How to make a bonsai tree trunk thicker

A tree’s trunk is essential because it provides strength and acts as a support. At the same time, a strong trunk allows the tree to grow up at the same height with the same resistance to buckling. So, how to thicken a bonsai tree trunk? I am going to talk about it in detail.

The tree trunk is its most essential part that attaches the crown of leaves to its roots. It helps the leaves to get the water and nutrients they need to make food from light energy.

When we talk about bonsai trees, thicker stems help them give support and get many nutrients and water from the soil. But, what to do to make them thicker? There are various techniques; I have listed below a few of them.

Thickening the Trunk of your Bonsai

Growing in the land

Bonsai trees don’t belong to a particular family of trees. Actually, they are full-size trees that are restricted to a small pot to keep them small. If you take out the tree from its pot and directly plant it in the ground, it will eventually grow to its standard size.

However, it takes many years to grow to its maximum height; therefore, numerous bonsai gardeners put their trees in the land for a short period to enable trunk growth.

When the tree trunk reaches the desired thickness, gardeners eliminate the bonsai from the ground and again plant it in a shallow pot to prevent rapid growth.

It may take several years for a bonsai trunk to thicken using this method. Therefore, peoples who use this approach prefer to use rapid-growing bonsai tree species, including Ficus Ginseng Bonsai or Chinese Elm Bonsai. Moreover, before planting the tree in the ground, you may have to consider and resolve potential problems.

  • Make sure your bonsai plant can survive all year round. For instance, tropical trees that need warm weather and high humidity can’t stay in severe winters.
  • If your bonsai tree is planted in soil that is not well fertilized, it will not grow properly. And if the soil doesn’t provide adequate drainage, you run the risk of root rot, which can eventually kill your bonsai.
  • Growing your bonsai tree outers can cause pests and diseases. Check your plant regularly so you can take the necessary measures needed.

Induce swelling

It is an ancient Japanese method used by respected bonsai masters. In this technique, you can use a wire tourniquet with the apparent intention of causing swelling.

When positioned right around the base of the bonsai tree, you can make a nice tapered trunk, even with trunks of tree species that are not naturally acuminated, for example, Chinese elms.

Remember that this method can give you results very quickly. If it is applied to fast-growing species, gardeners can anticipate seeing thicker trunks in the same growing season. However, it would help if you also remembered that this method is a permanent stain. Use it with caution and moderation.

The trunk merging

It is another way to build a thick trunk quickly. This technique is sometimes referred to as trunk fusion and can’t operate on existing bonsai trees.

Alternatively, you need to tie the trees of several plants together so that they ultimately merge and make the illusion of being one tree. The trunk merging technique perfectly works with fast-growing trees bonsai species such as ficus or Chinese elm.

Merging the trunk to thicken the trunk of a bonsai tree is not a traditional method, but numerous bonsai masters use this approach as it is the fastest way. But it takes a few months after the plants are tied to generate a thicker trunk. The way of trunk merging gives the gardeners more control over the design of the trees. They can map the size and start tapping quickly.

But there are some drawbacks of this method. For instance, if any plant dies during the fusion procedure, it can leave space in the stems and prolong the fusion time.

So you have to ready some plants to replace if any dead tree. It will eventually affect the charm of your bonsai tree as there may be several different plants on each side of the tree. One plant can overwhelm resources and cause the death of other plants. It is essential to ensure that all trees have enough water, light, and nutrients for growth.

Sacrifice branches

Another popular way to thicken the trunk of a bonsai tree is to use sacrificial branches. This technique focuses on planting a side branch close to the trunk’s base that will supply it with many nutrients, leading to the thickening of the tree trunk.

The side branch is planted while the rest of the tree can be cut down and restricted. When the bonsai stem gets the preferred thickness, the additionally added branch is eliminated to trim and shape the bonsai. This method does not demand to plant the bonsai tree in the ground and is an excellent choice for gardeners with limited area.

The sacrifice branches approach also takes many years to thicken a bonsai tree trunk planted using this technique. The branch on either side can be used as a sacrificial branch. But the branch you choose must be very thick and put down a significant stain. The bonsai masters are working for many years to heal the cut of the bark.

For the sacrificial branch to grow, you will have to wire the extension to become straight. Pick a branch in the middle of the trunk, and as the stalk grows, it adds girth to the trunk below the point attached to it. Nothing above the sacrificial branch will be thick. This is a great way to make a tapered trunk.

Cutting the trunk

It is better to plant a tree in the ground for this technique. It is definitely one of the fabulous ways to make a thick trunk and a great trapper for your bonsai tree.

The first big cut you have to make is along the trunk, where it has got the desired thickness from this tree. It is essential to ensure that you don’t cut it too small or too large on the tree.

After that, you need to wait until the plant starts growing. Then, you have to pick a branch to wire vertically, as this branch will form the next stage of the trunk. To thicken the bonsai bottom, be sure to keep the other branches moving around for the foreseeable future.

Split the trunk

Isolating the bonsai stem is the fastest way to get the trunk thickness. With this approach, you will have to split your bonsai stem below the middle and use wires to separate the two ends of the trunk as it heals. Isolating bonsai trunks yield almost immediate outcomes.

It should only be applied to trees that can accept this treatment. Suggested bonsai tree species are Chinese elm, juniper, boxwood, and ficus. In addition, this technique should be applied at the start of the growing season

You have to eliminate the bonsai plant from its shallow pot and keep it upside down. Using a saw, start splitting the trunk in half until you are halfway there. When you replant a bonsai tree, separate the stem or wood penny from the two parts of the stem.

It’s better to grow a tree in a large pot to facilitate the healing process. It will make your bonsai tree look like a thick stem, and it takes years for this stem to heal completely

Bend to grow

It is the last but definitely an excellent way to plant bonsai with a good, thick trunk. This bend to grow technique will only work with bonsai species with many side branches, as you may be using.

First of all, you have to allow the growth of this tree at the end of the growing season, at the point where you want to bend the main trunk down instead of turning the vertical branch upwards.

Within a few months, it will give the bonsai a tapered trunk as the side branch will solidify slower as compared to the main trunk. Once the bonsai trunk gets the desired thickness, you can either leave the central ark as a sacrificial branch for a while or cut it out.

The problem with trimming it is obviously a big stain that will be noticeable on bonsai. Therefore, it is recommended to use some woodcutters and cut the tree to ensure that the stain is on the back of the tree.


Hence, I have shared the most widely used bonsai trunk thicken techniques because developing a tapered trunk is significant for the charm and growth of your bonsai plant.

However, in the above-mentioned techniques, some of them take several years to show the desired results, while others are extra fast.

So it depends on you, for which you go. I hope this piece of article will prove beneficial for you and i also strongly recommend you learn how to grow bonsai moss too.

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