How To Thicken Bonsai Branches

How to thicken bonsai branches

One of the things I always seemed to struggle with when trying to design my bonsai tree was my skinny bonsai branches. I’d look at other people’s plants and see all these incredible designs, only to find my plant was lagging with thin branches and trunks. Luckily I found a few steps to thicken my bonsai branches. 

To thicken bonsai branches; grow sacrifice branches, use the scarring technique or plant your bonsai tree in the ground before you put it in a pot. Using the tourniquet or ring method can also work to thicken your bonsai branches but may permanently damage your bonsai. 

Growing more leaves through bonsai ramification and defoliation can also help increase the density of your bonsai trunk and branches. 

So which of these techniques works best? And what exactly do the experts say when it comes to growing out and thickening bonsai branches? Keep reading to find out more!

Just a quick heads up, over the past three years of running Plantpaladin, hundreds of people have asked for product recommendations. As such, You can find my favorite indoor bonsai tree here (link takes you to Bonsaiboy), my favorite outdoor bonsai tree (link takes you to Bonsaiboy), or have a look at all the products I recommend here

How to thicken bonsai branches? 

Whilst looks and aesthetics might be considered vain when dealing with people, having a beautiful bonsai tree that follows a natural taper is highly coveted in the bonsai community. 

Following the natural flow of a tree in the wild is one of the tenants of a good bonsai, and so having branches with a variety of thickness that tapers off the further out you get is an important part of keeping a tree. (better known as ramification)

All well and good for expert gardeners but how does the average joe (aka us) get thick bonsai branches and bonsai trunks? 

Luckily after countless wasted bonsai trees, blood, sweat, tears, and even a few insect stings, I’ve found the following methods work best to increase your bonsai branch girth: 

  • Grow out a sacrifice branches 
  • Use the scarring technique 
  • Plant your bonsai in the ground first 
  • Grow more leaves on your bonsai 
  • Split your bonsai trunk 
  • Use a bonsai tourniquet
  • Use the ring method 

Now I appreciate some of you reading this are still relatively new to keeping bonsai trees so these might be a little confusing. 

We shall explore these in more detail below, but to help with a quick summary, I’ve put these in a table below: 

Method to grow a thick bonsai branch 

Quick definition 

Sacrifice branches Sacrifice branches are when you grow out one branch for a period of time, usually two to three years without pruning. This then increases the girth of the trunk and the branch.  
Scarring technique Scarring in bonsai is when you make a vertical cut in the branches of your tree to thicken them. Use a carving knife for best results 
Grow your plant in the groundGrowing your bonsai in the ground means it will not be restricted by the soil in your pot. 
Split your trunk Making an incision in the trunk of your bonsai causes it to grow thicker, in turn forcing your bonsai branches to grow thicker 
Bonsai tourniquetsBonsai tourniquets force swelling in bonsai branches by cutting off the nutrients in them forcing the branches to thicken in size. 
The ring method Similar to bonsai tourniquets the ring method can be used to grow out more branches which can help in thickening the base branch. 

Let’s explore these below. 

Growing bonsai sacrifice branches to thicken bonsai branches

Easily the most common method used to grow out and thicken not only a bonsai trunk but also the branch of your bonsai. 

Sacrificial bonsai branches are branches that you grow out of your bonsai to help thicken branches, keep your bonsai under control, and strengthen your tree trunk. These sacrificial branches are grown for two to three years to help strengthen your plant after which they are removed. 

The general idea behind this is to grow out a branch for a period of time usually between two and four years. 

By not pruning or trimming this branch, it will have an uninterrupted stream of nutrients causing the sacrifice branch to grow thicker and longer than any of the other branches on your bonsai. 

After a few years, you can then trim this branch back, as it will likely be the branch that has the most girth on your plant. 

What is a sacrifice bonsai branch infographic

You can also grow out multiple sacrifice branches at the same time if your bonsai is in the early days to truly grow out and thicken your bonsai branches. 

Now, this is a subtopic all to itself so to help find out more, check out my blog post talking all about sacrifice bonsai branches

Use the scarring technique to thicken bonsai branches 

So this is another method that has been used quite a lot to make bonsai trunks bigger but can also be used to strengthen and thicken bonsai branches. 

To use the scarring technique to your bonsai then you need to do the following: 

  • Identity the branch or branches that you would like to thicken 
  • Mark the branches with a marker on the spots where you will scar the branches – if your bonsai is old and already has thick branches you might be able to get away with three or four scars per branch 
  • Using the carpenter knife, make an incision so the skin or bark of the bonsai has been removed
  • Aim to ensure that each scar is no longer than three or four centimeters – you never want to remove all the bark or skin from your branch 
  • Once scarred the skin will start to callus over growing back even thicker 
  • It may take about 2-5 years to heal completely – once healed you can repeat the process. 

Just be wary that you need to be careful with this technique as it can potentially damage your bonsai if you remove too much skin or make cuts that are too deep. 

Plant your bonsai in the ground first to thicken bonsai branches

Whilst the other methods can prove to be a little bit fiddly or time-consuming often I find that this method is the most impactful when wanting to grow and thicken bonsai branches.

You see, by planting a bonsai in the ground in your garden it has access to more soil and nutrients in the ground than it would be trapped in a little plant pot. 

We need to remember bonsai are just miniature versions of normal trees and so by planting it in the ground, your bonsai will grow into a full-on normal-sized tree if given the right circumstances and enough time. To summarize then: 

Plant your bonsai tree in the ground of a garden you have access and control of. Aim to grow your tree for one to two years, and your bonsai branches will thicken without growing into a large tree. Use this method for Chinese elms ficus or other species that are fast-growing. 

By planting our bonsais in a garden we have more access to the nutrients and water cycles meaning we can also further speed up this process. 

Split your branches to thicken bonsai branches

Another method traditionally used to thicken bonsai trunks but that can also be used to thicken bonsai branches is to split your bonsai branches. 

When your branches heal and fuse back together they will grow back stronger and most importantly thicker. 

It’s important however that we only use this method for our vertical branches as we do not want to interpret the flow of sap in the tree too much. 

Using a bonsai branch splitter then would be the perfect tool to do this then as trying to guess this by eye or using a traditional carving knife leaves too much room for mistakes.

My recommendation would have to be the Raguso Branch Splitter (link takes you to Amazon) which is incredibly durable and is made of steel. 

How to split bonsai branches

To split your branches then, use a sharp pair of branch splitters and make three or four sharp inspections on your vertical branches. You should press hard with your branch splitters until the metal pegs meet. Do this at the start of the growing season and by the end, you will find your branches will be thicker. 

Once again, avoid using this method with horizontal branches as you may not get the desired effect you want. 

How to use bonsai tourniquets to thicken bonsai branches

So the above methods should definitely work when trying to thicken your bonsai branches however every now and then, there will be plants who, try as we might, just won’t get any thicker. 

If you find yourself in this situation, no worries! I’ve got a few advanced methods to help thicken your bonsai branches. 

Starting with using bonsai tourniquets to thicken bonsai branches. 

Bonsai tourniquets induce swelling in your bonsai tree, cutting off the nutrients from certain parts of your tree. 

In turn, this will cause them to swell and force them to grow. 

To use bonsai tourniquets to thicken your bonsai branches, wrap copper wire that is about one-third the size of your branch in two to three loops around your bonsai branch. This will cause the branch exposed below the copper wire to swell. 

Now I appreciate this is a little more advanced so hopefully, the image below can help. 

Bonsai tourniquets explained

Use the ring method to thicken bonsai branches 

Similar to using bonsai tourniquets, the ring method also cuts off the circulation to your branches causing them to thicken. 

To use the ring method, cut off a one to two-centimeter ring segment of your bonsai branch skin all the way to the sap of your tree. 

Make sure this ring is large enough so that your bonsai cannot bridge or heal this wound. A minimum of one to two centimeters should be used but if your branches are already pretty big, you can go beyond this. 

When your bonsai branch does heal, it will grow back even thicker and even come with even more roots or branches further increase the girth of the original branch. 

Once again, I’ve enclosed an image below to help explain:

bonsai ring method explained

The science behind growing thicker bonsai branches 

So the above methods are all fantastic options to help thicken your bonsai branches but often at times I find that a lot of people rush to these techniques without actually doing the grunt work. 

At the end of the day, we need to look at how plants grow naturally in order to find the only truly natural way to increase and thicken the size of our bonsai branches. 

Trees grow in cycles, and while a lot of us think the more water or fertilizer we give our plants the better the results will be. The truth is the only real way to grow our plants is by photosynthesis and so the number of leaves our plants have.

Simply put; The more leaves a plant and sunlight our plant gets, the more efficient it is at photosynthesis and the faster it will grow. 

So how exactly do we get more plants on our bonsai? 

There are two main methods: 

  • Defoliation 
  • Ramification 

What is bonsai ramification?

Bonsai ramification is the process of growing, pruning, cutting, and finely dividing the small twigs and branches on bonsai, to give the appearance of larger trees. This is usually done by tapering your branches thinner the wider your plant gets.

By using bonsai ramification then we can actively grow more leaves as the more branches we have on our bonsai, the more leaves will also start to sprout, increasing the amount of photosynthesis a plant will get. 

Now, this again is a subject all unto itself so feel free to check out my blog post talking all about bonsai ramification

low bonsai ramification vs high bonsai ramification

What is bonsai defoliation?

To defoliate a bonsai is to either partially or totally remove the leaves from your bonsai tree. This is done using gardening scissors or shears where a cut is made mid-way up the petiole. This is so new leaves can sprout in the place of the old leaves, giving you bonsai a denser look. 

To defoliate a bonsai, use a pair of gardening scissors and cut the leaves from your bonsai about halfway on the petiole (the stem between your plant’s branches and leaves). Repeat this process until every leaf has been removed and in a few weeks, smaller healthier leaves will start to shoot. 

Now to find out more about defoliating bonsai, check out my blog post here

Once again, the more leaves we have the greater chance we have to get thicker bonsai branches. 

how to defoliate bonsai - infographic

A fantastic video that helps summarizes this can be found below: 

What other methods help grow thick bonsai branches 

Aside from the methods, we have laid out in the blog today there are a few other things we should do to ensure we maximize our bonsai care to get the thickest branches possible. 

This includes: 

What do the experts say about thickening bonsai branches? 

So while these methods have worked for me, I didn’t just want to rest on my laurels and give you what works for me so I called up two experts in the field of horticulture and bonsai and asked them about how they thicken bonsai branches – here is what they said. 

“The natural way is the best so ensuring your bonsai has enough room to grow and sunlight will always give the best results” Birmingham Botanical gardens 

“Any technique that works to strengthen a bonsai trunk can pretty much be used for bonsai branches” Homebase 

Why you should thicken bonsai branches 

Thickening bonsai branches will also strengthen and thicken the trunk of your bonsai tree. This will help keep your bonsai healthy but also make it easier to design your bonsai in the way you would like. 

Thick branches also mimic normal trees which is a key component for those who want their bonsai to look like miniature trees. 

My top picks for the gear you will need!

So like I mentioned earlier, over the past three years of running PlantPaladin, hundreds of people have asked me for my recommendations on the best bonsai gear on the market. 

Having spent thousands of dollars on bonsai items these past few years and tested at least 100 bonsai-specific products, I’ve listed my favorite products below – All of which I highly recommend and think you can get great value. 

They can purchase directly by clicking the link to take them to Amazon. 

Bonsai Tool Set: One of the significant challenges I’ve had is finding a toolset that was not only durable but didn’t break the bank. SOLIGT has recently developed a fantastic bonsai tool set that covers all the tools you need to trim, prune, and repot your trees. – You can grab it here

Complete Bonsai Set: Many of you will want to grow your bonsai trees entirely from scratch, but finding the varicose seeds, pots, and other items in one place can be challenging. Leaves and Sole then have created a complete bonsai set that I’ve personally used that ticks all the boxes. You can grab it here

Bonsai wire: The number of times I’ve run out of wire for my bonsai or purchased cheap bonsai wire that doesn’t do the job is embarrassing for me to admit. After a lot of trial and error, I found that using Hotop’s aluminum bonsai wire is one of the best options on the market. This can easily be used for both indoor and outdoor bonsai. You can grab it here.

Fehed Nicass

Fehed Nicass has been passionate about all things bonsai and botany focused for the past 3 years. What started out as a hobby has developed as a passion and he is now on a mission to teach and learn.

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