Cherry is the earliest deciduous fruit tree to mature in the north, and has always been known as "the first branch of spring fruit". At present, the cherry varieties cultivated in our area mainly include Chinese cherry and large cherry. Due to differences in growth habits, there are also differences in shaping and pruning. How to prune a cherry tree at each stage? Let me briefly talk about my personal experience.
Cherry pruning is divided into summer pruning, autumn pruning and winter pruning, with summer pruning and winter pruning being the main ones.
(1) Summer pruning
The purpose of summer pruning is to improve light conditions, reduce the ineffective growth of new shoots, and enable the tree to take shape early, bloom early, and bear fruit early. The main pruning methods include: removing buds, twisting branches, thinning branches, removing branches, topping, and super short cutting.
Removal of buds: During the leaf cluster stage, all competing buds on main branches, side branches, main trunks and near the large cutting openings, including strong branches and extended branches and cutting openings, are wiped out. Cut off double buds and leave single buds, stems, diseased and insect-infested branches, waste buds and long fruit branches that have not set fruit, etc. Tillers sprouting from the rootstock should be cut off as soon as possible. By removing sprouts and wiping buds, useless new shoots can be reduced, nutrients can be concentrated, and the remaining branches can develop fully, with full flower buds and leaf buds. Wiping and removing buds can improve the lighting conditions of the canopy, greatly reducing the workload of summer pruning and the wounds caused by summer pruning of branches.
Twisting branches: Mainly twisting branches with few branches or long branches in the main and side branches prone to sunburn. When the new shoots are semi-lignified, the competing branches near the main branches and extended side branches, as well as the strong and leggy branches and upright branches that have space to become side branches or large and medium fruiting branches, should be pruned.
Thinning branches: mainly thinning out the overly dense branches on the main side branches and fruiting branch groups from the base. The amount of thinning is controlled to be 1/3 of the number of new shoots in the thinned area. Do not thin out too many branches at one time.
Removing branches: Mainly by removing branches to change the growth direction of the 60 cm long lateral shoots with leggy characteristics during the high temperature period.
Topping: Topping can easily lead to too many secondary shoots and a closed crown. In current cultivation, except for the reshaping of saplings, which requires topping of main and side branches, the topping of new shoots is generally not recommended during summer pruning.
Ultra-short pruning: Before June, the long branches with space on the main side backbone branches can be left with 1 to 2 nodes at the base for ultra-short pruning, so that small and medium-sized fruit-bearing branch groups can be cultivated.
(2) Winter pruning
Winter pruning refers to pruning after the tree enters winter dormancy. The main methods are: short cutting, slow release, retraction, thinning, etc.
Thinning branches: Thinning branches from the base is called thinning, also known as pruning. Thinning branches can improve the ventilation conditions of the crown, reduce the density of branches in the crown, make the stored nutrients in the tree relatively concentrated, and promote the growth of new shoots. After thinning the branches, it will inhibit the part above the wound and promote it below the wound. Thinning out weak, diseased, leggy, overlapping, and densely packed useless branches that block light can promote the growth of the remaining branches.
Retraction: refers to the short cutting of perennial branches, also known as reduction. Retraction can centrally supply nutrients and water to the retained branches, promote the growth of lower branches, and is beneficial to the rejuvenation of the tree. Its function is to improve the light conditions in the crown, reduce the fruiting part, change the extension direction and angle of the extension branches, control the crown, and extend the fruiting life.
Short cutting: Cutting off a part of annual branches is called short cutting. There must be leaf buds left under the cut of the short branches. The function of pruning is to reduce the number of leaf buds and flower buds on the pruned branches, enhance the growth ability of the pruned branches to produce new shoots, reduce the number of branches, and enhance the branching ability. Light pruning: cut off less than 1/5 of the total length of the annual branches. The new shoots that will sprout next year will grow weakly, but the number of new shoots will be large. They are mostly used to cultivate medium, short, and bouquet-shaped fruit branches. Or lightly shorten strong fruit-bearing branches to increase the number of fruit and control the growth of new shoots. Medium-short cut: cut off 1/2 of the full length of the annual branches. There will be full buds under the cut. The new shoots that will sprout next year will have strong growth and a large number of strong new shoots. It is mostly used for pruning the extension branches of the main side branches. Heavy pruning: cut off 2/3~3/4 of the total length of annual branches. The buds under the cut will be less full, but the amount of pruning will be large. Therefore, the new shoots that will sprout next year will have stronger growth potential, but new shoots will not sprout. The number of shoots is small and it is mostly used for controlled pruning of strong branches. Extremely heavy pruning: cut off more than 5/6 of the total length of the annual branches, and the branches that will sprout next year will be weak. This pruning method is mostly used to cultivate fruiting branch groups with developing branches and leggy fruiting branches.
Long-term growth: Do not cut annual branches and allow them to grow naturally. Long-term planting of leggy fruiting branches or long fruiting branches with excessive growth potential can weaken the top advantage and promote the formation of medium and short fruiting branches. Long-term storage can retain the maximum number of buds on the branches and slow down the growth of new shoots in the next year.
(3) Autumn pruning
Autumn pruning is a necessary supplement to summer pruning and winter pruning. After entering autumn, the growth is basically at a semi-stop state, and the tree body is not sensitive to pruning. Cutting off the green tips of the current year's branches can save nutrients and promote the development of the branches themselves, flower buds and leaf buds; Dense branches should be thinned out appropriately, and leggy branches should be retracted by 1/3 to open the light path to promote the development and fullness of inner branches. Apply protective agent to large cuts to promote healing.
As the saying goes, it is difficult to grow delicious cherry trees. If you want to create good growing conditions for cherry trees so that they can produce beautiful fruits every year, pruning is a way to scientifically manage cherries and increase production and efficiency. Essential technologies play an increasingly critical role.
In general, small cherry trees should be pruned into a vase shape (spindle shape) to promote light and air circulation and allow air to fully disperse around the branches. After entering young adulthood, dead branches and infected parts should be cleaned up in time every year to ensure the health and strength of the tree. Specifically in pruning, the specific situation should also be distinguished and avoid applying mechanically. The main things to note are: First, the pruning method should be determined based on the characteristics of the variety, tree age, tree vigor, planting density, cultivation method, cultivation level, etc. In addition, pay attention to the reaction after pruning and make timely adjustments if problems are found. Second, when thinning branches, do not do too much at one time. When thinning is necessary, it should be done gradually year by year, and the right amount should be mastered at the right time to avoid being too hasty. When thinning out large branches, the wound should be smooth without leaving any stumps. The wound should be slanted or facing downwards. It is best not to cut it into an "upturned scar" and apply wound protectant after disinfecting the wound. Third, the twisting part should be carried out at the semi-lignified part of the new shoot. In addition, twisting should be done by hand and cannot be replaced by pliers. Using dirty, blunt pruners to clean foliage can expose them to disease. Make sure your scissors are sharp so you don't damage the branches when pruning. Be sure to disinfect your pruners before each trimming of your tree. Fourth, for some varieties such as chicken heart, short-handled purple, etc., topping will reduce the number and growth of developing branches and even form small old trees, so special attention should be paid.