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.

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.

Maple Progression

April 10, 2015May 22, 2016Bonsaiplace 1 Comment

This Acer stands 35 cm tall and is still very much in training. This photo was taken in May 2013 and it shows the tree in full Autumn splendor.

Soon after this photo was taken the tree lost the last of its leaves and the branch structure can clearly be seen here.

The branch on the right is too straight, but the tree does need a bit of width. The smaller branch above it still needs to grow to fill that gap. The three branches going almost straight up is also disturbing on the eye. What cannot be seen here is that the tree has very few back branches which means very little depth.

Skip seven months and this photo is from the other side. A back branch has now been pulled down by the guy wire and the second branch on the left (previous photo right) is filling in nicely.

This photo was taken in December 2014.

There is now more width to the tree, but the vertical branches making up the apex have not been sorted yet. That is the next phase of development, a repot come spring and that will be in a smaller, more appropriate pot.