How fast do indoor bonsai trees grow?

Growing a bonsai tree is a Japanese art that has been around for thousands of years. It can be a rewarding hobby for anyone looking to work with their hands. Bonsai requires advanced horticultural skills, daily commitment, and, of course, patience. If you plan to grow a bonsai tree, prepare to make a lifelong commitment to your plant.

If you’re starting a bonsai tree from a seed, be prepared for a long journey. It can take anywhere from 10 to 15 years to grow a bonsai tree. As a bonsai gardener, you need to ensure that your tree has the proper growth conditions to develop a root system along with a thick trunk and limbs.

Luckily, there are ways to speed up the bonsai growing process. In this article, we’ll provide seven tips on how to make a bonsai tree grow faster.

1. Look For Young Trees

One way to shed years off the bonsai growth process is to start with a sapling. A sapling is a young tree with a thinner trunk. Saplings are the perfect size for bonsai and you’re already years ahead of schedule compared to starting a tree from a seed.

Bonsai trees are just normal trees that are pruned and trained to remain small. That means you can choose just about any tree variety to bonsai. Keep in mind, there is a list of preferred tree varieties that can thrive with aggressive pruning and living in a small container. Some preferred bonsai tree species include junipers, pines, Japanese maples, and Chinese elms.

There are several factors to consider when choosing a sapling tree. The sapling you choose should be proportionally appropriate for bonsai. An ideal tree will have small leaves or needles and the trunk should be naturally tapered, in other words, the trunk should be wider on the bottom and gradually become narrower on the top. Also, check the length of the branches to ensure that the lower branches are the long and the higher branches are shorter. Avoid choosing a sapling with large leaves or a weak trunk. Ideally, the sapling you choose should already have a natural, mature appearance before you start pruning and shaping it.   

Choose saplings that are growing in a 1-gallon container. Typically, trees of this size will already have a more mature root system and a thicker trunk, two things that take years to properly develop. If needed, you may need to grow the tree for an additional year so the branches can grow long enough for the first pruning session.

There are a few steps to take to prepare a sapling for bonsai. You will start by gently remove the sapling from its original pot (if you purchased it) and begin removing excess soil from the roots. Be cautious not to break the main stem.

Before repotting the sapling, you’ll need to prune the roots. By pruning the roots, you slow down its growth, so the tree does not quickly outgrow their shallow container. After pruning the roots, you can place your sapling tree in your bonsai container. You should give your new tree up to two to three weeks of rest before pruning the top.

Choosing to start a bonsai tree with a sapling sheds many years of waiting for the plant to be big enough for pruning and wire training.

2. Choose Fast-Growing Trees

If you’re a bonsai gardener in a time crunch, choose a fast-growing tree species to speed up the process. Fast-growing trees are great because it is significantly easier to shape and train them. Choosing a fast-growing tree species can shed many years of wait time while the tree develops its roots, trunk, and branches.  

There are several fast-growing tree types such as deciduous, evergreen, coniferous, and succulent trees. By choosing any of these tree types, you can choose trees that flower, have leaves all year round, or come in a variety of colors and unique shapes.

Some fast-growing tree varieties for bonsai include Chinese junipers, Japanese black pine, boxwood shrubs, jade plants, snowdrop trees, and maple trees. 

There are many different tree varieties to choose from that can suit almost any lifestyle. When choosing a tree variety, consider where your bonsai tree will be located. Will you keep your bonsai tree indoors or outdoors? Some tree varieties are more sensitive to colder climates and will need protection from the elements. Fast-growing bonsai trees also require more care and attention compared to slower tree varieties.

3. Maintain Tons of Thin Roots

Bonsai trees require some rootwork to live a healthy life in a shallow container. Because of the limited water and nutrients stored in the small pot, roots will continue to grow in search of more. In a shallow pot, a bonsai’s roots will grow in one area. If left unpruned, the container can become saturated with roots and the soil will dry out significantly quicker. That’s why it is important to trim the plant’s roots to ensure it remains healthy enough to continue to grow at a fast pace. If the plant’s health is declining, you risk it slowing down its growth.

The environment determines how frequent a gardener will need to prune a bonsai tree’s roots. The growth rate of the tree is also a consideration. Slow-growing trees may only need to have their roots pruned once a year. If you have a fast-growing tree species, you will need to prune the roots more frequently.

It’s best to prune roots during the slow growing season, usually in the late fall or early spring. Root pruning can shock a plant so the slow growth season helps reduce the stress on a bonsai tree. 

Pruning a bonsai tree’s roots is simple for beginners. Begin by removing the plant from its container and gently remove any excess soil from the roots. You can use your hands or a gentle brush.

Inspect the bottom of the tree and begin to cut any large, thick roots that you see. It’s important to remove larger roots from your bonsai tree. Ideally, you’ll want many small, thin roots because they are more efficient at absorbing water. Roots should be trimmed all over so the cluster of roots fit in its new container without having to fold over.  

Anytime you perform root pruning on a bonsai tree, the tree needs to immediately be thoroughly watered to help with the shock. Regularly pruning a bonsai tree’s roots is one way you can make a bonsai tree grow faster. 

4. Thicken the Trunk ASAP

After developing a root system of many small, thin roots, the next important step of growing a encourage the growth of a thick, tapered trunk. Growing a thicker trunk can take a long time, sometimes up to five years.

A bonsai tree needs to have a thick trunk because serves two purposes. First, the trunk supports the entire tree against the elements. Second, the trunk transports water and nutrients to the foliage and moves carbohydrates from the leaves to the roots. A thick trunk will ensure the longevity of the bonsai plant.

There are a couple of methods you can use to thicken a tree trunk faster. By far, the fastest trunk thickening method is to split it. Splitting a bonsai trunk will provide instant results. With this technique, you will physically split your bonsai trunk down the middle and use wires to keep the two halves of the trunk separate as it heals.

Another fast method to thicken a bonsai tree’s trunk is trunk merging. With this method, you are not using an existing bonsai tree but rather using several saplings. This untraditional method requires you to tie together several saplings so they can eventually merge and create the illusion of becoming one tree. When paired with a fast-growing tree species, the merging can take only a few months.

Thickening a bonsai tree trunk is an essential step in making a bonsai tree grow faster. It is a time-consuming process that can take many years. By using the trunk splitting or trunk merging methods, you can speed up the growing process and focus on shaping the tree significantly sooner.

To learn about more techniques on how to thicken a bonsai tree’s trunk, see our article: How To Make A Bonsai Tree Trunk Thicker.

5. Maintain A Balanced Diet

Plants need a lot of nutrients to grow and remain healthy. Because of its limited root structure, bonsai trees do not have enough space to get the nutrients and oxygen it needs. Because of this, bonsai trees will need an additional source of nutrients in the form of fertilizer.

Fertilizers give a bonsai tree the vitamins and minerals it needs to turn carbon dioxide and water into food. Routine fertilizing will keep your bonsai tree in its miniature size and prevent it from growing weak, thin branches.

Fertilizers are composed of three elements that are necessary for plant growth: Nitrogen (N), Phosphorous (P), and Potassium (K).

Nitrogen will help a bonsai tree continue to grow its branches and foliage. Potassium will provide the nutrients needed to produce flowers and fruit. Phosphorous nourishes and strengths a bonsai tree’s root system. High-quality bonsai fertilizers will have an NPK value to help gardeners understand the composition of nutrients and choose the best brand for their tree.

Due to the limited space in its container, a bonsai tree will need a lot of fertilizer during its growing season. If you want to know how to make a bonsai tree grow faster with fertilizer, you need to ensure you feed your plant on a regular schedule. During the growth season, be prepared to feed your bonsai weekly. When you notice the growth rate of your tree slowing down in the late summer, it’s time to reduce feedings to once per month.

Make sure you understand how and when to feed a bonsai tree. Your bonsai tree should be healthy enough to receive the fertilizer. If the bonsai tree is sick, you need to shift your focus from growing your tree as fast as possible to making your tree healthy again. With proper fertilizing, you can expect to make a bonsai tree grow faster and remain healthy in the long run. 

6. Bigger Pot = More Growth

Routinely repotting a bonsai tree will provide more nutrients to your plant and ultimately result in a bonsai tree growing faster.  

A gardener will determine how often they need to repot a bonsai based on the size of the container and the tree species. If you choose a fast-growing tree, expect to repot the plant every one to two years. The older the tree gets, the less frequent you will need to repot the bonsai. An older tree may need to be repotted about every three to five years. Bonsai trees do not have to be stick to a schedule when it comes to repotting. Instead, inspect the roots. If the roots start to form a circle around the root system, you can either prune the roots or you can keep the roots and put the bonsai plant in a bigger container.

It’s best to repot your bonsai tree in the late winter when your plant is dormant. Because transplanting can cause a lot of stress to your bonsai, choosing to perform this task when they are dormant will not cause as much shock.

If you want to make a bonsai tree grow faster, you can plant your tree in a bigger pot. With more room for soil, the bonsai can extend its roots and store more nutrients. It’s important to add fresh soil when you repot your bonsai. The soil in its existing container most likely has a lot of build-up of salts and minerals. Fresh soil will rebalance a bonsai’s pH level and provide optimal growth conditions.

7. Health Is Key

Like their full-size counterparts, bonsai trees are susceptible to pests and diseases. If a bonsai tree’s health begins to decline, it becomes prone to damage to its root system.

If you’re growing your bonsai tree outside, it can also be exposed to many insects and pests. Some common pests for bonsai trees include aphids, beetles, spiders, mites, caterpillars, thrips, and snails.

Pests and diseases can be diagnosed through consistent observation. Discolored leaves, deformed limbs, or new substances found on or around the bonsai are all indicators of a health concern. Some alarming signs of an unhealthy bonsai include:

• Leaves turning yellow
• Leaves turning brown
• Dying leaves
• Sticky leaves (Why Does My Bonsai Tree Have Sticky Leaves?)
• Tree looking weak
• White powder around the tree
• Flies around the tree
• White spots on the tree

If you suspect that your tree has been exposed to pests or a disease, you must diagnose and treat it immediately. Speak to other bonsai gardeners either locally or on an online forum. Once you’ve identified the problem, you can find many pest or disease treatments at your local nursery or online stores. 

It’s important to keep your bonsai tree healthy and properly maintained because that reduces the risk of infection. A healthy tree will grow faster.    

Final Thoughts

The art of bonsai is a lifelong commitment that requires a lot of patience. While bonsai trees can live over generations, they take a long time to grow. There are several ways to shed years in growth time. Keep your bonsai tree healthy and fed. If your bonsai tree is ever sick, your focus should be on making it healthy again. Proper pruning and exposure to necessary nutrients will encourage your tree to grow to its maximum potential.

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