This Month in the Garden: A Brief Guide to Growing and Caring for Bonsai Trees

A Brief Guide to Growing and Caring for Bonsai Trees 

Bonsai trees can be a beautiful and compact addition to any garden or arboretum, or as a decorative house-plant with a bit of a twist. The origin of the word bonsai is often misunderstood, with the phrase being used as a catch-all for a wide range of miniature trees and flowers. In fact, the cultural origin of bonsai trees is slightly more complicated, and certainly more interesting, than people may at first realize.

The origin of the term “bonsai”

Bonsai is a Japanese phrase, meaning “tray-planting”. Japanese bonsai is itself a re-interpretation of the Chinese “penjing” (or penzai) art form, which followed similar principles. It was in the Chinese empire where these artistically designed trees were thought to have originated, since the Chinese used special techniques to grow their penzai trees in shallow containers. From the 6^th century onwards, Japanese students and diplomats visited the Chinese mainland and brought back many Chinese art forms, ideas and religious souvenirs. Slowly, over subsequent centuries, the concept of tray planting began to be incorporated into Japanese culture. Bonsai is the Japanese translation of the Chinese “penzai” art form. The bonsai art form was fused with Zen Buddhism, and Buddhist monks passed on bonsai cutting and planting to Japanese political leaders. The growth and maintenance of bonsai trees became more mainstream over subsequent centuries. By the eighteenth century, bonsai show cases and fairs were being held in Kyoto, then Japan’s capital city. In the aftermath of the Great Earthquake of 1923, Omiya Bonsai Village became a home for a multitude of bonsai nurseries in the suburb of Omiya just outside of Tokyo. By the 1930s, a bonsai exhibition had begun to be held annually at the Metropolitan Museum of Art.

Bonsai growth and cultivation:

A Bonsai tree is grown from source material, a plant which the grower may wish to cultivate into Bonsai form. The source material for a Bonsai plant is usually already partially grown; cultivating a Bonsai tree from seeds will take much longer (as much as three years). The more favoured cultivation techniques include:

Cutting – part of a growing plant is cut off and placed in a growing medium, usually a shallow tray (hence the phrase bonsai). The thicker the branch cutting, the more likely it is to grow into a richer bonsai tree. Spring and summer are the best times to cultivate your plant cutting.

Layering – a branch of the tree/plant is encouraged to take root whilst it is still attached to the main body of the plant. After this rooting, the branch is then allowed to grow independently.

Popular styles of Bonsai tree:

Ficus bonsai:The ficus tree belongs to the mulberry family and is the most popular Bonsai species for beginners and growers who are new to the art form. There are hundreds of Ficus species, but the most popular is the Ficus retusa, which is often shaped in an S-shaped trunk. The ficus Bonsai is an indoor plant and cannot cope very well with cold temperatures. If kept outside, it needs to be in temperatures above 15 degrees Celsius. They also need a lot of light in order to grow. They should be watered regularly and re-potted every spring in basic soil.

Juniper

Juniper bonsai: The juniper tree exists in the cypress family of trees, and there are between 50 and 70 varieties. Juniper bonsai are coniferous (evergreen) which are popular for Bonsai purposes. Unlike ficus Bonsai, junipers are well suited to growing outside. They will also change colour during the winter months as part of a defense against frost and the more extreme temperatures. It’s important that you don’t water juniper bonsai too much, as their roots don’t thrive in excessively wet soil.

Japanese Maple

Japanese Maple Bonsai: The green Japanese maple bonsai is well-known for the orange, yellow and red autumn colours. It is best grown in sunny, airy conditions, and should be placed in light shade. It can withstand cold temperatures, but should not be left in hard, frosty conditions. Japanese maple Bonsai need to be watered daily.

Chinese Elm

Chinese Elm Bonsai: The Chinese elm is native to south east Asia. Whilst the Chinese elm is also a mighty tree in its own right, its small leaves also make it a good choice for Bonsai potting. The Chinese Elm bonsai grows well both in sunlight and moderate shade. Chinese elm can endure being raised and grown in cold temperatures, but this may depend on which part of the world it was originally grown in. Chinese Elm need to be watered generously.

What soil do Bonsai trees need?

If you are unfamiliar with caring for a bonsai, one of the first and most important factors you will need to consider is the type of soil in which to place it. Bonsai will not flower and prosper if they are not placed in the right soil, as soil is vital for supplying your trees with the right nutrients, aeration and water retention. Bonsai trees placed in “traditional” soil are unlikely to last long; hence, it is important to understand how to create the right soil conditions for your tree. After all, Bonsai trees are arguably a piece of art, and their unique structure depends on them being well-watered and well-maintained. There are a number of factors, which we have already touched on above, which are essential for your Bonsai tree to thrive.

Water retention: Water retention is essential for Bonsai soil, as the soil structure needs to be able to hold moisture in between watering.

Aeration: The particles of Bonsai soil need to allow for oxygen to pass through the soil, ensuring that sufficient oxygen is transported to the roots of the Bonsai tree.

Drainage: It may seem confusing, but it’s also important to remember that drainage is also important in choosing and preparing the right Bonsai soil. Excess water must be able to drain away from the Bonsai’s roots. This means that heavily compacted soil isn’t usually suitable for your Bonsai tree.

The composition of Bonsai soil: There’s no single way to arrange your Bonsai soil to create the conditions outlined above, but there are certain soil components which can increase your Bonsai tree’s growth and health. A Bonsai soil with the optimum conditions to allow for water retention, aeration and drainage will usually contain a mixture of organic and inorganic soil components.

Organic components:

The organic components of good bonsai soil include any of the following.

Conifer bark–Conifer bark is a good soil conditioner, which allows for both good drainage and the retention of water.

Peat moss–this helps to retain water, and bonds the different components of your Bonsai soil together. It should be used sparingly, as it can prevent sufficient drainage if not used correctly.

Potting soil–this adds bulk to the Bonsai soil, and helps to retain water. This component should also be used in small quantities, as too much could prevent drainage.

Inorganic components- Inorganic soil components do not break down and are more likely to provide aeration and necessary drainage for your Bonsai tree. This means that inorganic components are great for helping your Bonsai’s root growth.

Akadama Clay–Akadama is hard-baked Japanese clay which is specifically produced for the purpose of growing Bonsai trees. It’s worth noting that Akadama clay will break down, but only after two years or so. This works out nicely, as Akadama clay can be quite expensive!

Lava rock–this can help with water retention, and further re-enforces the soil structure for your bonsai tree, as roots can’t grow into it.

Pumice–a soft volcanic product which can absorb water and nutrients, once again helping water retention.

Fine gravel–Gravel can help with drainage and aeration for your Bonsai. It’s best placed at the bottom of the plant pot.

It’s worth noting that different soil mixtures will be needed for different types of bonsai. There are different soil compositions for deciduous and coniferous Bonsai trees (for example deciduous Bonsai trees will require a higher ratio of akadama clay). Since Bonsai trees are a whole family of trees, there’s no uniform soil composition for every size and shape. In the end, Bonsai trees depend most of all on their owners using the most care and craftsmanship in tending to them.

Thanks to Kaizen Bonsai for providing this valuable reference. After more than 20 years in the bonsai business, they continue to educate the public on the care and maintenance of these beautiful trees. For more on bonsai, be sure to visit their informative website at Kaizen Bonsai.

~As Always...Happy Gardening!~