on his bonsai were sticky and what I do to about sticky leaves on my bonsai trees. In all honesty, I had to do some research because I had never heard of this before and certainly never seen it on my trees.


Scale pests are usually the cause of bonsai trees having sticky foliage. The reason the foliage feels sticky is due to the ‘honeydew’ the secrete. The scale insects are similar to mealybugs but have a hard shell. Let’s find out more…


Why Your Bonsai Tree Foliage Feels Sticky


It’s not your imagination and no, you didn’t spill a drink on your tree, it really is sticky. That’s unfortunately because of tiny scale insects or maybe even aphids. They’re pretty annoying it seems, all they really seem to do it suck the sap out of bonsai trees and other house living plants.


The sticky feeling is because of what the insects secrete, known to gardeners as ‘honeydew’. The majority of the time the owner would have no idea about the scale insects or aphids even being around as they’re sometimes extremely hard to spot – not the most obvious creatures.


Aphids Or Scales?


Distinguishing which is on your tree isn’t really the most important thing in the world as they’re both treated in the same way.


Scales are tiny insects, without wings, that live on the branches of bonsai trees. Aphids come in different colours, either brown, green, grey or red and they will usually not have wings. Aphids will tend to live on the underside of leaves.


I learnt a pretty cool tip – look out for ants when routinely checking over your bonsai tree. It’s said that ants are usually present when the honeydew is around, due to them feeding from it.


How Does Your Bonsai Get Aphids?


I’ve learned that there are only two ways your bonsai tree can actually get aphids.


  • Your bonsai already had them – from a nursery stock plant or if you’ve bought the bonsai etc.
  • They flew onto your bonsai from outdoors.


Keeping your tree outdoors can obviously increase the risk of catching insects like aphids but still, as most bonsai enthusiasts would tell you, the rewards for having the bonsai outside greatly outweighs the risk of things like sticky leaves.


What Can You Do About It?


Thankfully, this isn’t going to be the death of your bonsai tree. Scale and aphids, as annoying as they are, aren’t really too dangerous to the health of your tree in the long run. That being said, it’s still the best course of action to treat them as soon as possible to avoid any possible risks.


  • Take your bonsai tree outside.
  • Wash the tree gently with water, making sure you cover all areas including the branches and underside of leaves.
  • Use a solution of water and a few drops of dish soap to cover the bonsai tree. This will cover the insects and kill them.
  • Use a wet cloth to wipe the tree down.


It’s really that simple. You should notice that over the coming weeks you won’t have any sticky leaves and leaves will stop turning yellow and dropping off.


Another way to kill the scale and aphids, although I really would recommend it, is to use vinegar. If you fill up a misting bottle one third with white vinegar and two thirds with water, when sprayed it will kill the insects instantly. People often use this technique with houseplants but in all honesty I wouldn’t be quick to recommend it with a bonsai tree, the best course of action, by far, would be the water with a few drips of dish soap.


If after a few weeks you are still having a problem, I would definitely recommend creating a forum post about it and seeking more help as it maybe worse than just scales and aphids.


It’s worth noting that a healthy bonsai is much less likely to have an issue withstanding diseases and insects that come its way. Prevention is the best policy. Ensure that you’re constantly keeping your bonsai tree healthy, pruned and consistently check for any infections or insects in the tree.