AusBonsai

Many bonsai beginners seem to fall in love with Japanese Maple and just have to have one.
Acer palmatum is an iconic Japanese tree and also an iconic bonsai species. They are relatively easy to grow but not so easy to maintain as bonsai.
A look at any bonsai show will show far more trident maples than Japanese maples on the show benches which is and indication of how easy the 2 species are to grow. Even in Japan, tridents outnumber Japanese maples both at the shows and on sales benches.
The reasons for this start to become obvious when you try developing Japanese maple bonsai. Everything seems to be going well until you notice that your trees are developing unsightly swollen areas on the trunk and at the ends of the branches. I've found that Japanese maples need top level pruning and trimming to keep them looking good long term.
Here are some photos that may explain what I mean better than words.
Japanese maple before. This one was pruned in winter and has had the new shoots pinched earlier this season. Typical JM response to pruning is to produce clusters of new shoots around where it was pruned
There are at least 7 shoots growing around this node at the top of the tree Here's another spot. You can already see that the end of the small branch is thicker than the rest. If all these shoots remain both those places will become even thicker where we really want thin tapering branches.
Excess Japanese maple shoots MUST be removed as early as possible in the growing season to reduce the chances of reverse taper developing.
This shows the top after pruning.
Note that I've left 3 shoots here. I'll need to come back in a few weeks and decide which one to remove next. I think the thicker vertical shoot may be a bit too thick for the apex but I need to see whether the smaller one behind it will start to grow before cutting back any further. The whole tree must be trimmed like this. Grant Bowie uses the term 2x2 pruning to describe this process.

The tree after pruning I'd welcome other comments and experiences about growing, developing, refining and maintaining Japanese maple bonsai

i agree Shibui, I absolutely love Japanese Maples, but i need to keep them in the corner of my eye and do a quick check on them every 2 weeks to stop the new shoots going "mad". I find when i ignore them for a month or two during spring and summer they just produce new shoots where you dont want them and then need to do a tidy up.....other than that they are easy to maintain and grow.

I've defoliated some of my advanced Japanese maples.
Many people think defoliation is used to reduce leaf size but I think it is far more important to allow light to reach the lower and inner shoots. All the outer leaves shade those inside and lower down and those shoots get weaker and eventually die. You can see that I've left leaves on the lowest an some of the weaker internal shoots. Hopefully this will encourage them to grow and get stronger while the rest of the tree recovers and grows new leaves.
As a bonus of defoliating the tree in mid summer I get to see where all the shoots are growing and can remove any that are too crowded or growing from the wrong places. I can also find new shoots with overly long internodes and cut them back. The shoots that grow to replace these should have shorter internodes. As the leaves came off I discovered a branch with wire. I had forgotten about this and by autumn it would probably have scarred the bark. Off with the wires as well. The extra shoots that grow when the tree grows new buds are also welcome to build ramification.
More ramification usually means the leaves can be a bit smaller so in a round about way defoliation can promote smaller leaves even though that's not my primary aim.

Defoliation is a useful technique but it is much more than smaller leaves

Great thread and posts Neil, very informative especially for beginners!

Hi Shibui

Great post, and helpful hints.

Is it to late to defoliate now if you live in Sydney. I was looking at one tree this afternoon thinking it would be good to defoliate it but thought it may be a bit late?

Mark

I have a few japanese maples that all i have done with them in the last few years is repot etc. Then this spring i attempted to wire the branches in place but the branches thickened so fast that the wire started to bite into the branches. Now the leaves on these branches are dis-coloured and droopy. no sure if it will recover but my point is that japanese maples are not the easiest to train.

Shibui, Should we use concave cutters to remove new growth so there is more hollow at the removal site or would this cause unsightly scarring?

Mark P: It is cooler down here and I've still got a few that I'll do if I get some time before the end of the month. Not sure when the cutoff date would be? Some trees that I pruned really late on year sprouted new shoots but did not lose leaves that winter. Went back to normal after that. Point being I think it is hard to kill maples simply by pruning or defoliating.

Sue: I use concave cutters for any twigs larger than about 4mm thick but I often just cut the branch with scissors leaving a short stub which will die back to the base. These dead stubs can be removed flush with concave cutters in winter when you can see them.
If you want new shoots to grow after pruning don't cut too close to the base of the twig or node where you want buds to grow. Leave a stub and clean up after the new shoots are growing strongly.

Keels: You are right about JM not being easy to maintain. Easy to grow but keeping taper and fine twigs needs good skills and discipline. Your trees have grown well to have wire bite in badly that fast your branch will survive. If not, another one should sprout nearby and you will be able to grow and even better branch because your skills are better now. In most species wire does not need to be on for more than a couple of months so everyone needs to check often and remove sooner.

Neil,

Your post on 13th January says ....."...I've found that Japanese Maples need top level pruning and trimming to keep them looking good long term..."

at the risk of asking the obvious could you elaborate a little on this.

John(JP)
CBS