How to stimulate back budding
Deciduous trees
In general, the problem that you notice is the absence of buds on ripened areas of the small branches. The buds are at the ends. What you want is to acquire buds on all parts of the tree, including the inner branches. Do that in spring so that the latent buds, located on naked wood, can open. To achieve this you will have to pinch the terminal buds just before they open completely.
What will occur? Well, being dry, the flow of sap will feed the remainder of the small branch and the latent buds. A number of them will open and this will increase the density of the ramification, because they will produce small branches. For deciduous trees that lose their leaves in winter, it is a technique complementary to defoliation. This latter technique is also used in June to promote back budding.
You can apply this method to trees that retain their leaves as well. But, take care; in all cases it is necessary to be sure of the strength of the tree and of the small branches pinched. If you don’t keep an eye on them you may not have a result — even death of the pinched small branch may occur.
The exact moment of pinching is critical. If the final bud is pinched when it has already developed, the sap will carry on its way and stimulate ramification only at the end. And so the effects of pinching will be much reduced and its result not very convincing. So, pinch when the bud swells, just before the small leaves start to become visible.
Once again, let’s reconsider the mystery of pruning small branches. Should they be pruned when green, or when lignified? In the first case the small branch is still in growth. It doesn’t have reserves and so, when it’s cut, growth is slowed down, budding will occur later and only at the tips In the second case, budding is carried out boldly at the end of the branches, and also back budding, because the small branch has accumulated reserves that will be utilised. For more density, it is better to be patient.
This pinching method is called ‘mekiri’.
If you wait too long, all the buds will be open. Before all the buds open, pinch out their heart with the fingertips leaving only two leaves.
Non-deciduous trees
It is essential that they are in good health and strong. Initially it is necessary to let the branches grow until they reach the desired thickness. This pinching will be done when the tree has an active period of growth. For example at the end of March, or in September. Be careful: do it before spring bursts forth.
First of all, with scissors, cut off the end of the small branch you want to make denser. Then thin out all the leaves except for the last two. These two leaves will make it possible for the stem to be fed by allowing the sap to flow. To thin out the leaves, with scissors cut off the leaves at the level of their petioles.
After10-15 days the petioles are desiccated and fall and, almost at once, small buds will appear at their base and open. Remember, in the first chapter of this book, we explained how the sap, which can no longer feed the leaves that were removed, goes to the latent and auxillary buds, which are then awakened and activated.
Moreover, two final buds will be formed and the small branch will be divided into two at its end. In conclusion, we started with one small branch. We now find ourselves with a branch on which there are as many small branches as there were leaves. It’s needless to say that, with all this new green and very active growth, the small branch will grow bigger very quickly. Do not forget either to spray to give it moisture and to give fertiliser once the leaves are mature.
Method suitable for:
- Olive
- Many Mediterranean trees
- Oaks
- Holly
- Most conifers.
Note
Never defoliate a small green branch, that’s not lignified. The latent buds will not have enough reserves to develop.
Junipers
When the strength of the tree is concentrated in the branches necessary to its health, it is the moment to think of their styling. In other words, when you have healthy branches, strong where needed, it’s wise to start modifying them. Indeed, these branches often have incorrect angles of exit from the trunk, or are too large to be curved.
Moreover, as one lets these branches grow, it’s possible that the ramification is too far from the trunk, leaving long bare segments. Remember that a bonsai must be compact with its foliage as close as possible to the trunk. You therefore benefit from the natural capabilities of the Chinese
or Sabina junipers to bud at the base of the branches. Prune the branches little by little to cause back budding so that this growth is
strengthened. When all that is done, cut off the old branch, and wire the new one to give it the desired shape. Take care that this new branch doesn’t grow only in length thereby losing its ramification.
General note on the seasons for pinching: The dates given are an average for France. Further north, you can always advance the late pinching by one month — at the end of August, for example, rather than the end of September for ‘mekiri’.
This branch was allowed to grow to increase the trunk. Now it should be styled. Indeed it is too long and the foliage is found at its end. This pinching method is called ‘mekiri’. It is carried out in July or, even better, at the end of September.
Fase 1
This growth leaves too
much space without
scales: remove it.
New buds shoot.
You will use them
to style the branch.
Prune little by little to pass strength to the new buds.
Fase 2
Allow to grow. Prune the old
branch when the new buds
are fairly strong.
Fase 3
Wire the branch while it is still green. Make sure that there are buds at the base of the new branch — this is very important.
Pines
Take special note of this section, because the pinching of pines is a mystery to many beginners. We are accustomed to distinguishing ‘strong’ and ‘weak’ pines. The strong ones react very well to cutting and pinching. The weak pines do not. They are slower to restart and there is even a risk of
them dying. The strong pines are the Japanese black pine (Pinus thunbergii) and our European Aleppo pine (Pinus halepensis). All the other
pines, therefore — Scots, mugo, five needle — are weak.
To back bud new candles they must be pinched once they have opened. Do this when the new needles are well set and formed. Two periods are possible for the ‘mekiri’: at the beginning of summer and, even better, in the autumn. Indeed, it is at this time that the tree accumulates a maximum of reserves and will be able to easily make new buds next spring.
On strong pines you can completely remove the new small branch by leaving two pairs of needles of the current year’s growth. On the weak pines, just cut back to a half or a third. Do not touch the very weak small branches. This technique is applied to young trees to develop their ramification, and also to mature trees that are to have their old branches remade.
Autumn pinching on pines with 5 needles, Scots, and mugo.
Tip
The method described here implies that the cultivation techniques are carried out without error, and that the trees are in ‘super good health’. Do not risk the tree if you are not sure of your capabilities. But rest reassured that if you pinch the candles in spring to balance the strength of the small branches, place it in the sun; spray it thoroughly and fertilise it well; it rewards you by back budding — less than with the ‘mekiri’, but in the correct manner all the same.
New budding and selection
Trees that retain their leaves
After the defoliation-pinching process seen on the preceding page, many buds will appear. This great quantity of buds will enable you to increase the density of the branches, but also, and this is most important, to renew their ramification. Indeed, before defoliation and pinching the small branch functioned with, say, 10 mature leaves; it will now function with 10 very new small branches whose very many small leaves will be
100% active. And so, this operation is very beneficial for the tree.
Moreover, the increase of branch density means that they will gain in diameter rather than adding too much length. This is exactly what we want when we try to create a bonsai. You will, of course, have far too many new small branches and have to make a selection. Remove those which grow upwards or downwards, that move towards the interior of the tree, and those opposite one another. You see, it is fairly simple and logical.
Before
After
Where there was only one small branch you now have 4 more of them. Even this is too much because they are opposite one another in pairs!
What about defoliation?
Non-deciduous leafy trees
If we don’t learn how to pinch to encourage back budding it will be impossible to increase the density of the tree without also increasing the length of the branches with strong growth. Indeed, beginners tend to simply cut off the ends of small branches. This will divide and produce two of them. The overall strength of the branch will be restricted to the two new small branches, which will grow in length.
In this way, the branch will continue to grow in length. The sap will go towards the ends of these two small branches forsaking the latent buds, which will remain inactive. As the branch lengthens, the foliage will all be at its end. The tree will be bare at the centre.
A great amount of auxins (hormones that inhibit the development of the latent buds, while increasing length) will be secreted from the tips of these terminal buds. For this reason, when you remove the terminal bud you can activate latent back budding. In this way the tree becomes denser and the foliage occupies all the available space near the trunk. This is the great principle of compaction.
Method suitable for:
- Olive
- Many Mediterranean trees
- Oaks
- Holly
- Most conifers.
