The plum tree is one of the most satisfactory fruit trees in cultivation, provided it is well managed, with attention to all aspects and therefore also pruning.
In the plum family, there are varieties of the European species, varieties of the Sino-Japanese species, and Syrian and wild varieties that still produce edible fruit. There are a few differences in size between these large groups, but fortunately there are many common criteria that we can address without going technically crazy, even in a mixed organic orchard.
The European plum tends to be bushy, with vertically growing branches, while many Sino-Japanese varieties have more open weeping vegetation. Both plum species bear fruit on toasts (branches about 15 to 20 centimeters long), on mixed branches, and in short fruit formations called “may clusters”, which are sometimes inserted into the branches. However, the European plum tends to produce clusters mainly in May, while the Sino-Japanese does so indiscriminately on all these types of branches, producing flowers and then abundant fruit. Therefore, generally speaking, the size of many Sino-Japanese plum varieties must be more intense than that of European plums and this is already a guideline in the differences between the two groups.
When pruning the plum tree
Some size rules
Important attention when cutting branches
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When pruning the plum tree
Pruning of the plum tree in full production is carried out in the dry winter and in the spring-summer season in the green. In winter, you could theoretically always prune, except in frost, but to be on the safe side, it is better to wait until the end of the cold season and check whether the frost is damaging the shoots. This helps us understand how much production load to leave based on what is actually present. In the south, where frosts are unlikely, waiting for the end of winter to prune takes on another meaning, linked to the possible fall of flower buds due to a lack of response to the needs of the cold. Also in this case, pruning will be based on the amount of flower buds that actually remain.
Cut branches. When pruning the plum tree, the ideal is to thin the fruiting branches, to avoid the phenomenon of alternation of production and to produce plum trees and plums of adequate size. Thinning out the branches means removing some at the base, where there are too many and too close together. In the choice, it is better to eliminate those that tend to go inward from the foliage and those that intersect with others. In Drupaceae, mixed branches can also be cut above the bud, but not one-year-old ones, as this would stimulate them to vegetate without giving production. These branches must be left whole, so that they in turn generate clusters of mayonnaise, toast and mixed branches. The following year, they can be pruned precisely in correspondence with these fruit-bearing formations.
Fruit thinning. In green, the practice of fruit thinning plays an important role for consistent production over time. Plants have such a hormonal mechanism that the floral differentiation of shoots for the next year is reduced in busy years. Thinning precisely prevents this alternation of production, provided it is done at the right time, that is, just before the stone hardens. The fruits are removed by hand after natural firmness, leaving one every 6-7 cm from the branch.
Suction cups and suction cups. In any season, suckers, which grow vertically from the back of the branches, and suckers if formed from rootstock are removed. Suckers are essential even in small plants, as these branches consume a lot of energy.
As with peach and apricot trees, the recommended form of cultivation for plum trees is in pots, in which the main trunk branches out 70-100 cm from the ground into three open branches covered with side branches. The plant raised in this way reaches a height of about 3 meters (variable according to the rootstock, which is generally vigorous), shows good lateral expansion and excellent interception of light inside the foliage. Achieving this conformation requires at least 3 years of careful brood size management from planting. During the reproductive phase, it is important to be careful when opening the branches, as plums present some risk of skimming.
Some size rules
To learn how to prune plum trees, it is good to always keep in mind the four main criteria which are the objectives of this pruning work.
- Shape retention. By size, we mean maintaining the desired shape. The first three or four years after planting are essential, but also later pruning will be needed to maintain the built form.
- Slimming to rebalance production. Another criterion is to ensure balanced production with vegetative development. Therefore, fruiting branches should be thinned and ventilated. Good ventilation of the foliage is also a prerequisite for its health.
- contains the dimension . No less important is the objective of containing the development of the plant: the three main branches that make up the pot must not exceed 3-4 meters in length. This allows for manageable plums for most interventions from the ground.
- Remove the dry. Finally, pruning is also used to remove dry branches, those affected by diseases or damaged by the wind. Diseased branches should be removed from the orchard and if possible burned, otherwise they become compost.
Cutting skills important when cutting branches
The maintenance of pruning tools is important, not only in their functionality, but also in their cleanliness. It is essential to disinfect the leaves when it is certain or even doubtful that certain plum trees have been affected by diseases. In this case, it is necessary to disinfect the tools when switching from diseased (or suspected disease) plants to healthy ones.
Cuts should be clean and made with determination, leaving no defibration in the wood. A small portion of wood should be left to help heal the cut. To avoid the accumulation of damaging standing water in the cut, it is also necessary to make oblique cuts just above a shoot. Also in this case, leave a small piece of branch above the bud, but not a long stump as this could rot.
It’s always good to finally remember not to cut too much. A vigorously pruned plant reacts with strong vegetation and the vegetative-productive balance is broken. It’s best to prune regularly from year to year, but don’t overdo it.