The soft size of the fruit trees.

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The ”  soft pruning  ” of fruit trees in contrast to “severe pruning” aims to respect the natural development of each tree. Thibaut tells you what principles he follows to cut by adapting to what he has in front of him.

The soft waist is first to observe.

In front of a tree, I observe: where does the light come from ? Which branches are weak because smothered by others? Which branches seem more vigorous despite the lack of light? 
Which tells me the vigor of each branch: the density of foliage , and the length of the most recent branch – distance between the end and the nearest branch. If it is less than 3 cm, the branch does not lie much, it will mostly fruit. If it is longer – up to 50 cm sometimes, I consider it a vigorous branch that favors lengthening.

Conclusion after observation of this old apple tree. There is nothing to do ! It may be tired because its branches are not long, but each branch is well lit. 

The soft waist is then to understand the tree in front of me.

  • Once I have observed, I am able to say which branches are:
    • dead and why.
    • poorly lit, and therefore have no future.
    • too vigorous and take all the energy to produce only wood and leaves – the typical case is the sucker that leaves under the grafting point.

I can also determine how each branch will stretch in the next spring: nothing magical in it, just look at the direction of the three highest buds of each branch. It is they who will elongate the most, causing the inhibition of those who are below.

Let’s observe the organization of the buds. The perpendiculars all round will make flowers then fruits. Those near the axis of the branch and lying down, will only make leaves and twigs. Those perpendicular and sharp … have not yet decided. 😉 

I first cut to help the tree.

After watching the tree, I know if he needs help.

The goal of the soft waist is to save her strength . I know what are the branches that will die for lack of light, so I remove them. It avoids feeding them nutrients, and provides more light to neighbors . Then, looking at the tallest buds on each branch and their axis, I choose which one I keep last depending on its orientation. I never keep a bud facing the inside of the tree or to another branch.

Then I can encourage you to make fruit.

The following is only for pips. Stone trees grow well on their own.

If a branch is weak, I keep it few buds, otherwise it will not be able to feed them all. Conversely on a vigorous branch I leave more buds. It’s weird, do you think … There is in fact a certain logic:

Bud fruit or wood?

Buds that receive a lot of light and are not inhibited by higher buds are the future of the plant. The tree must occupy this bright space in height before another plant comes to sting him! It therefore loses no time and grows as quickly as possible without wasting energy for the fruits. The top buds become woody buds. 
On the other hand, if a branch is less well placed , poorly lit, the tree “understands” that it is badly embarked in this zone. He prefers to form more fruitsand therefore potentially install a descendant further, rather than lie down to occupy an already competing volume. The buds become fruit buds.

What is the relationship with the length at which I size my branches?

On a long vigorous branch , since it receives a lot of light and energy, the buds of the bottom must be strongly inhibited to turn into fruit buds. To inhibit them, we must keep a lot of buds above them, and cut long .

On a lower branch less vigorous , no need to keep buds above, it is already quite inhibited. It will necessarily make fruit buds. The risk is rather that it does too much, and do not have the energy to feed them. So I cut short !

We do not make any size trigemma, then?

The size trigemma is the traditional size “three eyes”, the opposite of the size soft. It is a rigid principle , which plate on each tree the same size according to a subtle principle. In late winter, you keep only three buds on the terminal branches of pome fruit. And hop. 
It is also used to prune shrub roses, cousins ​​of apple and pear trees. 
You can immediately forget it, it is binding and not particularly productive. The purpose of this kind of size is to make some big fruits very impressive.

And the size Lorette, is it soft?

Some think that Lorette’s waist is a soft waist. Because some of the interventions are done just on the buds, in summer.

Only the pruning season begins in April by shortening all the stems by 20 cm on a plant previously forced to form a pyramid or palmette. It’s a complicated thing: an illustration, just for fun – and for garden geometry fans:

In conclusion: the interest of the tree is also my interest.

tree that I spares , that I do not force to fructify a lot by giving it an arbitrary form will give me back. It will receive fewer wood pests , keep its vigor longer, and adapt its shape according to its location and variety. Little more for the lazy gardener, he also asks for less work !

Why is it said that sap is rising?

For trees, it is often used as a metaphor for sap to “rise”, and favors the elongation of the highest buds. As if the sap was inflated with helium and stored in height 😉

This is partially inaccurate:

  • part of the phenomenon is due to growth hormones. A particular hormone, auxin is produced by each bud and is released in the evolved sap – the one that goes down to the roots. 
    Therefore, the lower the bud, the more auxin it receives from the higher buds. As this hormone is growth inhibitory , the low buds that receive a lot of auxin are more inhibited, they lengthen less quickly. They are more likely to form a flower and then a fruit.
  • the other hand is related to the light: the evaporation on the leaves causes a “suction” and the rise of the raw sap. So leaves that receive more light receive more raw sap, and have more nutrients to grow. But it is the influence of auxin and other hormones that decides whether this energy is used to form flowers or wood.

Dr. Kimberly Seltzer

Postdoctoral Scholar, UC Berkeley Research Assistant, MIT

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