Basic care of bonsai Zelkova (Japanese Elm)

  Mistral Bonsai       26/08/2020
Basic care of bonsai Zelkova (Japanese Elm)

Do you have a Zelkova bonsai? Do you know how to take care of it? Do you have any doubts about what to do and when to do it? Don’t worry, today we explain how to take care of your bonsai Zelkova, or Japanese elm, and how to sustain it. Enjoy this wonderful species that is very good for bonsai.

As a curiosity, the Zelkova parvifolia or Japanese elm is known by the name of “Kejaki”. This species is native from Northern Japan.

Below, we explain the basic care to have a beautiful bonsai Zelkova.


The Zelkova is an extremely resistant tree in its cultivation for bonsai and can be both indoors and outdoors.

  • Outdoors:

In Mediterranean climate zones it is ideal to be located outside, so it can enjoy the sun. With the arrival of winter and the drop in temperatures, this bonsai usually loses its leaves. Behaving like a deciduous tree. In the following spring it will sprout again.

  • Indoors:

This kind of bonsai can also adapt perfectly to the interior of our houses. In our home we enjoy a more or less constant temperature and humidity. This species likes light a lot. So do not forget to always place it in a bright room and near a large window that allows as much light as possible. In spring we can take the bonsai outside so it can take in the benefits of that season and thus grow healthier. In summer, it is advisable to put it back inside to avoid that high temperatures and the sun wreak havoc on your bonsai.


Like all bonsai, irrigation will depend on its location (outside or inside) and the microenvironment in which your bonsai is located.

To properly water your bonsai, remember the advice we have always given you. Verify that the surface layer of the substrate is dry. If so, it is time to water. We will do it with plenty of water, letting the substrate get well soaked. Then, we will let the remaining water drain through the ceramic holes. In no case will we leave water in a plate or tray. This would cause the bonsai roots to rot and, therefore, the bonsai to die.

If, on the contrary, the surface layer of the substrate is still wet, we will not water at that time and we will wait.


The fertiliser of your Zelkova bonsai must follow the standard fertiliser calendar, as it is a species of fast growing. For what you must fertilise it frequently.

In spring and summer use a fertilizer that is for growth, rich in nitrogen.

In autumn use a fertilizer lower in nitrogen and rich in potassium (autumn fertiliser), so that the tree can store energy and thus resist winter.

Once explained this, I suggest the following:

  1. Fertilise it from the beginning of spring until the beginning of the rise in summer temperatures, the growth fertilizers that I recommend are; Joy Tamahi (N5-P4-K1) or Biogold (N5,5-P6,5-K3,5), together with the nutribonsai (balanced fertilizer).
  2. After the peak of summer heat drops, until the end of autumn, I recommend Hanakogoro (N4-P5-K1) or Tosho (N4-P6-K3)

Remember that: N = Nitrogen, P = Phosphorus and K = Potassium


Pinching is the technique we use to maintain the silhouette of our bonsai. We can do it throughout the year. It consists in cutting with pincer scissors those sprouts that went out of the line of the silhouette of the bonsai. This does not create any stress to the tree, nor will you cause scars.

Pinching bonsái Zelkova


This technique should be done to your bonsai during the spring, just before sprouting, in this way you ensure that the tree does not suffer and that it recovers easier. Normally we can transplant every 2 or 3 years. This will depend on the type of substrate on which your bonsai is.


Pruning is a technique that helps to keep your tree aesthetically correct, eliminate unnecessary branches and create the silhouette of your bonsai. There are three types of pruning, each one is used at a different time:

  1. Initial Pruning: When you buy a nursery tree or a yamadori[1] and it starts its journey to become a bonsai.
  2. Structural pruning: When it is already a bonsai, but it is halfway there and you must eliminate some branches that came out later.
  3. Maintenance pruning: When the tree is already formed and you have the design done.

The pruning of maintenance (pruning of some additional growth), can be performed in spring, summer and autumn, since this pruning is very small. With some pruning shears we will correct some imperfections in the design of the silhouette or of the foliage box (floors).

The structural pruning (pruning of secondary branches) is also suitable to perform in spring, since the circulation of the sap will help to heal the cuts.

Initial pruning (or training pruning) as it is a drastic pruning, must be carried out at the time the sap’s journey begins, that is, at the beginning of spring. The right time is when the buds swell, at the beginning of the activity of our Zelkova. Doing so at that time the wounds of the cuts will be able to heal perfectly. When winter comes, they will be closed.


In order to have your bonsai aesthetically beautiful, the branching must be well constructed. If there is a branch that is located in an inappropriate place, we must use the wire to correct its direction and put it in its place.

Wiring can be done at any time of the year, considering that, if we need to bend or move the branch’s position a lot, it must be done at the time of greatest circulation of sap (in spring). Bonsai outdoors, when they lose their leaves, is the ideal time to wire all their branches and correct or refine their design.

Remember that there is no set time to remove the wire. This will depend on the growth of your bonsai. You can have several Zelkova bonsai, wire them the same day and you will see that you will remove the wire at different times. Their growth is not the same. When should you remove the wire? When you see that the branch is slightly swollen and the wire is seen to be very tight. At this time, you must cut the wire to prevent it from digging into the branch or trunk and leaving a scar on your bonsai.

If you wish to read more about how to choose the right wire to apply this technique, don’t miss our blog: “Do you know how to select the right wire for your bonsai?”


The technique of defoliation seeks to generate smaller leaves. If your Zelkova still has slightly large leaves, this technique can help you. Normally this technique is done after the ripening of the spring buds. That would be between May and September. The idea is to cut all the leaves, leaving only the petiole[2]. That encourages a second spring in the tree, so more leaves and smaller than the previous ones will come out. This technique can only be applied to trees that are healthy.


A healthy bonsai is usually more resistant to pests and diseases. Even so, our bonsai can suffer some plague or illness throughout its life. The most common that affect it are:

  • The anthracnose

Disease caused by a fungus. This causes the leaves and branches to rot. Its treatment is the application of an organic fungicide and prevention can be done by using a cupric fungicide. It happens because there is not enough sun and does not enjoy air currents.

  • The red spider

When the leaves are filled with small bites, they are undoubtedly because of mites; the red spider is the most common. It is treated with a good acaricide.

  • Chlorosis

When the leaves turn yellow it indicates that our bonsai lacks iron. This disease is treated by supplying iron chelates to our bonsai. Ferrobonsai is ideal for treating chlorosis.

As you can see, we have taken a tour of all the most basic aspects you need to know for the maintenance of your bonsai Zelkova.

Bonsai is passion, but also organization and care. And I want to finish this article by giving you a very important term in Japanese.

“Muchigomi”, means the daily company you give your bonsai to grow together. Your bonsai Zelkova and you. Until next time


[1] Yamadori = It is a tree that was rescued from the mountain, planted in a pot to begin its path as a bonsai.

[2] The petiole is the appendix (shank) that joins the leaf with the Branch.


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About the Author

Mistral Bonsai

In Mistral Bonsai we are a communication team, technicians and masters committed from the first day to disseminating the wonderful art of bonsai. A world that offers many things to share. We believe that a bonsai is a tree with a soul, unique and unrepeatable. Another of our most essential pillars is, how could it be otherwise, our close commitment to the preservation of the environment and nature.