Rebuilding a Japanese Maple

Rebuilding a Japanese Maple

Now that all the defoliating has been done to the refined trees here at Aichien, it was time to work on the project trees.  This time, Mr. Tanaka tasked me with this large Japanese maple that is being redeveloped.  All the branches growing on the tree have been grafted with a better leaf quality.  The tree was allowed to grow during the Spring and now that Summer is right around the corner, this was a good time to continue it’s development.  The goal at this point is to wire the new branches and graft three areas that need branches.  In this post, I will talk about the grafting technique I used, wound management and a hint about defoliating.

Here is a side by side of the original leaf (1 left) on the tree versus the new leaf (2 right) that has been grafted on.  The reason why leaf 1 was replaced is because it has a rounded droopy appearance a opposed to leaf 2.  Overall, a tree that has leaf 1 tends to look wilted all the time whereas leaf 2 has a more upright and healthy feeling that most of us are accustomed too with a Japanese Maple.  Of course, because of the lack of popularity with leaf 1, the price of the tree is much lower then if it had leaf 2.  So for all these various reasons, the leaf was changed.

Here is an example of a tree that has the wilted looking foliage.

and here is an example of a maple that has a more desirable leaf characteristic.  Personally, I wouldn’t mind having both styles. ;o)

What is Approach Grafting ? and Some Terms

Approach grafting is pretty much using two self sustaining branches and fusing them together.  In this case, I’m going to take some of the long branches from one part of this tree and attaching it to another part of the tree.  The nice thing about approach grafting is that both branches are still being feed so there isn’t any water flow cut off. The chances of a successful union are much higher and reliable with an approach graft.

The best time to do an approach graft is during the growing season.

Here are a few terms that I will use to explain the approach graft operation:

Scion– The new branch I used for grafting

Stock– The branch I’m grafting on to

Graft union– the point where the Scion and Stock are attached.

Also, knowing a few tree plant biology terms wouldn’t hurt either.  You’ll hear me use the word Cambium a lot.  That is the area of the scion and stock that have to meet to achieve successful graft.

Lets Get to Work!

Before I start on the grafting, I took care of two wounds on the base of the trunk.  We found this dead area under the bark and needed to take some steps to help it continue to callus and close up.  As in previous post, I took a sharp gouge and lightly cut into the surrounding callus.  This will help reactive it and its continued growth.  I then applied a good amount of liquid cut paste to seal it all up.

One importuning thing that people don’t really talk about is the hard surface that a callus needs to grow on.  In this case, the surface is the hard wood.  Sometimes, this hardwood can be soft or rotted out because of exposure to water or humidity.  If that was the case on this tree, the callus will grow slightly and stop.  If we find a deciduous tree that has a rotted out wound, we would have to dig the rotted wood out and fill it with a hard putty or cement to give the callus a firm surface to form on.  Luckily, this time, the hard wood is still hard.

On With the Grafting!

The first thing I did was look through the tree and figure out where I needed new branches.  Here is an example of an area that I need to add a branch.

Once I decided where to graft, I used a sharp clean saw to make the cut.  The depth of the cut is dependent on how thick the scion branch is.  In this case, the cut was not very deep.  Note how the cut is green.  This tells me that the area is alive and able to take a graft.  If I cut into the stock branch and saw only brown dry wood, obviously I would have to find a different area to graft.  Next, I took a sharp clean grafting knife and slightly enlarged the cut to make it wide enough to accept the scion branch.

Here I placed the scion branch into the stock to check for fit.  Note how the scion branch is green at the graft union?

For a better chance of a successful graft, I lightly scraped away the bark to exposed the cambium layer.  If I can match the scion branch cambium with the stock branch cambium the graft will take faster.

Once I feel that the fit of the graft union is good, I used a small nail with a rubber pad to hold the scion in place.  Note where the nail is positioned.

I then lightly hammered the nails down so that the rubber portion is pressing the scion branch down into the stock branch.  Then I added a second nail to hold the other end of the scion branch down.  Once the scion was secured, I applied liquid cut paste to all exposed areas.  Graft finished!

Here’s Another Example

Again, I found another area that needs a new branch.  I used my saw and grafting knife to cut the groove in the stock branch.  In this picture, I placed the scion branch in the groove to check for fit.  The groove I cut ended up being a little bit too deep but it’s not a huge problem because deciduous trees in general callus easily and the scion and stock cambium will fuse together even it they aren’t exactly lined up.

Again I used two nailed to secure the scion to the stock.

Here’s a great shot of how only the green rubber portion is holding the scion down.  When hammering the nail down I needed to be careful to not applying too much pressure and crushing the scion branch.

I applied a liberal amount of liquid cut paste to seal all open wounds.  The cut paste is important because it will help seal in the moisture that is needed for callus to form quickly and easily.

After the I applied the cut paste, I then wired the scion branch with aluminum wire and put some movement on the branch.  After an approach graft is a good time to wire the branch as well because once the graft takes, the scion branch might be too thick to wire or put unnecessary stress on the graft union.  It would a shame to spend the time to graft, have it take, then kill the branch by applying wire to it.  Doing it now when everything is fresh is best.

Also note how short the internode between the graft union and the first node of the scion branch is.  We need to take into consideration the internode lengths when placing the graft because we don’t want to do all this work just to find out the grafted branch internode is too long later.

I continued to wire the rest of the branches and put some movement in them.  I cut many of the branches shorter on top because I didn’t need the branches to get much thicker there.  I left the bottom branches long because I need them to continue to thicken.  In 6-12 months I will revisit this tree and see if the grafts were a success!

For those have have these nifty nails to use for approach grafts, the left nail is the normal length and the right nail is a modified length.  Maple live wood can be very hard so driving a thin nail into it can be difficult.  Because of that, I took a old pair of concave cutters and slightly shortened them so that they can still be effective in holding the scion branch down but doesn’t require me to nail so deep into the heartwood.

Some of you might be wondering, “where can I find those nails with the rubber on them?”  Me and several people have tried finding these nail in the US with no luck.  They seem to only be available in Japan.  They are mainly used to nail boards onto a frame and come in various lengths and thickness.  For the time being, it looks like if we’re going to use these nails for approach grafting, we either have to make them ourselves import it from Japan.  If you the reader knows of a local place to get it, please share it with everybody in the comment section below.  You would be doing me and everybody else a favor!

Defoliating Maples

In Bonsai, we hear the word defoliate many times, especially with maples.  Defoliating a maple is pretty much the removal of all the leaves during the growing period.  Note how the Maple I just worked on was not defoliated.  Defoliation seems to be talked about so much that if people don’t defoliate their trees, they feel that they’re missing something very important when perhaps their tree doesn’t need it.  Though defoliation is a great technique when used properly, we have to realize when and when not to use it.  In my next post, I will talk more in depth about the concept of defoliation and the desired results of it.  In the mean time, think about the reasons for defoliation and when it should and should not be done.  Once you’ve pooled your thoughts together about defoliating, we’ll meet back here and I’ll share with you my thoughts on the technique and its uses.

In the next post, I’ll do some defoliation on this tree and show some examples of the many others that I’ve done in Aichien.  Do you remember this tree?

If not, this is what the tree looked like in the middle of last April.  Yes! It’s one of my project trees.  If you would like to know the story behind it, you can visit the original post about it by clicking Here.

Thanks for reading and see you soon!

P.S. If you are actively reading this blog, I would appreciate it if you subscribe to it (right column of the blog).  This is one of the best ways for me to know how many people are reading.  Thanks!

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24 thoughts on “Rebuilding a Japanese Maple

  1. Mary says:

    Very informative. Please add me to your news

  2. Mac says:

    Great job on both the Grafting and the posting. I am new to the Hobby and am trying to absorb all the information I can find. Both of yours that I have read are top notch. Good job. Incidentally, the window screen spline rubber that Stephen mentioned comes in several thicknesses, and Lowe’s sells it in a package of (I think) thee different thicknesses. Or you can get a Bulk length of it from a spool from them. It is reasonably priced and lasts for years.

  3. Steve Moore says:

    Thanks for the informative post, Peter. One thing I didn’t know was the importance of a hard surface for a callus to roll over. Useful to know!

    I used “zip ties” — nylon or plastic, sometimes called cable ties — on a recent graft, and they worked just fine.

  4. Stephen says:

    Guys, it’s much easier than you think. Just buy the rubber screening spline from any Home Depot or Lowes, or purchase it in bulk from Amazon. Then cut it to your desired length. Perhaps 1/4″? Then you can use whatever nails, tacks, brads that you like. Here’s a link to what I’m talking about:

    BTW, great article, Peter! I was just looking at my vigorous growing Red Maple and wondering how I could improve the branch structure. Thanks for giving me the idea and encouragement to try an approach graft. This will be my first attempt at grafting of any type. I’ll let you know how it turns out!

    • Peter Tea says:

      Hi Stephen,

      Thanks for sharing your suggestion! We can use all sorts of stuff to hold the scion branch down. Good luck with your grafts Stephen! Take care!

  5. Barry Dixon says:

    As usual Peter a fantastic look inside what you do ! I was wondering if those small cable nails electricians use to attach wire to timber would work to secure the graft
    They have a small plastic loop with a nail attached ,the wire goes into the loop which is open ended and you just nail it in …just a thought🙂
    And I to could not believe the amount of growth on that first Maple

  6. jeremiah lee says:

    Hey Peter, thanks for the post! I seem to remember hearing that these nails are made of stainless steel, however I could be incorrect. Do you feel the type of metal they are made of makes a differnce? Can the rust from a non stainless nail hurt the tree? I wonder if it’s possible to find stainless nails at a US hardware store. If so I bet you could find a plastic or rubber washer type thing, put the two together and bam! i’ll look into it.

    • Peter Tea says:

      Hi Jeremiah,

      That is a good question! Since I was able to cut the nail with my concave cutters, I don’t think it’s stainless steel but instead, some sort of coated steel. It seems a bit too soft for stainless. So far, whatever the material in the nail, it doesn’t seem to hurt the tree. Many times when the graft take, instead of pulling the nail out, we will just cut the rubber head off and leave the nail inside. So far, it doesn’t seem that rust does anything more then stain the area it is at. Perhaps it does something, but not enough that it becomes a real problem.

      There also is talk about how copper can kill a tree as well but I don’t really see that happening here. When creating root over rock trees, people will use copper to tie to the roots to the rock, then just let the roots grow around the copper. Many root over rocks in Japan, even the show ready ones actually have copper embedded in the tree. LOL

      I’m glad that you’re going to try and make something that will work. I’ve been to some nurseries here and found that they use only pushpins with no rubber. The type of push pins that are found in offices for cork boards. Hahaha. As long as it holds the scion branch down, it doesn’t seem to matter what we use.

      Thanks for the question Jeremiah! Take care.

  7. Penny Pawl says:

    Very enjoyable lesson. I keep trying different types of grafting and I like the idea of the nails really holding them in place. Penny

  8. Marty Weiser says:

    Another great post – I have been making my grafts too shallow. I use pushpins for bulletin boards for this type of work. They are very sharp and the base of the head is about 1/4″ in diameter. Pushing them through a small piece of rubber as CJ suggests would give the same overall results as the rubber headed nails Peter is using.

  9. Juan Andrade says:

    Hey Peter! Thanks for the informative post! Do you find any advantages to using the nails versus using some sort of tape to hold the grafted branch down? Or is just faster to nail them all when you´re grafting 10 trees a day😉 ?

    Thanks and take care!

    • Peter Tea says:

      Hi Juan,

      Yes, you can use other materials to tie the scion branch to the stock branch as well, though you will need to add a small pad onto of the scion branch just to make sure it sits tight against the stock branch.

      For instance, if the cut was too deep like the second graft I did, I would have needed to put something on top of the scion before tying to prevent it from moving around.

      At the end, the nail is just faster. LOL!

      Thanks Juan!

  10. Tabitha says:

    It is so amazing to see the growth that the tree had accumulated! It is genius work, what you do.🙂

  11. Mike Saul says:

    Peter: Please clarify. Did you search the maple for branches with the more desirable leaf then allow the scions to grow on those branches? I don’t understand how you got the desirable leaves on the tree in the first place. This was a very useful and well presented lesson, by the way!

    • Peter Tea says:

      Hi Mike,

      A few years ago Mr. Tanaka grafted all new branch to this tree and cut off all the old foliage except for one branch. Which is why I had to the example of old leaf to new leaf. He allowed the grafted branches in the past run for a couple of years to thicken then, then cut it back to grow all the small branches that I wired this time. There was some areas that still needed branches so I added 3 more grafts to the tree. Perhaps in the future, we’ll find that we need a few more and perform more grafts then. Good question Mike! I should have explained that a little bit better.

      Take care!

  12. ed curlee says:

    When is the optimum time to do the first, then second and then third (if necessary) defoilating. By month if possible please.

    • Peter Tea says:

      Hi Ed,

      I will explain the whole defoliating process in the next post. In the mean time, you can pretty much defoliate Trident Maples once the leaves harden off after each defoliation. On Japanese Maples, they can be partially defoliated but normally only once, maybe twice if it’s vigorous. Here we just partially defoliate once the Spring leaves harden off. Again, I’ll go into more details soon. Thanks Ed!

  13. Sandy Vee says:

    Thanks for another informative post! When is the graaf healed enough to be sepaaarated from the original tree?

    • Peter Tea says:

      Hi Sandy,

      Depending on how strong the tree and how well the graft is, it can be as little as three months during the growing season. Normally the time frame is 6-12 months for it to properly take. If the graft doesn’t take within 12 months, it’s time to try it again. Good questions and thanks!

  14. CJ says:

    I improvised by putting a 1/2 inch wood nail thru a small piece of car tires.

  15. cherylas2009 says:


    bring some of the fine tacks with plastic piece back with you and sell them. There are several of us who would buy them from you. I have considered making my own with small tacks and pieces from the jewelry kits you can buy but have not tried yet.

    Good post!

    • Peter Tea says:

      Hi Cheryl,

      I plan on bring a bunch of the rope, cut paste and these small nails in the future. I’ll leave some with Boon and the next time you see him, you can get it from him. Thanks!

  16. Juan says:

    Peter, I got mine at a Hardware store near Nagoya……… Juan

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