by Terry Erasmus January 30, 2018 4 Comments

Introduction

I purchased this tree, a small rooted cutting in a bag, from the late Rudi Adam around 2006 and continue to develop it till today. I'd like to share with you the process that I used to achieve the tree it has become. In order to do this I have decided to split up its development into the three basic stages I take most of my bonsai trees through:

  1. Field growing
  2. Development
  3. Refinement

Until recently I believed this tree was a Chinese elm, the species often used in the past for street planting. However, I was working on it at a show a few years ago and Freddie Bisschoff, well respected for his top class elms, advised me that it was in fact an English elm.

Stage 1 - Field Growing

It is an irrefutable fact that if you want to fatten the trunk of a tree which you intend using to create a bonsai from, field growing is the best method. Although not all trees need to have fat trunks with dramatic taper, you may wish to develop a more feminine tree for example, however I have yet to come across a tree which I have grown which in my opinion did not benefit from at least a few years in the ground. Bear in mind also that once you have potted your tree into a small bonsai pot, you will not see any significant trunk thickening taking place from that point onward. I am sure you have heard it before, but let me re-iterate; don't be in too much of a rush to get your trees into a bonsai container.

I have written about the subject of field growing in some detail in previous blog posts, so if you are not sure what I am referring to then please do take a moment to familiarize yourself with the concept.

Raised growing beds for bonsai

Image caption. Raised growing beds made from brick. Raised beds are far easier to work in than flat on the ground. I had a special mix of media made up to fill them with and the growth of the trees I developed in them was very satisfactory.

In 2010 I built raised, brick growing beds in my back garden and it was in these growing beds that this tree saw the final years of its time in the ground. {Since then I have removed all the trees, moved them to a nearby farm and have built more benches where these raised beds were}

Chinese elm field growing

Image caption. This is the earliest image I have of this tree unfortunately. In 2010 you can see that the trunk is already fairly substantial having already been developed for a few years from the original rooted cutting.

Before this {and another elm, a variegated leaf variety} I had never developed an elm in the field before and it always helps to know the characteristics of the species when doing this work. For example it would be beneficial to know just how thick you can allow a sacrifice branch to develop before the resulting scar will not heal over properly anymore. Its also good to know just how drastically you can cut the roots and when the best time is to do such major root pruning. There really is no substitute for personal experience and the best advice I can give you is that you should try it yourself and in the process your confidence will grow.

Potted Chinese elm

Image caption. The tree in a pot, 2012.

After a couple more years in the ground I finally decided to remove it from the growing beds and put it into a container. Knowing when the best time is to do this, and I don't mean the month of the year, comes down to experience. However to write in a very general fashion I'd say you need to consider the following and based on your answers you may or may not decide to move the tree to a pot. You will also note that you are almost exclusively going to consider the trunk only as branches come later, usually also as you remove all branches grown in the field anyway:

  • Is the trunk think enough to achieve the style or mental image of the tree you had in your imagination? Yes, then lift it. No? Keep growing it for a few more years.
  • Is there sufficient taper? You will not be able to correct this easily once potted. If its not enough then use sacrifice branches low down on the trunk or perform a trunk chop and continue to develop the trunk from there.
  • Enough movement? Bending the trunk of a deciduous tree, without causing a lot of scars, is not that easy. Movement is usually created with repeated trunk chops and at each occasion changing the direction the trunk is growing in. It may already be too late to put movement into the trunk, but if you have long and strong sections then I'd recommend further development in the field after a trunk chop.
  • All major scars healed? In my experience, if a scar remains on the tree larger than say the diameter of a broom stick handle and you put it into a pot, you are going to wait a long time for it to heal over. It may never heal over.

Stage 2 - Development

In the first stage, the goal was solely to give us a good foundation for a future bonsai tree. Considerations which were important then were the trunk and the roots. However, in this 2nd stage of the trees life as a bonsai these considerations might change, and in fact they do. Instead of trunk thickening we now consider branch placement. The nebari we achieved in the first stage will now be further developed through various techniques.

Chinese elm bonsai nebari

Image caption. By the time the tree gets to Stage 2 the foundation for a good nebari should be fairly advanced.

The container

Probably the most visual difference between the 1 and 2nd stages is that the tree is no longer grown in the ground or perhaps an over-sized container; the container is now a little closer to the final size the tree will ultimately be refined and possibly exhibited in. 

If you have a suitable ceramic container then use it but if not, then you can make yourself a wooden box. Alternatively, you can use a plastic tub, tray or similar vessel. 

What I'd like to stress about the container for this 2nd stage is not so much the material but the size. It must be smaller than what was used in the 1st stage but it must not be so small as to restrict growth too much. You want controlled growth yes, but as we now need to develop the basic branch structure you will be using certain techniques to achieve this and they require a little more pot volume.

Growing Medium

I have already written much on this topic and you can see previous posts here. However, the main role for the growing medium in this stage will be that it drains of course to avoid root rot issues but also to provide aeration for the roots which you want to develop. Bear in mind that when you dig the tree from the ground you most likely will remove most of the roots and probably all the finer roots, so you need to encourage these to grow back again as soon as possible.

Branch Structure

As your trunk determines the style or possible styles you can consider for the tree this decision has already been made for you to a large extent i.e. the trunk is already shaped in a certain way and changing it now will not be easy and most likely will put you back into stage 1. For my elm I had decided that it would be fairly upright and that I wanted it to appear rather mature, so the bottom branches would need to sag. With these decisions made I could determine roughly where the first branch should be and its angle based on the height of the trunk.

At this early stage it is best to grow as many branches as you can so that you can eliminate them later. I made many mistakes before by removing all the branches which did not fit the visual image I had in mind for the tree right in the beginning, only to find that the tree did not really want to grow some of the branches I had kept. So now I try to keep as many as I can and then remove them later if they start becoming a problem; for instance, starting to create reverse taper or becoming too crowded.

Developing branch structure

Image caption. Your tree will still not look like much but be patient. At this stage much of the initial branch structure work is completed.

Using the technique of sacrifice branches, you will now develop the basic branch structure of the tree. The process involves growing the branches as long as necessary until the jump or transition from the girth of the trunk to that of the branch or branches is pleasing. It’s hard to define what is pleasing but it needs to make horticultural and aesthetic sense. Horticultural; meaning that you cannot expect sufficient sap to be able to support a highly ramified branch if its only pencil thickness. Aesthetic; meaning that a very thin branch growing from a very fat trunk will appear wrong. Finally, don’t rush this step or you will regret it in the future as once you start building ramification should your branch not be thick enough to correct will mean eliminating any ramification developed to that point, so you would have wasted several years.

Top view Chinese elm

Image caption. Don't forget to view your tree from the top as well to ensure you are developing branches in all directions. Its very easy for a tree to become very 2 dimensional otherwise.

When growing sacrifice branches, it is best to eliminate all side growth and focus on directing the auxins (found in the growing tip which lead to branch extension) to a single growing tip. What happens as a result is that this branch becomes very long and in order for it to be supported it must fatten quickly. I am also convinced that when the wind blows it creates small cracks, much like what we do when we wire, as the plant heals these injuries it will also increase the girth.

As soon as the base is thick enough you can cut the branch back. How short you cut it is based on your future outline of the tree. By this I mean that if from the cut you can only afford for the tree to grow another couple centimeters then this will not be sufficient to create ramification in it’s a large tree. Perhaps to generalize very broadly cutting this branch back to a 1/3rd of the total, final length should be ok in most cases. However, the more time you take in creating the basic branch structure the better the overall result, so growing it on, cutting back, growing on, cutting back repeatedly will ultimately create a branch with a lot of interest as the branch changes direction every few centimeters. No herring bones welcome here!

Chinese elm scarring

Image caption. Be careful that you do not take trees from stage 1 through to stage 2 with scars which are too big, they are unlikely to heal easily.

Another benefit of sacrifice branches is that they can be used to help heal over old scars. This is especially the case if the branch is just above the scar. The intensified sap flow required by the branch will result in the callousing over of the scar. However, be careful that you do not expect too much in the way of healing as scars heal better when the tree can grow unrestricted in the ground. Things happen much slower in a container, if they happen at all. Read more about dealing with scars here.

Wiring

It is very important that the angle at which the branch emerges from the trunk be correct. A new shoot will most likely grow rather vertically, but you can correct this with wire, if you do not wait too long. Yes, there are techniques like wedging and others which you can sometimes use to change this angle at a later stage but why not try doing it the easy way and wire it before the wood lignifies (hardens off).

When wiring a branch don’t only wire that it has interesting curves when viewed from the top, it must also have character from the front. Also, if you have a fairly upright trunk like this elm of mine, I cannot have branches which have dramatic curves, visually you will be sending a very conflicting message and of course it will make no horticultural sense at all.

Wiring Chinese elm

Image caption. Aluminium wire is best for deciduous trees. Make sure you wire in curves front to back and up and down.

Don’t worry too much about wire bite now, in fact I think a little wire bite can be a good thing as it can add some interest to the branch, so long as it does not get too bad. With species such as this elm which heal easily, wire bite even if rather severe can always be smoothed with a grafting knife and sealed and in a season or two you wont even notice it. However on something like a Japanese maple or even an olive, it may take many years to heal properly indeed. Removing the wire too early from a branch, before it has had sufficient time to set in position, will mean you will have to reapply the wire, wasting time and money.

Chinese elm complete

Image caption. Four years after potting, this elm can now move into the 3rd and final stage of development, refinement.

Fertilizing

I should also mention something about fertilizing when discussing stage 2 as encouraging rampant growth with high nitrogen feeds will result in very long internodal distances. This refers to the distance between leaves along a branch, where you will also find the dormant buds. Normally, this extension is straight and without any taper. You might be able to create movement with wire however if one day you need to cut back or encourage budding back along this area, the branch can only bud back to where there is a dormant bud. Shop from our extensive range of popular fertilizers and read their reviews here.

In the next post I will continue with the 3rd stage, Refinement.





Terry Erasmus
Terry Erasmus

Author


4 Responses

Brian Kalshoven
Brian Kalshoven

February 10, 2018

I’m following this with interest, as it condenses many years of development into a short space of time. So far, on my trees, I’m not doing much wrong, yippee! Looking forward to the refinement, as I’m constantlydoing that with a number of my older, established trees. The longer I follow this hobby, the longer I realise that every tree, even the oldest, most developed subjects are always going to be a “work in progress”, and that’s what makes it so great. Thanks, Terry

Forrie Miller
Forrie Miller

February 09, 2018

This is a fine site and a terrific article. I am a Kiwi whose oldest bonsai dates to 1981 and survives as a testament to my many errors. I happened on the website when motorcycling through South Africa last year, and I now follow it with interest.

Terry Erasmus
Terry Erasmus

January 31, 2018

Thank you Gora for your very kind words! Just when I think people could not be bothered with what I ramble on about, I get a comment such as yours. Seeing as you ask so nicely I will certainly do my best to keep it up!

Hassim Gora Khaki
Hassim Gora Khaki

January 31, 2018

Thank u Terry for your hands on approach to teaching us novices on how to develop trees for bonsai. I personally have benefitted greatly from your blogs. My trees are the better for it. Such valuable and simple to understand information as provided by you is not often shared by our bonsai masters and it is most valuable for the novice who wants to develop his own prised bonsai. Keep it up buddy. Really appreciate the sterling job you are doing to promote bonsai.

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