Category Archives: Fundamentals of Bonsai

Emergency Repot

I recently watched a Bonsai Mirai video about post collection care with world renowned collector Randy Knight. He spoke frequently about his sawdust bed that he uses to heel in “danger trees.” I got the opportunity to try that myself as I came home to what I’m pretty sure was a great lizard chase by my dogs…

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Randy discusses that he uses coarse sawdust, not small particles. I happened to have a friend that uses a lathe and has been giving me black trash bags full of sawdust for awhile now.
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A couple of tips when using sawdust:

  • Make sure to wet it REALLY well. The first time you soak sawdust it absorbs a ton of water and has a hard time getting everywhere, so make sure to be liberal with the water you’re using.
  • Pack the sawdust in good and chopstick or poke around to get the sawdust into whatever root system is there.
  • Layer several inches of sawdust on top of what would be the rootball. This helps to keep any major fluctuations in water or temperature from the rootball.

Here are photos of me digging down and checking the moisture after watering for awhile.

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Packing in the sawdust for a final time.
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After packing and before adding another bag on top.
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After adding and wetting the top layer of sawdust.

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After securing the tree in, I went to further inspect the damage.
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I pulled out portions of the leftover root system to see how the roots were doing before the wild lizard chase. I was mostly pleased with what I saw.
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Plenty of capillary roots growing. Randy also mentioned that new roots almost never grow in the leftover field soil, but in the pumice immediately around the field soil.
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While I had to experience this sad destruction of my collected California Juniper, I’m glad I was able to see that I was having success with what I was doing. Hopefully I don’t have another casualty on my hands.

Fundamentals of Bonsai – Pruning

There are hundreds of questions on bonsai forums, at clubs, and across the globe about pruning. What to prune, when to prune, why we prune, which species can I prune now, how often do I prune, etc. I want to help clarify these questions.

 

I’ll start with explaining why we prune. There are 3 main reasons to prune:
  • Cleaning
  • Controlling Growth
  • Improving Structure
     We clean to improve airflow and allow sunlight to penetrate into the interior and lower branches. This is also a precursory action to wiring and styling the tree. Trying to wire a tree without cleaning it first can be miserable, especially when doing it on a needle juniper.  Cleaning consists pruning off weak interior growth with little to no ramification and  clearing any foliage in the crotches between the trunks and branches. This includes leggy branches that are not developing in the desired direction.
     Pruning is the way we control growth on our trees. This is how we tell the tree to direct more resources towards a specific branch or section of the tree. This helps to keep your branches a specific length or thickness and give them directional movement to draw interest. This is also the technique we use to gain width in certain branches and keep others from thickening too much. I will go into more detail later on how to do that.
Structural pruning is the way we improve taper, inverse swelling (taper), direct the line of the trunk and branching, and remove flawed or unnecessary branches. Being able to prune effectively is the foundation of successful bonsai practice and design.

 

Before we go pruning anything we need to step back and observe a few things about the tree we’re about to prune. We need to identify:
  1. What species is the tree?
  2. What is the tree’s current health?
  3. Did you repot the tree within the last few months?
  4. Why am I pruning?
  5. Is the ______(tree, branch, etc.) that I’m about to prune in refinement or development?
  6. What season are we in?
  7. What is the effect on the tree’s energy and health if we prune now?
1. Some species hold significant amounts of energy in certain parts of the tree. Junipers hold significant energy in the foliage. When someone interested in bonsai buys a juniper and then prunes a lot of the foliage off they frequently die, this is why. Pines hold their energy in the roots. Deciduous trees hold theirs throughout the tree. Other species have certain timing for an additional flush of growth (Japanese Black Pine) or timing to prune for flowers.
2. If the tree is not healthy, don’t do any work on it unless it involves solving the health issue.
3. If you recently repotted the tree you should avoid pruning so that the foliage mass can help restore the root system that you worked on.
4. The purpose of pruning can include any of the aforementioned reasons – improving structure, controlling and directing growth, or cleaning.
5. We need to understand the stages of bonsai. If you’re not sure what stage your tree is in do some research before.
6. What season we are in can be a great factor in determining if we can prune without damaging the health of our trees. With most coniferous, deciduous, and broadleaf evergreen species the seasons function in the same way. Winter is a period where the tree doesn’t metabolize freely and we often refer to it as dormancy. Spring is a period of heavy growth. There are several periods of using the trees resources to produce more growth, then gaining those resources back through photosynthesis. In Summer some trees can go into a Summer dormancy if the temperatures get above 90° regularly. If you are in a more mild climate your trees may not slow down growth completely. Fall is a time where the trees save energy and focus on thickening branches and roots to help with Winter hardiness.
7. An example of a bad time to prune would be in Spring right after your tree has pushed out a ton of new leaves. If you prune the branches off before the leaves have been able to form a cuticle (finish growing) and reaccumulate energy, then you’re weakening the tree by taking away its ability to gain energy back.
A generally safe bet is the prune in early Spring before buds pop open or additional candles / needles start growing.
I’d like to also state that you can operate outside of these general guidelines, and depending on how you care for your tree afterwards, you can prune at almost any time. However, I would not recommend pruning whenever you please without extensive knowledge and experience.

Cleaning A Chinese Juniper

Cleaning your trees before wiring and styling is just as important as wiring itself. Here are a few photos of before and after of cleaning the interiors to give you an idea of what that looks like:

Before:                                          After:
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Before:                                          After:
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This is a spindly piece of foliage that gets removed before any branch selection is made.
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This is what I started with:
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This is what I finished with:IMG_2993

It isn’t exactly what I wanted, but I recognized myself just wanting to be done, so I left it and I’ll let it grow out a bit and repot it next season to split the trees. This isn’t the final design by any means. It is a pretty good start to a $1 purchase from Walmart 😀

Design and Critique #4 – Pine and Elm Display

3 point bonsai display

Display of Trees:

The trees flow well from the main tree to the sides by placing both the Elm and the companion plant in a direction that the foliage and branching suggest. The stands are also perfectly chosen to contrast the tree on top.

The flow of the Pine is directed towards the left, as is the flow of the Elm. This is shown by the defining branch on the lowest part of the tree combined with the flow of the apex of both trees. You can also see the silhouette of the apex drawing a line to the next tree.

Branching:

The literati styled Pine has a great defining branch on the left that sets the longest part of the tree. This helps it accomplish asymmetry rather than the unrealistic perfect symmetry. The trunk doesn’t have any outrageous bends, but has consistent movement which fits nicely with the literati style.

The Elm has good branching, but the taper from the thick trunk to the smaller branches lets you know that it was developed from a larger trunk chop. I would love to see this same display in Fall to see the yellow elm leaves combined with that fantastic blue pot.

Comments:

I love the display stands for this display. Well chosen and very fitting for the accompanying trees.

The feminine pot is a perfect elegant choice for the pine tree. Flowing rim of the pot with a tapered bottom enhances the movements of the tree without dominating the display.

The Elm has a nontraditional lower branch on the left, but I like it. It really helps to balance the tree and serve as a defining branch.

Next Up:

Winter Bonsai Display

Fundamentals of Bonsai – Summer

Your tree has physiological responses to the heat of Summer. It goes into a semi-dormancy to cope with high temperatures, scorching sun, and preparation for Fall.

Crape Myrtle Flowers

Protecting your tree during Summer is of utmost importance. Almost every tree should be shaded from afternoon sun, especially in the Summer.

Watering

If you miss watering even for a day you may lose trees. This is not the time to be skipping watering, however it happens to be the time for vacation. If someone is coming to water my plants I tell them which plants to water and watch them do it without any instruction first, then I write down everything they have to water and give more specific instructions like “Water it twice as much as you think you should.” It also wouldn’t hurt to have an automatic sprinkler to give it another watering depending when they plan on watering.

Summer Dormancy

Once the temperature reaches the mid 90s your tree will go into a dormancy and cease to photosynthesize in order to prevent significant water loss. Your tree uses water as a cooling agent while transpiration and photosynthesis cease. Watering your tree with scorching hot water will not aid the tree in cooling itself. Make sure to run water out so you water with cool water.

Crape Myrtle Bonsai Tree Flowering

Summer Damage

Certain species of trees can be damaged by leaf burn from the Summer sun. This happens commonly with Japanese Maples among many others. Assuring your tree is shaded from the afternoon sun will greatly aid in reducing leaf burn and overheating problems. It is also common to experience leaf burn on leaves that have no hardened off yet and don’t have a cuticle to protect the leaf from the sun.

Root damage is also common if the pot is not protected from the sun. Black plastic pots, clear glass pots, or even your average bonsai pot can overheat and scorch the roots. Other than a shade cover you can do other things to prevent this by shading pots with foliage from other trees, grouping them together, laying some type of screen over the pot that still allows air to pass through (Window screen, etc.).

Summer Repotting

It is said that some tropical and mediterranean trees like to be repotted in the Summer, but personally I wait until the temperatures reach 50+ degrees regularly and then I repot. This happens to land somewhere between Spring and Summer. I have repotted Ficus, Olive, Schefflera, and Portulacaria Afra in later Summer without any problems, but prefer to do so earlier in Summer to allow a longer window for recovery throughout Summer.

Fundamentals of Bonsai: Fall

Fall is an important time in bonsai. This is where we direct our trees to do as we please. Fertilization, future cold hardiness, and girth in branches and trunks all come during this time.

Vascular Growth

Vascular growth is what the tree focuses on in the Fall. This means that producing leaves is not the priority since we aren’t going to be photosynthesizing much in Winter. All energy accumulated from the photosynthetic process go to storage in the trees cells. This energy accumulation is what drives the Spring flush of growth. Different species store their energy in different places. Pines are typically in the roots, Junipers are in the foliage, and Deciduous trees are evenly spread in the roots, trunk, and branches.

Cold Hardiness

There is also an important nugget of information about cold hardiness. In bonsai we love the highly ramified branches. In order to get those twiggy branches we reduce the cold hardiness of that branch. The more sugars and starches we have inside the branch of a tree, the lower the freezing temperature is. Therefore, highly ramified branches are highly susceptible to cold damage even though the tree as a whole might be able to withstand a much colder temperature.

Energy Management

Energy management is of supreme importance in the Fall. The more you fertilize the more energy the tree stores. When a tree has a lot of energy it produces long internodes, large leaves, and coarse thick branching. When a tree has a small amount of energy it produces short internodes, smaller leaves, and fine twiggy branching.

This is why following blanket statements about fertilization can be so dangerous. If you just fertilize every 4 weeks with a full dose every year, you’re never going to be creating a tree with highly ramified branching and small leaves.

Wire Bite

If your tree is wired, this season must be a watchful one for you. Wire bite on the branching of trees most commonly happens in the Fall due to the trees focus on vascular growth. Checking the branches frequently allows you to stay ahead of the trees growth and remove wires before it damages the branch.

Fundamentals of Bonsai – Spring

Spring is when the tree wakes up from its dormancy in Winter. The daylight length and temperatures increase and this signals to the tree that it is time to wake up. The tree then begins a cycle that it follows through Spring.

Juniper Chinensis Bonsai Shohin

  • Buds begin to swell

  • Leaves emerge and the tree goes into an energy deficit.

  • The first flush of growth hardens off and tree goes into energy positive

The perfect time to repot is while the buds are swelling. While the timing cannot always be perfectly right before the buds break, the closer to bud break (without repotting AFTER the bud break) the better.

When leaves emerge the tree spends some of the saved up energy from Fall to produce foliage with the possibility to generate more sugars and starches. When this happens the energy “bank” so to speak, goes negative. The new leaves are like an investment. Until those leaves harden off and form a cuticle, they do not photosynthesize. Until this happens this investment is a negative overall.

Pruning too much at the wrong time, defoliating, a hard freeze that kills foliage, pest issues that grow out of control, and even missing a day or two of watering can do a significant amount of damage to your tree’s health. While it doesn’t always end in a dead tree immediately, you need to consider this in the long term. You might have a hard freeze one year, prune a little off at the wrong time each season, defoliate in the Summer, and then after a few years you find your tree dead for what appears to be no specific reason.

Cotoneaster Repot Bonsai

This guy died from a late freeze after the first push of growth. I had recently repotted it and it was weak due to that. It never made it out 😦

A better way to understand this is to think of investing a significant portion of your savings into a stock hoping for a consistent return of maybe 7%. Instead of return, your stock plummets and becomes worthless. To be able to do anything with your money you’re going to need an amount of time to recoup the money you lost. If you continue as if you hadn’t lost all of your money in the investment and then spend with the intention to withdraw your invested money, you’ll be negative because you don’t actually have that money. If you have a tree that loses leaves from a freeze and then pushes out new leaves, the tree will have less energy in the bank. If you proceed by delofiating it to get a smaller push of leaves, you’ll find that it doesn’t have enough energy and will possibly die.

The vigor of the growth, length of internodes, size of leaves, and amount of leaves all depends on what you’ve previously done.

Fertilizing frequency and strength play a large part in Spring growth. If you’ve been fertilizing heavily and at the maximum frequency, you’re bound to have a large amount of energy. This will result in a lot of leaves, larger leaves, and longer internodes. The pot size also has an effect. If you fertilize lightly and infrequently, but you have your tree in a large training pot, you will not see small internodes or small leaves. Restricting the area for the roots to grow creates less vigorous growth.

If you’ve repotted a deciduous tree and pruned a large amount of roots, you’ll only see the amount of leaves that the roots can support. For a photo of this see this blog post about the difference.

Let’s go over what we’ve learned:

  • Daylight length and temperature determine when a tree breaks dormancy

  • Fertilizing strength and frequency (are not the only factors, but major factors) correlate with internode length, leaf size, and leaf quantity.

  • A deciduous tree will only push out growth that it can support with its root system.

  • Fertilizing can be throttled with frequency and strength.

  • Energy for Spring growth is stored by the tree in Fall

  • Repotting is best done before the buds break at the beginning of Spring.

  • New leaves take energy to produce and then produce energy when they harden off.

  • Common bonsai techniques (repotting, pruning, defoliation, watering, etc.) performed at the wrong time or late freezes can damage your tree’s health.

Japanese Maple Leaves