Re-potting Bonsai

Repotting ones bonsai is crucial for achieving continual successful growth, year after year. Bonsai roots need to be trimmed to prevent the tree from becoming pot-bound. A pot-bound bonsai leads to nutrient deprivation and eventually causes ones tree to starve to death. Re-potting ones bonsai will not stunt its growth but rather provides it with new nutrients, which allow the tree to grow and become healthy.

The organic matter in soil continually breaks down over time, causing the soil to become compacted. Compacted soil means that the soil will lack aeration and loses the ability to drain excess water. This leads to ill-health in bonsai, which is why re-potting, escpecially in organic soil mixes, is so necessary.

There is no definite schedule which one can follow on how often to repot a bonsai. Each individual tree has its own needs. Most articles one reads, will say  to re-pot about every 2 years, but personally I do not agree.  The most full-proof way of telling when to re-pot a bonsai is by lifting it out of its pot/container- if the roots are still contained within the soil and are not yet visible around the edges of the soil line, then it is not quite time to re-pot yet.

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The best time of year to re-pot a bonsai is early spring. The reason for this is that the tree is still coming out of its winter dormancy, thus reducing the potentially damaging effects of root-ball trimming. It also allows for the tree to grow new roots for sustaining itself right at the beginning of the growing season, therefore decreasing the chances of any damaging effects that may have been caused during this process.

"What root-ball trimming?" one may ask. Well in the opening paragraph I mentioned that roots need to be trimmed to prevent a bonsai from becoming pot-bound- this is the most important part of re-potting. Remove the tree from its previous pot and gently remove all the soil, leaving just the roots exposed.  NEVER REMOVE MORE THAN 70% OF THE TREES ROOT SYSTEM. You should ALWAYS have 30% of the original root system remaining to ensure the survival of your tree.

If you are worried that you have removed too much of the root system, remove some of the trees foliage, this will help it to cope. Another thing to bare in mind is that the total surface area of those delicate little roots, far exceeds that of the larger roots, thus increasing nutrient absorption, making them more important than the thicker, longer roots. When re-potting always keep the trees roots moist- if they dry out, they will die. Therefore the faster you can complete this process the better. So try to prepare your potting soil mix beforehand and have your selected pot ready ...

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The best way to ensure a successfull repotting is by placing a mound of your selected soil medium in the centre of the pot, this helps ensure that  there is not a large empty space under the base of the tree. Open up the now-trimmed roots and spread them out around the pot. Work the soil in between all the roots, gently but thoroughly. Upon completion, soak the entire bonsai- pot-and-all in a basin that is deeper than the height of the pot. When all the excess air has stopped bubbling to the surface, remove the tree and place it in your en.

Planting Demonstration at the Companys Garden

From left to right: Dillon Race, Jonathan Cohen and myself.


This photograph was taken by our groups leader, Paul Parker, at a bonsai exhibition held at the Company's Garden in Cape Town where my fellow bonsai-men and I did a Pomegranate forest planting demonstration.

Pot Selection and Preparation

Pot Selection

It seems logical that one would assume that the bonsai tree itself creates the entire composition of what constitutes a finished bonsai, but in actual fact the pot is just as important! For a tree to reach its full potential a harmony between the pot and tree must be achieved. Finding the perfect pot is possibly one of the most difficult tasks a bonsai enthusiast can be faced with. The pot that you eventually choose to make your bonsais' permanent home will ultimately be one that reflects your personal taste. The four main things to look at when choosing a pot are the pots dimensions, shape, texture and colour.

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Dimensions 

-The pots depth should be equal to the diameter of the trunk at the base of the tree.                                                                              

-For oval and rectangular pots, the pots length should be 2/3 of the height of the tree.                                                            

-For round pots, the pots diameter should be 1/3 of the height of the tree.                                                                                          

-A shallower, wider pot can help compensate for trees with extra-wide canopies.                                                                                                                                                                      

-These guidelines are based purely on aesthetics and are not suitable for all species!

Pot shape

-To choose the correct pot shape, one must first decide whether the tree is masculine or feminine.

-More often than not, a tree will be a combination of both masculinity and femininity- but one will always be more dominant than the other.

-Masculine trees should be potted in rectangular pots and feminine trees should be potted in oval pots.

Texture

-Choosing a pot with the correct texture, once again, comes down to whether the tree is masculine or feminine.

-A feminine tree will suit a smooth clay finish, whereas the wildness of a masculine tree is brought out by the roughness of a pot.

Colour

-The colour of the pot is used to pronouce certain features of a tree, be it the bark, foliage, or even the fruits/flowers.

-This can be created by either using colour harmonies or by contrasting colours.

Choosing a suitable pot is a difficult process but it is one that can be mastered over-time. It will always come down to an individuals personal taste and no-one can ever tell you that you have made a bad decision as there is no right or wrong.

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Pot Preparation 

Preparation of your selected pot is a much easier process, thankfully. Simply wash out and dry the pot. Place gauze tape over the drainage holes and cover the bottom of the pot with a thin layer of small 2/3mm stone to aid in drainage.

10 Year Old Wild Olive For Sale

Selling my 10 year old Windswept, Wild Olive.

Here is the link to the Gumtree Advertisement

Bonsai Potting Mixture

Bonsai are grown in pots and therefore have a limited space from which to aquire water and nutrients. Unlike plants which grow in nature or in your garden, your bonsais' root system cannot obtain water, nutrients or air beyond its containers walls.

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When selecting a suitable medium for potting bonsai, there are certain criteria that your mix will need to meet. It must be able to retain water and nutrients for your tree to grow and provide adequate airspace for drainage to prevent water-logging. To achieve this balance, one must find the correct mixing ratio of organic and inorganic matter.

'Good' water retention is important because it will keep the soil moist between waterings. This is crucial because the trees roots require moisture to survive. Too much water retention however, can become extremely damaging to the tree.

For this reason good drainage is necessary. Your potting mixture must allow for all excess water to drain from the pot immediately. Soils which lack good drainage become too water-rententive and therefore lack aeration and tend to cause a build up of salts.  Water-logging can also lead to root-rot.

It is also critical to the survival of the root system that it has access to sufficient amounts of oxygen. For this reason aeration in the soil is necessary. To allow for aeration there must be enough space between particles to allow for tiny air-pockets.

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Although all trees require free-draining, water-retentive soils, different species have different water and nutrient requirements. Therefore there is no 'one-fits-all' soil composition, which makes describing the perfect soil mix for your specific bonsai an impossible task.

A good example of this is that Junipers and Pines require significantly less water than most other species and therefore require a less water-retaining soil mix. Alternatively, flowering and fruit-bearing species require a lot more water and should be potted in a higher water-retaining mix.

Adding course, inorganic matter, is an efficient and suitable method of achieving better drainage for those Junipers and Pines. Increasing the amount of organic matter in the mixture allows for a more water-retentive composition but becomes risky as it can lead to water-logging.

Every individual bonsai artist will have to discover which mixture works best for each of their individual species. This is why making your own potting mix becomes so much more economical and beneficial.

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Try to find someone in your local area who is also a bonsai enthusiast and find the potting mixture that works best for them. Alternatively, contact a bonsai nursery and find out what potting medium they would recommend you use, in your region.

Kei Apple

After

This is a new idea that I'm trying. This Kei Apple is a very unique specimen and I have an equally unique end-product in mind, although there is still much work to be done. 

Before

Will keep you updated on my progress. 

Bonsai Size Classification

One of the many great aspects of learning about bonsai is knowing all the technical terms that go with it. Being able to classify your bonsai in regards to its size and by using the correct terms is a great way of showing off your knowledge!

Bonsai height is generally measured from the base soil level up to the apex of the tree.

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Here is a brief guide:

• Keishi Bonsai can be up to 2.5 cm in height. (Miniature)
• Shito Bonsai can be up to 7.5 cm in height. (Very small)
• Mame Bonsai can be up to 15 cm in height. (Small)
• Shohin Bonsai can be up to 20 cm in height. (Medium)
• Kifu Sho Bonsai can be up to 40 cm in height. (Medium-large)
• Chu Bonsai can be up to 60 cm in height. (Large)
• Dai Bonsai can be up to 100 cm in height. (Very large)

Crassula Forest Planting

The theme of this forest is windswept. It features 5 Crassula trees.

The centre or 'father' tree was placed on a mound in the centre of the planting. He is one of few fully intact trees, showing that he was able to adapt to the forests conditions. The other two unbroken trees are adolescents which were able to receive enough shelter from the father tree to stay intact although they still show signs of strain due to the windy conditions.

On the left is a large stocky trunk which has been blown over. This particular Crassulas trunk was too sturdy to bend under the windy conditions so instead it was blown over. Its fall was broken by a large boulder allowing some of the trees roots to remain intact, therefore prolonging its life.

On the right hand side is a broken Crassula stump. This stump, being positioned on the edge of the forest received the full force of the wind and was unfortunately not strong enough to withstand it and therefore broke under the strain.

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To achieve a successful forest one must envision a story and use that story as a theme to develop the forest. Using themes to design forests helps to achieve an authentic look which is crucial to creating a champion forest. Best of luck to all those who wish to create a forest! :) 

Kei Apple

My Kei Apple, planted root over rock.

Planting Demonstration

My fellow bonsai-men and I created a wonderful forest planting at a bonsai exhibition. The planting was done as a demonstration for the public, in The Company's Garden in Cape Town on the 3rd of September 2011.

Our planting consisted of 10 multi-trunk Pomegranate (Punica Granatum) trees. The forest was planted in soil which was held together by mutton cloth, onto a large slab of black natural rock which was found about 2 years ago. 

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The forest will take between 1-3 weeks to settle in and for the roots to take hold of the soil. The mutton cloth will take about 6-8 months to decompose leaving just the soil and rock. Moss has been planted on the surface which will hopefully grow successfully, adding some character to the planting. 

Creating the forest was good fun and a great learning experience, receiving advice from top bonsai artist, Rudi Adam. Hopefully all those who got to watch the process were inspired and enjoyed it as much as my fellow planters and I did. 

* Photos will be added shortly once the forest has settled.