Bonsai Size: Why Are Tall Trees So Incredibly Small

  • By: Josh Koop
  • Date: February 8, 2023
  • Time to read: 6 min.
Affiliate Disclaimer

As an Amazon affiliate, we earn from qualifying purchases. I prefer to be honest and upfront with my readers that this doesn't change my beliefs in products nor services!

If you are familiar with the art of bonsai, then you definitely know how small these plants can be! Actually, the size of the plants is what makes them more beautiful! If they were taller, they would be like any other typical tree. Now, as a beginner or even an enthusiast, you may wonder why do bonsai trees stay small? 

To be fair, the process of cultivating bonsai and the various techniques used in the process ultimately give rise to the beautiful size of bonsai. Some unique methods used in the entire process cause the plant to be miniature!

However, you must get to know these techniques that make the plant stay so small! Also, you may wonder, will these plants ever grow taller? And what should you do to keep them smaller for eternity?

In this article, I will explain all these facts in detail. So, to have a brief overview of all these facts, please read the entire article till the end.

Do Bonsai Plants Grow Taller?

Bonsai plants grow in whatever environment you allow them to. If you maintain the proper methods of producing bonsai, your plant will retain its miniature form forever. However, if optimum conditions are ensured, the same bonsai can grow taller !

The first thing you need to understand here is that everything in nature can grow if it is given optimum conditions. A child develops his ability to speak when he gets to learn from his surroundings. But if the same child doesn’t hear anyone speaking, it becomes difficult for him to form words or even utter them. 

Likewise, a bonsai is a child of nature that needs to be taught to stay in its shape and size. Aa Bonsai is not any particular kind of plant. It is like a regular plant that you grow in small containers with limited resources to create this shape and size.

Yes, there are species that grow better in the form of bonsai . But any plant can be transformed into a bonsai . That is to say, if you ensure adequate resources and other requirements, any plant can grow into a miniature size.

Actually, some of the main techniques are growing plants in small pots or containers, pruning the leaves and roots on time, repotting, etc. These methods allow the plant to grow to the desired size!

However, if the same plant is made to grow in a more extensive ground, or say like any other regular tree, it will exceed its status as a Bonsai. Even an elm bonsai tree that was grown on the ground will eventually grow into a giant plant.

So, yes, bonsai plants can grow taller if you let them. But then again, it varies from species to species.

The Biology Behind The Size Of Bonsai Trees 

Now, let’s get to know how the bonsai trees maintain this size. Yes, in simple words, watering less or growing in small containers can create this miniature. But the fundamental biology behind this process is more complex.

The growth potential of a plant or a tree depends on several factors. Among them, the notable ones are- the amount of watering, the amount of sunlight the plant is getting, proper aeration, pruning, defoliating, cutting, etc.

So, let’s get to know in detail the biological explanation of all these factors for a bonsai!

Growing In Small Pots

The number of nutrients that an entire field of soil can hold cannot be contained in a bucket of soil. Also, a tree cannot spread its roots in a small pot in the same way it can in an open ground.

For proper growth, the roots need to spread evenly to grasp the nutrients from all directions.

So, when you grow a plant in a pot or a small container, you are confining its growth to the pot. The plant can take up only as many nutrients as the soil offers. Hence, growing in small pots can limit the growth of bonsai.

Watering Only As Much Required

Water is one of the three essential elements a plant needs to grow. If you limit the amount of daily allowance for water, the growth will not be the same anymore.

Of course, you should do it in amounts that do not harm the plant. If you limit the water more than necessary, your bonsai may expire soon !

So, water the trees only as much as they need. Do not go overboard or do not do less. Just water the exact amount to get the desired shape and size. Usually, it varies from plant to plant.

So, know your species first, then decide the right amount.

Growing A Sacrificial Branch

Basically, a sacrificial branch is a branch that is allowed to grow a maximum amount so that the growth of the other parts remains saturated evenly. 

Suppose you let one branch in the middle of your tree grow for a certain period of time. During this period, you will have to prune the other parts regularly. Through this process, you are limiting the growth of the tree as a whole. 

Of course, you will have to trim off this branch later on. Hence, the name ‘sacrificial branch’ was coined. However, make sure you are not cutting off a growth bud in the process. Otherwise, you might end up stunting the growth of the plant forever!

Excessive Sunlight 

There is a law of biology that says when you keep plants under strong direct sunlight for an extended period, they tend to produce smaller leaves.

This is due to the fact that, when there is excessive sunlight, the plants require less surface area, and so the leaves don’t grow much. Hence, the plants produce smaller leaves.

However, if the same plant is kept in a darker place or a place where there is little sunlight, it will grow larger leaves. Almost all plants follow this law of biology, and bonsai is no exception to this. 

Of course, there are species that have smaller leaves naturally. The Chinese Elm, Oak, Linden, Willow, etc., have naturally smaller leaves.  So, if you want to grow a smaller bonsai , you will prefer to use these species to get the best results!


It simply means removing or deleting the first layer of foliage from your Bonsai. It is different from pruning in the sense that you have to prune your plants regularly.

But it would be best if you defoliated once a year. And you have to defoliate the first foliage of the year. That’s the rule. It will limit the size of the leaves when they grow again.

But it would be best if you were careful not to defoliate a conifer plant. Because if you do so, the new foliage hardly ever grows back. So, studying the species is very important!


It will help if you prune your Bonsai regularly . Many people often think that pruning will impede the growth potential of a Bonsai . But this is a misconception. In fact, pruning the roots and shoots always encourages new growth. 

A Bonsai plant has the exact same size of cells as that of a regular average tree, and even in some cases, the cell size is bigger! So, if pruning can encourage the growth of any regular tree, it will work for Bonsai too. 

Besides, it would be best to regularly prune the dead leaves and shoots and the worn-out roots. Otherwise, these may act as barriers to the plant’s growth overall.

But be careful not to cut out the apical buds, as these are the growth originating points. So, be careful when you prune.


It is an exciting aspect of growing a bonsai . Repotting means transferring a bonsai from one container to another. When you move a bonsai to another pot, the bonsai has to cope with the new environment. The soil changes, the surface area changes. Overall, the atmosphere is new to the plant.

So, to some extent, this method can restrict the growth of the bonsai. It works better when you transfer the plant from a more oversized tray to a smaller pot. The limited surface area can confine the growth better.


The art of bonsai has always been a mystery. These trees are wonderful, no doubt about that. But the actual beauty lies in the shape and size of the tree!

Only the optimum conditions can ensure the miniature beauty that you desire. So, if anyone asks you now why do Bonsai trees stay small, you know what to tell them!

I hope this article helped you to understand the mystery behind the shape and size of bonsai in detail. Thank you for reading the entire piece with patience.

Have a nice day! Happy gardening!