A thick trunk on your bonsai tree is probably one of the most visually appealing factors your tree can have. A thick, gnarled trunk on your bonsai tree will give the impression that the tree is very old and has been through a lot. If you are new to bonsai or just wanting to know a little more take a look at this article to get some extra knowledge about bonsai in general. Let's take a look at some of the different ways you can thicken up your bonsai tree's trunk.
Planting your tree in the ground
The oldest, and most common way people go about thickening their bonsai trees is by planting it in the ground. This will allow the roots to spread out and grow allowing the trunk to get a lot bigger. This is also one of the most reliable ways to to go about making a thicker tree.
After your tree has been in the earth for a while you can put in back in its normal pot or you can put it in a pot that is a little on the larger side. Of course you can do this from the beginning and skip planting it in the ground if you prefer. The tree will not grow as fast this way but, this will allow your tree to continue growing and getting thicker in the process. The only downside to doing this is you will have to monitor your water and fertilizer levels a lot more carefully than you normally would. After the tree has been in the pot for a while you can transfer it back to its original sized container.
Applying a tourniquet to your tree
Applying a tourniquet to your tree is probably one of the fastest ways to see results, which can be noticeable in just one growing season.
To go about doing this, wrap a wire tightly around the base of your tree. Doing this will your tree to swell up, and produce a much thicker trunk, although it does come with it's draw backs. One side effect is the wires will leave a permanent scar on your tree which many people find visually unappealing. I personally kind of like the way the scars look on the trunk, but to each his own.
Intentional cuts in your tree
Another method you can go about would be making small cuts into your tree to promote trunk growth. This is done by making small incisions with a knife into your tree vertically, until you reach the sap layer. After this is done, the tree will heal the woulds creating scar tissue, thus adding more volume to the trunk.
You can thicken a trunk at the just the base by carving two or three cuts around the circumference of the trunk and letting them heal up. This will promote larger trunks and just a better visual appearance in general for your tree.
Some controversial methods
There are some not so main stream methods of getting a thicker trunk for your bonsai tree. Some of these can be unsafe to your tree, or possibly kill it if done incorrectly, so use these practices to your own discretion.
Hammer on the base of your tree. Yes, it's exactly as it sounds like, just take a hammer and start hitting the trunk of your tree with it. I personally wouldn't recommend anyone to do this, but it can be done successfully, producing amazing results. These are trees we are dealing with and they can stand a lot more stress and damage than you might think. I knew of this one tree that was planted in a weird place so all the cars trying to park next to it ended up hitting it. After a while, the tree started to get huge at the bottom as a results from the cars, so I could see how the hammer method could work.
Drilling into your tree. Yes, this is just like it sounds also. All you need to do for this is just take a drill, and drill a small hole into your tree. I personally would never do this, and don't recommend anyone to try this, but I have seen it done before and with amazing results. If you do decide to try this, practice first on a tree that you wouldn't be too heart-broken if it died.
In conclusion for your bonsai
If applied properly,these methods and techniques can prove to be very helpful in improving the visual appearance of your tree by increasing the circumference of the trunk. And as always in life, happy living and best of luck
-Brandon The One
john b good on May 29, 2019:
Mit Street on June 08, 2016:
Whilst I have been very interested in Bonsai for 50 years, I have been seriously ill with a chronic condition all this time. In my 20 s I had a hundred or so trees, but I did not have the funds to go deeper into Bonsai cultivation. But all from tiny saplings pulled from the ground. I found this article quite useful. I have another collection now with good trees and some yamadori. All my work is done in pots, big and small. Increased girth is not often covered in books so well done for your basic introduction. Thank you !