All Potted Up and No Place to Grow

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In a follow up to last month’s article on pruning, especially Japanese maples, I received a question from a member about putting shape to some maple seedlings. More specifically, is this a good time of year to do so? My answer is like many things in bonsai. Although this may not be the optimal time of year horticulturally speaking, it’s still a great time to create some movement in trees, so let’s talk about why.


When you have trees that move a lot of water through their systems, like Japanese maples, the structure that moves all of that water is on a larger scale than plants that move less water. That leads to them being both very rigid and very brittle. Contrast the maple with something like a juniper that moves resources very slowly. The size of the cells and tubes that the sap flows through a juniper are much smaller, so they are able to slip and adjust much more. Let’s just say for example that the juniper cells are an 1/8 inch long and I can bend each one 5 degrees without damage. In one inch I can bend it 8 times, or 40 degrees. Next we have the maple that has cells a ½ inch long. I can only bend it twice in that inch, or a mere 10 degrees. I can’t adjust my branch or trunk nearly as much. Some trees are more flexible just by their nature.

So, say I have a tray of seedlings or rooted cuttings. If I leave those grow for three or four years, it’s likely that they are just going to grow straight up. I am giving them proper health and nutrition and there is nothing that maximizes that more than growing straight up towards the light. But that doesn’t make very interesting bonsai material. So after five years of growing, I find that all of a sudden my maples have long internodes, are a ½ inch thick and are impossible to bend. My only option is to pray that there is a lower branch that can become a new leader, or prune the whole thing way down and hope that it back-buds. Either way, I have lost some valuable growing years. But curiously, the same situation arises with the Juniper. We already said that it’s more flexible, but what we didn’t talk about is strength. Even though the juniper can take a sharp bend, applying enough force to bend a ½ inch juniper in a short space is quite a feat and more than we can usually accomplish.

The better method for raising your own bonsai from an early stage is to bend them right away. The best time is when they are about an 1/8 inch in diameter, no matter how old or what the stage. With some pines, you might be able to take it up to a ¼ inch. You are probably not going to be able to bend them the first year, and it may be up until the third year that you can give them their best initial movement. 

When you do get to that first wiring, we have some things to talk about. First off, how tall you want the final tree to be? If you are working towards a shohin of about 8 inches and you want the trunk to bend three or four times, that means each one of your bends has to be about 2 inches apart. If you want a medium size tree, the curves will be larger and spaced farther apart. 

Starting these medium and larger trees are difficult, as you may not even have enough length to cover the whole trunk line the first go around. That’s OK. We have to start somewhere. Make sure that your movements vary in the length of intervals and angles to create an interesting shape that is interesting in all three dimensions. Also, we may end up with what started as a shohin growing into a larger size. We can make great use of those smaller movements in a larger tree to increase its quality. 

As we grow along, we may also re-evaluate our initial curves. We may look at a tree and say, you know, if I cut here, this will make a really great shohin. Or maybe this shape is not really that pleasing and if I cut here and make a new leader I can build in some taper and make a better shape. Nothing seems to go quite as planned in the life of our trees, so be opportunistic and take advantage of what each tree is offering you. 

The next thing that you need to know is to just let your tree grow. Let the leader and branch tips take off and grow, grow, grow. Remember, you have to grow some new wood in order for those curves to set, and to grow some girth on the trunk. If you wire in the winter, inspect them in April or May to see how they are doing. It may be the right time to remove the wire. If it’s a conifer, you can leave it a little longer, as any cutting in will likely disappear very quickly in the rough bark of the future. For thin barked species like maples, it’s a different story. Scars may visibly last for up to 20 years, so remove the wire before it cuts in too much. I have had many cases where I simply had to cut off the branch because the wire scars were too deep. 

Finally, another word about timing. Now is a great time to wire deciduous seedlings, when you can see their structure really easily. I want to caution about wiring mature maples this time of year and not to overlap the information too much. We talked about the brittleness of maples and it is easy to damage mature branches unknowingly this time of year. It may be better to wire them in early spring when they are in full swing and can repair any damage. The seedlings are more flexible and you have less invested in them. April and May are great times to wire seedlings too, especially when they have the new length of fleshy growth that has not quite lignified yet. It is easier to bend and it has all the rest of the growing season add tissue. The caveat of course, is that you have to work around the leaves. Here’s to some great new bonsai just around the bend.

Scott Elser