Horticultural Processes and Bonsai: Photosynthesis

July 17, 2021July 17, 2021Bonsaiplace 2 Comments

It is a well known fact that horticultural knowledge and skills should be on par with the creative side of Bonsai cultivation as a horticulturally neglected tree will never reach its full potential as a Bonsai. It is therefore important that some basic horticultural knowledge and skills are mastered early on the journey towards Bonsai mastery.

This series of articles has it as goal to highlight a few processes in horticultural science and linking this knowledge to Bonsai creation and maintenance. We will start off with the most important one and that is Photosynthesis. Others will follow in subsequent articles.

Photosynthesis

A bit of knowledge relating to cell science will help here. In plant cells, usually where there is a green colour, you will find cell organelles called chloroplasts. Inside these there is chlorophyll, a colour pigment, and this one is attributed to the green colour in plants. This is where photosynthesis takes place. Photosynthesis is the process through which plants use raw material to produce food. The raw materials are carbon dioxide and water and with the aid of energy from the sun, food is produced and oxygen is made as a by-product of this process.

What does this mean for Bonsai? The most important part here is the exposure to light. Without this natural light source not enough energy will be available for this process. The second part is that there should be enough chloroplasts available for this process to take place. The significance of this comes in at pruning time. It needs to be at the right time as there should be enough energy / food stored to carry the tree through the period with either no leaves or very few leaves, as at this time food production will be limited. This is crucial for evergreens as the food storage or energy storage side of these plants are not as well developed as what it is for deciduous plants. See the process of transpiration in another article as it plays a role with this as well.

In summary:

Your tree should have adequate light for food production.
Your tree should have adequate water for food production. Water plays a role in other processes as well which makes watering a crucial task for healthy Bonsai growing. See transpiration as an example.
Adequate ventilation is necessary to allow atmospheric carbon dioxide to get to your tree. This is usually not a problem in the outdoors, but something to think about when you cover trees with plastic to increase heat and humidity for growth purposes or other climatic defensive reasons.
Pruning and defoliating. Time this right. Never defoliate an evergreen completely unless it is just a branch or two for the purpose of creating deadwood / Jin.
When positioning branches and foliage pads, make sure that top branches do not cover lower branches too much.

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Subscribing will help as you will get the updates for the other processes covered in this series. That includes transpiration, respiration, growth, secondary thickening, tropisms and the importance of hormones in all of this.

Let there be Light – Bonsai light requirements.

June 6, 2020Bonsaiplace 1 Comment

Photosyntheses — the process through which plants use energy from the sun, water from the soil and carbon dioxide from the air, to produce food for itself and then also oxygen. From this, we see that it is really important to get the light requirements of your Bonsai trees right.

Phototropism – the phenomenon where plants grow towards light. This is mainly caused by hormone stimulation that forces plants to grow towards the light source.

Too little light can cause issues and then you also have the other side of this continuum, the heat caused by direct sunlight, that can also cause harm.

Leaf scorch can also be caused by dry winds.

Let’s look at situations where the tree is in the shade too much. This could cause a deficiency in energy production, unless it is a plant adapted to grow in shade. Shady conditions can also cause leaves to grow larger and then also for branches and especially new growth to become spindly with very long internodes. Both of these growth patterns are not very good things for Bonsai where you need smaller leaf sizes and also more compact growth.

A more open aspect with no large structures providing shade.

Another light consideration is where you place your Bonsai trees in relation to the light source, i.e. the sun. Plants tend to grow towards the sun and if placed against a wall, it could be that the tree will grow away from the wall. It is also possible that you will have very little growth on the shady or wall side of the tree. The solution to this problem is to turn your trees often. Some of my trees, that are on stands / monkey posts with no wall near them, quickly show me that they need to be turned as well. It could be slight yellowing of the leaves or needles on the southern side (I am in the Southern Hemisphere) or denser growth on the sunnier side than the shadier side.

A Wall and even an open, but solid structure will influence growth patterns.

What is the most important here is to know more about the natural habitat of your trees. If it is a natural shade lover, you could get the opposite to what is described in the previous paragraph. Also look out for burn or scorching of these shade lovers on the sunny side.

Think about the placement of your trees. Study the different microclimates that can be caused by high walls or fences as well as trees and other plants. The construction of your display stands and where these are placed in your garden are all very important aspects of your Bonsai cultivation. When it comes to the regular turning of trees, I have a fixed day twice per month and I turn the tree through ninety degrees, always in the same direction (for me that is clock-wise). Sometimes I will keep it longer in a specific position due to the fact that there could be an undeveloped branch that needs the light source for longer to get its development up to speed.

On the left is a Pine with some yellowing on one side. On the right uneven growth pattern due to being too close to a wall.

You also need to think about the light requirements when it comes to specific maintenance tasks. After root pruning or repotting it is also best to keep your tree away from direct sunlight for a few days to a couple of weeks. The opposite when you get into the different grades of defoliation.

One of the reasons for defoliation, whether it is fully or partial, is to stimulate back budding and for this, more light is needed.

If you are heavily invested in Maples as Bonsai, it will be worth your efforts if you look at different light requirements of Maples as it can influence stunning Autumn colours and even new colours in Spring. That is a topic for another day.

Same tree at different times of the year. Temperature plays a big part here, but so is light exposure.

It is not complex, but certainly something to think about when you position your trees and every time when maintenance tasks are undertaken.

Newbie Bonsai Help.

February 25, 2018February 25, 2018Bonsaiplace 2 Comments

It is very common to see a photo of a seedling or small nursery stock on social media with the following comment: “I am new to Bonsai, please help with advice”. Where to start? What the follows is a number of people writing one liners or a bit more with a genuine interest to help.

I have been demonstrating and teaching Bonsai now for many years and am following what I think is a logical series of steps to enable the new Bonsai enthusiast to work towards a specific goal. It is almost paint by numbers, but in the absence of knowledge and skills, it is the best way to get the basics across in a short period of time. Here are the steps:

Unearth the topsoil to look at surface roots.
Determine the front of the tree.
Decide on a natural flow of the trunk dependent on the style envisaged.
Decide which branches / side shoots to keep.
Remove excess branches and foliage.
Some of these can be selected for deadwood (jin).
Create Jin.
Wire main trunk if required.
Bend trunk to desired shape.
Wire branches into position.
Clean hanging foliage up.

Each of these steps require a lot of knowledge to get to the end result. This is part of the conversation as the design unfolds. Small nursery material can take up to three hours to style with a new enthusiast in a workshop situation. The hands-on work takes only about thirty minutes to complete, but the explanations and answering of questions, in my mind the most important part, takes up a lot of time.

This Juniper is nursery stock and is 20cm high from the top of the soil. It has been standing around here for a year or so and received very little attention.

The first step is to scrape some of the soil away to see if there are any prominent, larger roots that can help to make a decision about the front / viewing side of the tree. In this case it only contained a whole lot of fine fibrous roots.

It is therefore now up to the trunk line to give an indication of what could be a possible front. For newcomers, we usually look for good movement and flow.

Once the best angle is determined to show things like flow and movement as well as taper or interesting features, it is marked and excess branches and foliage can be removed to reveal the trunk line. The conversation at this stage will include things like removing branches growing from the same height, branches on inside curves and crossing branches.

Some of the branches are identified as possible deadwood branches and these are kept a bit longer. Bark is then removed.

All of these steps have cleared the path for the trunk to be wired. Just the basic of wiring is explained and demonstrated at this stage as this skill is seen as a bit more advanced for a newbie. I think it is important to allow the person to start on their wiring pathway as it is an integral part of Bonsai design. As said, we stick to the basics at this point. It is more important to talk about design and flow at this point.

The branches can now be wired.

The next step is to place the branches in position while a conversation about safe bending takes place. Overall tree health is emphasized at all times. Once the placement is done, excess foliage, especially those growing downwards or upwards is removed. The concept of foliage pads is also touched upon. I find it is important to at this stage point things out like depth (back branches) and negative space. These are all explored ta more advanced workshops.

The last part of the workshop is focused on future growth, the role on foliage in feeding the plant (photosynthesis) and then the very important aftercare of the tree. Protection of small buds and the removal of older foliage as the tree buds over the next few months is discussed as well as feeding requirements and protection over the next month or so.

Potting, root management, carving, severe bending and more advanced wiring techniques are all part of more advanced techniques to be covered at advanced workshops.

Shorter days, colorful leaves.

April 26, 2015April 25, 2019Bonsaiplace 2 Comments

For us in the Southern hemisphere the leaves of our deciduous Bonsai trees are starting to change color and they will soon be on the ground. In the Northern hemisphere Spring growth is to be seen everywhere and I have noticed a proliferation of photos indicating just that on Social Media. The difference is that the daylight hours are getting less in the South and the opposite is happening in the North. Suffice to say then that it must be the availability and intensity of light that triggers these phenomena. Today I would like to explore the color changes in leaves during Autumn.

We know that there is a pigment in leaves called chlorophyll. It is the site where photosynthesis takes place in leaves. This is the process where water and carbon dioxide gas with the aid of light energy is converted into sugars for plants to use as food or to be stored.

As the days (light) get shorter, there is not enough light energy for photosynthesis to take place at optimum levels. The trees must rest and basically shut down and the only food available to get through winter, is what is stored. As this progresses, chlorophyll disappears from the leaves and the bright green fades away. Chlorophyll is not the only color pigment in leaves. As the green fades, the other color pigments become visible. These are the yellows and orange colors (carotenoids). In some trees, like maples, the glucose produced during photosynthesis gets trapped in the leaves and the sunlight causes the leaves to turn this molecule into a red color. It is known that the cooler temperatures have a role to play in this. There are other pigments present as well. Red anthocyanin pigments can also be produced during this time.

Currently, my trees, and especially the Maples, are not showing the bright red colors yet. This is late for this time of year. Our night time temperatures have not dropped sufficiently for this to happen. Other climatic factors play a role as well. What is needed for all the splendor of autumn to show in our Bonsai trees is a warm, wet Spring, followed by a Summer with average temperatures and an average rainfall as well as an Autumn with many sunny days and relatively cold nights. There is nothing we can do about any of these except for controlling water, but it might be possible to shift trees in one’s garden during Summer and Autumn to make use of micro-climates caused by other plants and the layout of your garden.

Scientific knowledge supports Bonsai cultivation

April 11, 2015May 22, 2016Bonsaiplace 2 Comments

The old debate of whether Bonsai is Art or Horticulture is actually a non-event as we all by now know that a dead tree cannot be designed as a Bonsai and be admired as a living sculpture. We need both. The tree must be kept alive and sculpted to enable the Bonsai within to be shown.

I am in the process of re-reading a lot of my quite sizable Bonsai library. The majority of these books and magazines focus on the Art side of Bonsai cultivation. It is rare to find a good solid article or chapter in a book, dedicated to the Horticulture involved in Bonsai development. A quick search on the Internet shows more of the same. There is a bit more to be found on the Internet, but a lot of this is not necessarily linked to Bonsai specifically. A few examples are of importance here.

The first to mention is the practice of defoliation. When we remove the leaves from a tree, we drastically reduce the level of transpiration (loss of water through leaves), which is an important process supporting the flow of water through a plant. Partial defoliation obviously does the same, but just less. Then there is the practice of leave cutting. This will reduce the surface area of the leaves, which in turn will also have a reduced transpiration level as an outcome. Photosynthesis levels will also drop. There are very good reasons why we do this in the cultivation of Bonsai, but it is a process rarely seen in the cultivation of other plants.

Another of our Bonsai specific activities is the process of deadwood carving or carving in general. Deadwood is dead and nothing much needs to be taken into consideration except for aesthetic principles. When we carve into living wood, things change a bit. Tree tissues are laid down in layers. On the outside we have bark and under this we have the phloem, the tissue that conduct the nutrients produced in the leaves through photosynthesis. The next layer is the cambium. This tissue is responsible for the secondary growth in stems as well as roots. The next layer is the xylem. This tissue transports water from the roots to the leaves. Then we get to the lignin. These are dead cells and make up what we refer to as “wood”. This is the stuff we carve. To get to the lignin, we have to go through the living layers. This needs to be done carefully as we are interfering with some very important processes when we start carving. Not only do we interrupt the flow of nutrients and water, we directly impact on growth. This works well for us as well, as the cambium layer is the one that will help with the healing on the edges of the carving.

My advice is for Bonsai enthusiasts to read and learn about the science behind our activities as well. Not only will this knowledge help to keep more trees alive, it will help us understand the design process and principles better as well.