When Is the Best Time to Prune a Pomegranate Tree Through the Four Seasons of Spring, Summer, Autumn and Winter, and How to Prune and Train It
Pomegranate, also known as shanliye, danruo, ruoliumu, jinying, jinpang, tulin and tianjiang, is a common fruit tree in Jiangsu, Henan and other places, and it is now grown in most parts of China. To achieve a high pomegranate yield, it needs to be pruned to promote the growth of side branches, so how should a pomegranate tree be pruned in spring, summer, autumn and winter? When is the best time to prune? How should it be pruned?
I. How should a pomegranate tree be pruned?
1. How should it be pruned in spring?
(1) Pruning time
It is carried out from after bud break to the bud stage before flowering, generally from mid-April to May, mainly from late April to late May.
(2) Pruning methods:
1) Adjusting the proportion of fruiting branches
Use scissors to cut away excessive small branches or fruiting mother branches so that the ratio of fruiting branches reaches a reasonable level.
2) Thinning buds and flowers
During the period from bud appearance to full bloom, all bell-shaped flower buds should be removed. For flowers that have already opened, only the bell-shaped flowers need to be removed, leaving the tubular flowers and normal gourd-shaped flowers, so as to avoid nutrients being absorbed. At the same time, around the fruiting branches bearing normal gourd-shaped flowers, 3 to 5 vegetative branches (with more than 100 leaves) should be provided as appropriate. Bud thinning should be carried out 2 to 3 times during the flowering period to increase the fruit-setting rate. Under normal circumstances, bud thinning and flower thinning can clearly increase the fruit-setting rate by 20 to 30%.
3) Thinning out diseased and pest-damaged branches
Cut away diseased branches, damaged branches and so on. Pruning can be carried out at the same time as bud thinning and flower thinning.
4) Removing buds and suckers
While thinning buds and flowers, densely growing young shoots and suckers and sprouting branches on the trunk and above and below the main branches can be cut away to facilitate ventilation and light penetration and better growth.
2. How should it be pruned in summer?
(1) Pruning time
It is carried out in June to July.
(2) Pruning methods
1. Fruit thinning
In early to mid-June (in the north), after the young fruits of the 1st to 2nd flush of flowers have set well, cut away the small fruit in double-fruit clusters, all diseased fruits, insect-damaged fruits and deformed fruits, and bury them deeply to prevent the spread of diseases and pests. Considering the three flushes of flowers and fruits, more first-flush fruits should be retained and second-flush fruits selected. Third-flush fruits are often very small and ripen late, and under normal circumstances all of them should be thinned out.
2. Branch thinning
Cut away all kinds of branches that are diseased or pest-damaged, densely growing or excessively vigorous. Generally, a pruning area reaching 10 to 15% of the projected area of the whole tree canopy is suitable. The main purpose is to ensure good ventilation and light penetration so that flower buds and fruits can grow better.
3. Opening the branch angle
If the main branches grow upright and the spacing between the main branches does not reach the standard of 80 to 100 cm, it is necessary to prop the three main branches open with wooden sticks or pull them apart with galvanized wire so that the canopy has good ventilation and light penetration.
3. How should it be pruned in autumn?
(1) Pruning time
Between August and October
(2) Pruning methods
1. Branch thinning
This is similar to the summer pruning method. Densely growing, excessively vigorous and diseased or pest-damaged branches need to be cut away so that the canopy is in a “three sparse, three dense” state. In addition, the cut-off remaining branches, diseased branches, remaining leaves and so on should be gathered, deeply buried or burned to reduce the spread of diseases and pests.
2. Root pruning after fruit harvest and before leaf fall
From mid-October to November, fruit trees can be pruned after fruit harvest and before leaf fall. Under normal circumstances, relatively dense side branches or diseased branches, remaining branches, remaining leaves and so on can be gathered and cut away to facilitate the growth of side branches and new roots and ensure sufficient nutrition in all respects.
4. How should it be pruned in winter?
(1) Pruning time
It is carried out after leaf fall and before bud break. In dry and cold areas, severe winter cold can easily cause freeze damage, so pruning can be carried out before bud break in spring.
(2) Pruning methods
1. Handling large branches
Large branches should be handled according to the principle of “three sparse, three dense”. The three main branches, as well as the side branches, should maintain a distance of 80 to 100 cm from one another so that small branches (branch groups) have space to grow. When the distance between main and side branches is small, the method of thinning out large branches or opening up large branches can be used so that the above standard for large-branch spacing is necessarily reached.
2. Handling small branches
After the spacing between main and side branches is opened up, thinning is used so that the distribution of small branches (large and small branch groups) on the canopy becomes sparse at the top and dense at the bottom, and sparse on the outside and dense on the inside. The density of small branches in the inner part of the canopy should be somewhat denser than that at the top and outside, but it must not be too dense. The requirement is that small branches do not cross each other, do not overlap each other, and leave some empty space. Leaving some empty space means leaving the space needed for new shoots to grow after bud break. For example, if an original small branch is 30 cm long, after thinning a space of 30 cm must still be left for its development. That is, small branches should not only not cross or overlap each other, but also maintain a space of 30 cm between them. Otherwise, the new shoots that emerge in spring and summer after bud break will severely cross and overlap, forming a “three dense” tree that is not ventilated or penetrated by light.
3. Handling fruiting mother branches
During and after thinning, flower buds and the fruiting mother branches bearing flower buds must be identified, so as to retain as many fruiting mother branches with flower buds as possible and keep 3 to 5 vegetative branches around them. If there are too many fruiting mother branches, some slender fruiting mother branches can be thinned out further, leaving thick and strong fruiting mother branches with plump flower buds, and the ratio of fruiting mother branches to vegetative branches should be roughly 1:5 to 15, or a larger ratio of 1:5 to 8. If the original tree branches are too dense and no flower buds or too few flower buds have formed, then it is enough to prune only to the extent that small branches do not cross each other, do not overlap each other, and leave some empty space. For these branches, the adjustment of the ratio of fruiting branches to vegetative branches can be left until new flower buds appear after bud break the following spring. After winter pruning, the retained fruiting branches and vegetative buds can obtain relatively concentrated root nutrients and promote the flower buds and a small number of vegetative buds that are in the process of differentiation to transform into flower buds and fruiting mother branches.
4. Handling diseased and pest-damaged branches
When carrying out winter pruning of pomegranate trees, all diseased and pest-damaged branches should be thinned out or cut off to reduce or eliminate sources of reinfection by diseases and pests.
II. How should a potted pomegranate tree be pruned?
Potted pomegranates should be pruned before bud break in spring by cutting away excess branches and irregular branches according to the shape already conceived in mind. Pruning of young seedlings is mainly tip pinching, usually carried out when they are above 10 cm in height. For dense new side branches, they can be cut off from the base. For excessively vigorous branches, repeated pinching can be used for shaping, while at the same time promoting the early formation of plump and well-filled side buds in the leaf axils, so as to store sufficient nutrients for new fruiting mother branches the following year. Dense needle-like short branches can be cut away.
Pruning precautions:
1. In spring, cut away dead branches, dead leaves, diseased branches, excessively vigorous branches, weak branches and so on that formed during the overwintering period, retain healthy branches and the crown shape, which helps the plant send out new branches, bloom more and bear more fruit. Pinch off the growing tips when the seedlings are 10 cm tall to promote branch growth and achieve a full crown width.
2. When pruning a pomegranate tree, attention should be paid to keeping outside branches rather than inside ones and keeping upright branches rather than horizontal ones, and the cut should be left facing outward.
3. The focus of pomegranate tree pruning should be excessively vigorous branches and suckers at the root crown, because excessively vigorous branches sprout from latent buds in the cortex of the trunk or large side main branches. They grow vigorously, growing upright or diagonally upward, but are not easy to differentiate flower buds and interfere with the tree shape. Root-crown suckers emerge from the underground root crown and grow faster than the canopy branches, but mostly only consume nutrients.