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How to Prune Bonsai for Shape & Structure

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Suppose the goal is to develop a workable tree trunk in the first two phases, the third phase. In that case, our focus is on branches, and in the overlapping fourth phase, we’re in maintenance mode, including ramification development.

The development of a Bonsai tree is inextricably linked to pruning or pinching, the removal of roots and shoots to create a work of art. The objective of pruning is three-fold: shaping the stock, directing growth to underdeveloped areas, and boosting ramifications.  

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How To Prune A Lemon Tree
How To Prune A Lemon Tree

Start With The End In Sight

It is always easier to achieve your goals if success is quantified – knowing the outcome you’re working towards. I’ve outlined some of what competition judges consider when viewing Bonsai trees so that you know what to look out for when pruning.

Pruning For Shape & Structure of Bonsai Trees
Pruning For Shape & Structure of Bonsai Trees

Suitability Of Species For Bonsai.

A suitable species for bonsai is a tree that can reduce leaf size. Some unsuitable species include large palmate (Horse Chestnut) and large pinnate (Mountain Ash).

Trunk Taper

Trunk taper is very important—a major factor in creating the impression of age and grandeur in many species and styles.

Good Truck Taper
Good Truck Taper

General Health And Wellbeing of The Tree.

  • Trunk; was an orientation selected that best shows the trunk’s character?
  • Bark; does it show maturity and plating? Is it clean and free from algae?
  • Foliage; Judges look at leaf color and size. There should be no obvious blemishes or evidence of wind burn.

Branch positioning, including ramification

Branch development is a large category and includes several aspects; The proper placement of branches is one. The development of a fine network of secondary and tertiary branches is another. Finally, the branches need to be thick enough and tapered, in other words, in good proportion with the trunk, appearing as mature as the trunk itself.

  • Is the main largest branch and the counterbalance branch well defined?
  • Are the main branches positioned correctly, without obstructing or obscuring one another?
  • Was it properly pruned so that no stumps show? Are pruning cuttings properly completed?
  • Is the negative space between the branches distinct?
  • Does the shape of the branches make sense to the style and trunk movement?
  • Is the apex well-defined?
Branch Structure & Ramification
Branch Structure & Ramification

Surface Roots or Nebari (if appropriate to the species)

Nebari plays a crucial role in defining the front of the tree and is one of the most important factors to observe for styling a good tree and one that is difficult to correct.

Deadwood Effects

Deadwood, if any, should enhance the natural aspect of the work and must be well defined (jin, shari, and uro) without visible use of power tools leaving carving marks.

Wiring

Correct, minimal, and discrete wiring, but strong enough to hold branches in place without damaging the bark.  

Surface Dressing

Judges are looking for the appropriate use of moss, surface material, and the definite lack of weeds.

Aesthetics

Judges look to see that your Bonsai is presented at the correct angle, demonstrating a balanced tree. Of importance are the respective volumes of foliage and branches, their comparison to each other, and the harmony of tree proportions

They review the tree’s style, particularly looking for a strong impression of depth. Finally, does your bonsai replicate nature’s artistry, emphasizing character, or does it look contrived and artificial?

Other Presentation Criteria

Judges want to find an absence of pests or diseases, the appropriate use of a pot (shape, color, and texture), and the tree’s position in the pot. Finally, your choice of display stand, the appropriateness of size, color, and design matter.

Tree Growth Principles

Get basic knowledge about a tree growing before going into greater detail about either method. This will clarify for us the proper way to prune bonsai trees.

Apical dominance is a natural propensity for trees to thrive. This indicates that the plant’s main stem, which is in the center, grows more strongly than its lateral stems. For instance, the main stem is more prominent on a branch than the side twigs.

Due to a built-in mechanism, trees are encouraged to grow taller to avoid being shaded by neighboring trees.

The inner and lower branches of the tree will eventually die if growth is concentrated on the top and outside margins, and the top branches will grow out of proportion, which is undesirable for bonsai aesthetics.

Understanding a tree’s natural development patterns enables us to utilize pruning methods to mitigate the consequences of apical dominance.

We know we must prune a tree’s top and outside parts more carefully since dominating growth happens on a tree’s primary stems.

This provides us control over the tree’s growth and design by forcing the tree to shift growth to the inner and lower regions.

Bonsai Branch Structure

Pruning For Bonsai For Branch Structure
Pruning For Bonsai For Branch Structure

It is best to grow as many branches as possible early so you can cut them off later. I used to remove all the branches that didn’t conform to my vision for the tree, only to discover that the branches I imagined using failed to grow.

As a result, I now try and keep as many branches as possible and only remove those that become an issue, such as creating reverse taper or causing crowdedness.

You will create the fundamental branch structure using the branch sacrificial technique in the early phases of your bonsai development.

The method entails growing branches for as long as required to achieve a smooth transition between the girth of the trunk and the branches.

Although it can be difficult to describe what is attractive, your choices must consider the horticultural and aesthetic implications.

Horticulturally, the xylem in a pencil-thick branch cannot support a branch with many ramifications. Aesthetically, a branch that grows from a  thick trunk will look out of place if too thin.

If you start constructing ramifications and your branch is not yet thick enough to correct it, you’ll have to undo all the ramifications you’ve already built, which can cost you several years.

It is advisable to stop all side-development for branches and concentrate on directing auxins, which are located in the growing tip and lead to branch extension, to a single growing tip.

This forces the branch to develop substances to support the longer branch. Also, note that if the wind injures plants, the girth expansion is a product of the wound healing, probably due to the formed scar tissue.

This also happens when we cause tiny cracks when we wire the branches.

Cut the branch back as soon as the join is thick enough. The general pruning rule of removing only a third of a branch doesn’t apply here.

Repeatedly cutting a branch back to a third of its length forces redirections and ramifications. The cutback’s severy depends on the tree’s vertical growth potential. It is worth it to take your time (years) to create an effective branch structure.

Utilizing sacrificed branches to help heal previous scars is an added advantage, particularly if the branch is directly above the scar.

The scar will callus over fast because the xylem used for growing a now absent branch can be used for healing. Still, scars are best healed when the tree is still in the ground, so take care not to be too aggressive. Once the tree is moved out of the ground into a container, the process takes a bit longer, and healing may never happen.

Without a doubt, the most important way to train a Bonsai is to prune it regularly. There are two different techniques: Maintenance-pruning, to maintain and refine the existing shape of a Bonsai, and structural-pruning, which involves more rigorous pruning to give a tree its basic shape.

Structural Bonsai Pruning

Pruning Long Branches on a Bonsai
Pruning Long Branches on a Bonsai

Large branches must be pruned to give a tree its fundamental shape. Deciding which branches to keep and which to cut can be challenging, and it is an activity that cannot be undone.

Structural bonsai pruning is typically performed when the tree is young and still needs to be groomed for a particular bonsai style. It can put the tree under a lot of stress because it entails significant modifications and the removal of vital branches.

Structural pruning must be only done at the appropriate time of year, typically in the spring or fall, when the tree is dormant.

Depending on the species, the season, and the circumstances surrounding the plant’s re Bonsai pruning, without a doubt, is an essential aspect of creating and maintaining the shape of your plant.

The two main types of pruning are maintenance and structural.

Structural pruning is typically performed when a plant is young and needs to be educated to develop a certain bonsai style. Because it calls for drastic alterations and pulling back branches, it could be upsetting. Because of this, you should only prune when the tree is dormant at specific year periods.

It typically occurs in the spring or autumn but depends on the specific tree. A Ficus Bonsai, for example, has a different cycle than a Juniper.

Invest in quality tools like twig shears to prune any lengthy stems and a concave cutter for larger branches. For cutting leaves, use long-handled scissors.

If you sharpened the equipment for smooth cuts, that would assist. Any cuts should be closed with a paste or sealant to speed healing.

It’s helpful to be aware of the four main bonsai forms: moyohgi, shakan, chokkan, and bunjingi, to select the plant’s natural preference and work with that.

Bonsai Maintenance Pruning

It is during the growing season that trees flourish and need some restraining. Also, removing energized growth can redirect that energy to smaller branches you wish to boost. For instance, limiting the food-producing top branches will boost the growth of smaller branches as the plant empowers them to grow foliage and photosynthesize.

Maintenance pruning aims to preserve and improve a tree’s shape. It is crucial to constantly prune these growth zones to promote growth closer to the interior sections of the tree since, as was previously said, trees will concentrate most of their growth on parts most exposed to light, the top and sides.

The WHEN of Bonsai Maintenance Pruning

During the growing season, which for outdoor bonsai is typically from March to September, maintenance pruning can be done. Indoor bonsai may need maintenance pruning throughout the year.

The HOW of Bonsai Maintenance Pruning

The Tools Required For Pruning Bonsai
The Tools Required For Pruning Bonsai

Have your tools ready. You’ll need shears and a concave cutter for pruning. Use bonsai clippers and not scissors. It’s a good idea to invest in sharp tools as that would give your bonsai a more refined appearance, and the cuts will heal faster.

Do not be afraid to prune your bonsai frequently, as it encourages the tree to produce thick foliage and boosts growth.

Pinching is preferable to cutting when dealing with pine trees and some other conifers. The cuttings may develop grey, dead foliage when pruning some conifer species with shears, cutters, or scissors.

Holding the tip of the shot between your thumb and pointing finger and carefully pull it away. You will avoid dead ends or brown shoots because they snap at their weakest point. Pruning and pinching requirements vary according to the species; some even require a combination.

Defoliation is a different type of Bonsai pruning that entails removing deciduous trees’ leaves in the summer to stimulate new leaf growth. This method is used to promote ramification while reducing the size of the tree’s leaves.

Basic Maintenance Pruning Guidelines

Identifying leaf pairs and removing one from each pair is necessary for deciduous trees. You can take all the leaves off the bonsai during the summer.

Defoliation is a process that promotes the growth of new, smaller leaves and is crucial for bonsai tree maintenance.

Healthy deciduous trees that haven’t been re-potted recently are ideal defoliation candidates, specifically Elm, Oak, and Ficus. Start by only defoliating a third of the tree at a time if you are a newbie.

Bud pinching is better suitable for pines and some conifers and requires only partial removal of leaves by gripping the needles between your thumb and forefinger and twisting them off.

Tool usage can result in the development of black, dead foliage in some conifers. Practice makes perfect.

Simplify Gardening Tips

  • Keep the top of the tree perfectly pruned as there’s more foliage at the top. It will ensure balanced growth for the entire tree.
  • It’s important to know that all trees are sensitive to pruning, and you should only prune during the season of strong growth. Also, the timing of pruning matters, depending on what type of bonsai you have.
  • If you’re a beginner, don’t remove more than 25-30% of the foliage at a time. Prune gently, pause while doing so and observe the tree from different angles to determine if you need to remove more foliage.
  • You must also know that it’s better to shorten the branches than completely remove them. It goes without saying that once you unnecessarily remove something from your bonsai, you can’t glue it back on.
  • Lastly, use proper tools with sharp blades to remove the thick branches. There’s a product called “cut paste” that you can apply to the cuts to prevent any infections on the tree.

Summary

Trimming thick branches normally leaves unsightly scars; however, specialized concave cutters can greatly minimize scarring effects.

Large Scar on Field Grown Bonsai
Large Scar on Field Grown Bonsai

We advise using a cut paste readily accessible at most online bonsai stores to close major wounds. The paste helps the tree heal more quickly and prevents infections from spreading to the wounds.

Up to one-third of a healthy tree’s leaves can be pruned off without causing problems. Most experts suggest carrying out only one significant maintenance task at a time (or even once a year).

For instance, if you structure-prune this spring, you should wait until the next spring, when the tree has fully recovered from the structure-pruning, to undertake any repotting or root cutting.

Bonsai Basic Fundamentals

Bonsai is an art; to become good at bonsai, you must master the fundamentals. These include the following but are not limited to. Click the links in the table to learn more about each subject.

PlacementPruningStyle / Form
WateringWiringBuying Bonsai
FertilizerDefoliationNursery Stock
RepottingDeadwoodGrowing from Cuttings
SoilSurface RootsGrowing from Seed
Pot SelectionTrunk
The fundamentals of Growing Bonsai

FAQs on Pruning bonsai

In Closing

Understanding a tree’s natural development patterns enables us to utilize pruning methods to mitigate the consequences of apical dominance. We know we must prune a tree’s top and outside parts more carefully since dominating growth happens on a tree’s primary stems.

This provides us control over the tree’s growth and design by forcing the tree to shift growth to the inner and lower regions.

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