Japanese Black Pine bonsai gets a new look

8 months ago Nebby 0

Source: Bonsai Tree Blog.


In November of 2015 one of the trees I imported from Japan was this Japanese Black Pine or Kuromatsu. I cannot recall at the time what attracted me to the tree as in retrospect it is not exactly the most attractive of trees. Its my guess that I must have seen some potential in the tree and the more abstract nature of it. Although I appreciate the timeless beauty and do own several formal and informal pines, they do not hold my attention as long as trees in the bunjingi style do. Trees in this style tend to possess more energy and are certainly more expressive.

Japanese black pine unstyled bonsai tree

Image caption. The tree as purchased. In fact this photo was taken before I had imported it.

As with all trees which I import from Japan, I allowed it to become acclimatized, something which usually takes most species about a season to do. To work on pines requires that the appropriate work be done at the correct time. So although the tree may be healthy, before beginning to work on it in earnest it is best to wait until its timing is on. This is why I waited 2 years before performing the restyling exercise which I will now proceed to discuss with you.

Preparatory work

Work on the tree sort of began the following season on the tree, so back in 2016. What was done was really light work though, nothing too intense. At the time I completed the following:

1. Removed all old copper wire

Copper wire develops a great colour when it oxidizes, it essentially ends up as a very dark brown or even black. It is therefore less visible, however this of course means that it is easier to overlook some wire when removing it, resulting in some serious wire bite. A lot of people ask me when wire should be removed from pines. The answer is not as simple as they would like as it will depend on how fast your tree is growing. As wiring is typically done in winter, the growing season is ahead and in young trees on new branches you will start getting wire bite in a matter of weeks. In older trees it could be longer of course as they are not growing as fast anymore. What I essentially look out for is wire bite. When the wire begins biting in, then I remove the wire but not before. Remove the wire too quickly and the branch will return back to its original position and you will have to re-wire it the following season. From an environmental perspective, when removing copper wire, please do not just throw it in with other green clippings. Rather put it into a container which you can take to your local scrap dealer. Its less about the recyclable value and more about doing the green thing.

Restyling a Japanese black pine bonsai tree - the beginning.

Image caption. Removing the old copper wire, by cutting it off using the appropriate wire cutter.

2. Changed the pot

The training pot which the tree was in was just that, a training pot. However I felt that at this stage the tree could go into something a little nicer, like a more free-formed nanban type container. I particularly liked the more open feel of the nanban which seemed to visually extend the surface of the root ball. The training pot’s vertical sides brought the composition to an abrupt end.

I subsequently decided that the container was not right for the current stage of the trees development. The harsh growing conditions the tree will experience in such a shallow, open container will greatly retard its growth. So I decided to rather put it into a Japanese tokonameware drum style container which would provide more volume for the roots to develop in, and as it is deeper water retention would be better.

Japanese black pine growing medium

Image caption. New growing medium of Akadama, pumice and Leca. Charcoal was also added.

With bonsai it is often about planning. Pines are no exception. Realizing that I would not be able to repot the tree and decandle in the same season, repotting had to be considered now. The growing medium the tree was in when imported was mainly akadama and pumice; however the akadama had largely broken down retarding drainage and increasing water retention. Both these factors combined resulted in slowing down the growth of the tree, another reason why repotting would be a good idea before doing a major restyle. When you repot a tree it is revitalized and this would be a good condition for the tree to be in when I began working on it. So I proceeded to remove the old soil from the root ball and replaced it with new growing medium. I used a roughly 1:1 mix of fine akadama and fine pumice. I added charcoal too, about a large scoop. 

3. Removed old needles

I removed all the old needles with tweezers. These old needles essentially block sunlight from getting to the inner buds, they harbor pests which make their nests within the clutter and as they are now a few seasons old, they do not serve the tree in any way as food factories. Lastly from a more visual aspect, bunjingi trees have a more open, sparse look and feel to them. This is of course completely in context of the harsh environment you are trying to suggest shaped this tree. 

4. Fertilized

Pines must be healthy before you can think of working on them. This is really no different to any other tree though. So right through the season, I fertilized well with BonsaiBoost, replacing the bags monthly. For a much more indepth look at fertilizing please read this blog post

Styling the tree

Check back soon for the 2nd part of this blog, or subscribe and never miss updates in the future.

Read these other posts on Japanese black pine interim

Here’s a sneak peak of the end result though.

Japanese black pine bonsai tree final result