Under good care, all young trees tend to form profusely flower buds three or four years after being planted in the orchard. Cutting can hinder this process or delay it for several years.
One of the conditions for the formation of flower buds is the presence of fruit-bearing shoots characteristic of a given species or variety. In apple trees of the Mclntosh variety, these will be shoots, in the variety Jonathan – short shoots and moderately growing long shoots, in the cherry variety Lutówka - moderately growing long shoots. On uncut trees, such shoots form already in the second year after planting them in the orchard. They are formed in abundance even then, when we create conditions for intensive growth of trees in the orchard through abundant fertilization, proper soil cultivation or irrigation. The intensive growth caused by the above-mentioned factors does not prevent the formation of short shoots or slowly growing shoots, thus typical fruit bearing elements. If a young tree produces a dozen long shoots within a year or two, they have a lot of leaf buds in total. Next year, just 2 the 3 the buds on the shoot will turn back into long ones. The remaining buds turn into short shoots. The more buds, the more shoots, and the greater the potential for flower bud formation.
The situation is different when intensive tree growth is triggered by pruning. Cutting by inhibiting the formation of fruiting shoots prevents the formation of flower buds.
Young trees can be cut by shortening the shoots or removing them. Shoot shortening delays the formation of flower buds more slowly than shoot removal. If every shoot in the crown is shortened by 1/3 we act on each of them stimulating them to intensive growth. If, on the other hand, we remove 1/3 shoots, cutting them at the root, the left-over shoots will react to the cut to a lesser extent because the cutting action is local, limited to the treated shoots. The left shoots may develop short shoots and flower buds.
Table. The effect of cutting and shortening young apple shoots of Mclntosh cv. On the number of flower buds (according to A. Mica, M. Grochowska, A. Karaszewska)
| Cutting methods | The sum of flower buds on the tree formed in a sequence 5 years from planting | |
| apple trees growing strongly on A2 | dwarf apple trees on M26 | |
| Annual clipping 1/3 shoots | 261 | 267 |
| Annual shortening of shoots by 1/3 | 165 | 233 |
| Annual shortening of shoots by 2/3 | 54 | 238 |
| Not cut | 488 | 499 |
The greater the tendency of trees to create shoots, on which the fruit later forms, the less the effect of the cut on the formation of flower buds. Older trees create more fruit-bearing shoots than young trees. Hence, they can be cut quite strongly without the fear of significantly inhibiting the process of bud formation. The same is the case with trees grafted on dwarf rootstocks and with short-shoot mutants. They are prone to short-shoot formation and are less responsive to cutting than grafted trees on vigorous rootstocks. (table).
The number of flower buds on a tree depends not only on the presence of suitable fruit-bearing shoots, but also on the size of the crown. As we know from the previous section, cutting inhibits the growth of crowns. Cut trees are smaller and usually have fewer flower buds proportionally.
Thanks to numerous studies, we know now, that moderate shoot growth is necessary, so that flower buds can form on them. We also know, that an adequate supply of organic substances is necessary for this process (sugars, proteins and others), which are produced in the leaves and collected in the shoots. Shading the leaves or their damage by diseases or pests prevents the formation of buds.
Cutting, as already mentioned, can significantly reduce the leaf area on the tree and thus indirectly adversely affect the formation of flower buds.
You also need to add at the end, that almost every cut reduces the number of flower buds, which are already on the tree during cutting. For spring cutting, depending on the method of its implementation, declines since 10 into 30% flower buds.