Tag Archives: Guide

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.

Fundamentals of Bonsai – Basic Physiology

There is a lot of confusion when you begin the bonsai journey. You’ll hear suggestions from everyone about how to do everything. One thing that helps is understanding why you’re doing something. Understanding the physiology of your plants will help dramatically with that.

I wanted to start with this photo that has a bit of information. You don’t have to memorize this to practice bonsai by any means, but I’ll go over the important parts.

Plant Physiology

Koning, Ross E. 1994. Plant Basics. Plant Physiology Information Website. http://plantphys.info/plant_physiology/plantbasics1.shtml. (6-2-2018)

Trees need 4 things to survive:

  • Water

  • Sunlight

  • Air

  • Nutrients

The Leaf

Leaves are responsible for the sunlight and movement of water. Leaves photosynthesize and send the sugars and starches created to the plant via the phloem. As water evaporates in the leaves the process of transpiration occurs. Transpiration in essence “pulls” a chain of water molecules from the roots up to the leaf to replace the loss of water. The cuticle is a waxy covering on the leaf that stops moisture loss once the leaf has fully “developed.” Once a leaf has its cuticle it begins photosynthesizing and accumulating energy. This happens once a leaf has reached its mature size after breaking out of the bud, changed to a darker color, and has become less flexible.

There are several techniques used in bonsai that involve leaves, namely: full and partial defoliation, leaf cutting, pruning, watering, development of branches and trunk, and allocation of resources throughout the tree.

Branches are like roads, the more they are used the bigger they get. If one branch has 20 leaves and another has 5, the branch with 20 leaves will thicken quicker than the branch with 5 leaves. This is because more energy is being created and more water is being moved there from the water loss of the leaves. We learn from this that foliar mass = girth.

The Roots

Roots are responsible for the uptake of water, oxygen and nutrients. There needs to be a balance of water and oxygen in the soil for this to take place and not starve the plant for either water or oxygen. Roots move water and nutrients to the plant through the xylem.

Large roots help to anchor trees in nature. Small fine roots are the main roots that absorb moisture and nutrients. Roots function the same way branches do in the sense that the more fine roots you have attached to a larger root, the bigger it will get.

In bonsai we repot anywhere from every year to every 10 years depending on the needs of the tree. We prune the roots and style them much like we do to the branches above the soil line.

The Stem

The trunk and branches have bark which aids in retaining moisture. I’ll talk more about the stem as needed in further discussions, but what you need to know is: the xylem moves water and nutrients from roots to leaves, phloem moves energy to the tree from the leaves, and cambium helps the tree get thicker and indicates the tree is still living by showing a green tissue layer under the bark.

Wiring and bending a tree can be more difficult depending on the species of the tree. Different species have varying abilities to bend, and this is due to the changes in the xylem, phloem, cambium, amount of water moved (water loss due to transpiration), and bark.

Chinese Elm Bonsai Care Guide

Chinese Elm – Ulmus Parviflora

Updated: 7/17/2018


The best time to trim deciduous trees is typically Fall after the leaves are dropping. During the growing season be sure to wait until the new leaves have hardened off before pruning back.

Cutting off large branches without leaving several close buds can easily result in dieback of the pruned area. This is common with elms and needs to be done apart from repotting to give the roots strength to rebuild the branches without dying back.


Chinese Elms prefer full sun with protection from afternoon sun or partial shade. Early morning sun is the best sun to give.


The Chinese Elm is hardy down to 10 degrees and can be protected by in ground storage in Winter, or by insulating the pot. Be aware that this can vary depending on how well you handle the tree’s fertilization and foliage in Fall. Twig dieback can occur if not protected from the Winter temperatures. Almost all trees in a bonsai pot need protection once temperatures drop below freezing due to the lack of protection for the roots.


Wiring your Chinese Elm can be done to branches at all times throughout the year, but only do the shoots once they have become slightly woody. If wiring in the Fall be vigilant in checking the wire to avoid wire biting into the bark.


The fastest way to propagate the Chinese Elm is with 6 inch cuttings taken with sharp, clean scissors in the Summer. Place in a glass of water and roots will soon develop. Repot rooted cutting in a quality bonsai soil or a mixture of 2 parts loam, 1 part peat moss, and 1 part sand.

Additional Resources:

Bonsai Reddit: Branch Thickening

Chinese Elm Yearly Progression

Bonsai Reddit: Wild Crazy Bunjin Style

Bonsai Reddit: Chinese Elm Winter Care

Bonsai Tool Chest Chinese Elm Guide

For care guides on other species head to my Bonsai Information page.

Seasonal Bonsai Care Guide

Knowing what to do in each season can be overwhelming for new bonsai enthusiasts. Having a solid understanding of what your tree is doing in each season is vital to taking care of your tree. You can use this list as a general guide. Be sure to check that your tree species doesn’t require special care outside of these guidelines.


What we do when we finally see those buds swelling.

In Spring we get giddy because we have so many new activities that we couldn’t do in Winter. Much work to be done and more time to spend outside.

  • Match pots with trees before repotting! Consider size, shape and overall look.

  • Repot trees and protect them from strong winds and frost (Ideally as new leaf buds are about to break)

  • Make sweet root cuttings from repotted trees if the species allows

  • Collect previously marked yamadori

  • Check local nurseries for the rare bonsai stock (Home Depot and Lowes have 1 year plant guarantees. Great for beginners learning to water and keep them alive…just saying)

  • Transplant any trees from or to the ground for trunk development

  • Wire trees that were not root pruned or repotted

  • Prune any branches that were damaged by frost

  • Stay on top of those clip-and-grow Boxwoods, Crape Myrtles, Chinese Elms, etc if you’re going that route

  • Prepare any trees that will be exhibited later

  • Check for pests and any potential diseases

  • Document with photos and journals to be able to display changes over time

  • Inspect trees in refinement frequently and keep branches trimmed back to ramify.

  • Start air layers


Water like you know what you’re doing…

Summer may be free time for you teachers out there, but we’re getting work done. Plenty to do even though Spring has come and gone. As temperatures rise we need to keep an eye on our plants and their water needs.

  • Keep an eye on your trees checking for water needs. Wind and high temperatures can dramatically increase the need for water.

  • Check for pests and diseases.

  • Defoliation can be done throughout Summer

  • Document changes before with photos or journals

  • Wiring and styling can be performed

  • Check wiring from Spring on fast growing trees to make sure it isn’t cutting into branches

  • Regularly fertilize and weed to prevent any nutrients to be taken from the tree

  • Make sure any tree sitters are reliable and know how to water the trees

  • Treat jinned branches with lime sulphur

  • Switch to low nitrogen fertilizers near end of Summer

  • Cut air layers that have rooted, and take cuttings in order to propagate more material to play with


Make sure your yamadori scouting trips don’t start with a fall.

The Fall colors of your trees will be worth the wait. Many people see Autumn as a time of resting in terms of bonsai work, but this is a vital and exciting time. Forgetting to fertilize would be a sad mistake.

  • Take photos of your color changing trees so you don’t regret it later!

  • Feed trees with low nitrogen (or no nitrogen) fertilizers.

  • This is the most important time to fertilize, DON’T FORGET IT! 10-10-10 is better than no fertilizer if you don’t have low nitrogen fertilizer!

  • Be vigilant in checking wire as trunks and branches will be thickening during this season.

  • Remove excessive flowers and fruit to focus energy on growth.

  • Keep trees clean by removing leaves to keep away unwanted diseases.

  • Take hardwood cuttings and collect seeds.

  • Sow seed that require stratification now.

  • Make any preparations for Winter protection that you will need.

  • Keep any eye on water retention in your soil mixes.

  • In hotter areas this is a great time to hike and scout out more yamadori for Spring


“I am cuuuuuuuuuuute.”

The leafless trees have awakened! Fine ramification is finally able to be appreciated at it fullest. Take this time to prepare for the coming season, protect your trees so you have something to do in Spring, and restock on materials. Don’t forget about winter exhibitions!

  • Protect fine branches as they are the least hardy.

  • Depending on location, you can moves pots to the ground, mulch, cover, or bring trees inside to protect from Winter.

  • Photograph and document trees.

  • Take notes from any previous wiring, styling, or pruning that was done and see how improvements could be made.

  • Correct any mistakes in styling that was carried out during the growing seasons.

  • In early Winter prune back terminal buds to encourage bad-budding in the Spring.

  • Prepare any trees for a Winter exhibition if you’ll be displaying trees.

  • Purchase materials for upcoming season: wire, soil, pots, paste, etc.

  • Get soil sifted and ready for repotting season.

  • Clean pots, benches, tools (oil and sharpen), and finish any organization to help Spring activities run smoothly.

  • Do not forget to water trees! They don’t need too much water, but can’t be forgotten.

  • Leave trees in the sun if possible, they don’t photosynthesize, but the sun is still the best for them.

  • Do not fertilize.

  • More yamadori scouting, because who doesn’t want more trees?!

Desert Dwellers

Yes, this is how we feel about you people with plenty of species decisions to make…

For those of us in the hot desert climates that have wild ranges of highs and lows, I present to you the amazing resource of PhoenixBonsai.com. They have countless resources for us Mojave Desert enthusiasts, and we may or may not worship them…

To learn about specific species and their care head to my Bonsai Information page

Bonsai Resources

Updated: 7/19/2018

Worldwide Bonsai Gardens, Nurseries, and Shops:

Worldwide Map



https://www.bonsaitree.co.za/blogs/tree-talk/the-art-of-watering – Must read for beginners!

https://www.evergreengardenworks.com/articles.htm– Great articles!


http://www.magiminiland.org/OtherArchived/HowTreesAdapt.pdf – Bonsai Plant Physiology









Pot Vendors:

Rocky Mountain Bonsai has a solid list of pot vendors

Soil Discussions:

Adamaskwhy(As a side note, High Desert Bonsai-ers, Benny Kim runs 50% pumice with 50% lava. I add a bit of Turface personally)

Water Retention Comparison Video

Freeze Thaw Cycles Comparison Video


Reddit FAQ

Forums and Discussion:

Bonsai Reddit

Mirai Forum

Youtube Channels:

Nigel Saunders

The Bonsai Student

Local Southern California Clubs:

Los Angeles:

Dai Ichi Bonsai Kai
Ko Yu Kai Shohin Club
Descanso Bonsai Society
California Bonsai Society
Santa Anita Bonsai Society
Sansui Kai of Southern California
Conejo Valley Bonsai Society
South Coast Bonsai Association
Marina Bonsai Club
Sanpu Kai
Shohin Bonsai Society (Arcadia)
Baiko-en Bonsai Kenkyu Kai (Arcadia)
San Gabriel Valley Satsuki Bonsai Society

Orange County:
Kofu Bonsai Kai
Orange County Bonsai Society
Orange Empire Bonsai Society
Satsuki Bonsai Society of Orange County
Vietnamese Bonsai Society
Hoi Bonsai Viet (Westminster)

Inland Empire:
Chino Bonsai Club
Inland Empire Bonsai

San Diego County:
San Diego Bonsai Society
San Pu Kai Bonsai Club

North of L.A.:
Bonsai Club of Santa Barbara
Santa Maria Bonsai Club
Central Coast Bonsai Club (Nipomo)
*California Bonsai Studio

*Not a club, but has $10 training meetings and free monthly workshops, so it’s like a club

Southern California Bonsai Nurseries:

Benny Kim

Kimura Bonsai

Chikugo-En Nursery

House of Bonsai

To learn about specific species and their care head to my Bonsai Information page