Even if the flowers and fruits of some trees have high ornamental value, such as Albizia Albizzia and Luanshu, it is not necessary to pay special attention to flower bud differentiation because they are easy to blossom and bear fruit, and pruning and shaping can be combined. (1) Deciduous trees. There are many such trees, mainly deciduous street trees and garden trees. The purpose of plastic pruning is to cultivate good trees and huge crowns.
A good tree should pay attention to the direction of cutting buds, and a huge crown should pay attention to the distribution of branches, so pruning is the most suitable when winter buds are obvious, that is, it is the most suitable tree for pruning in winter.
Due to the different climatic conditions in different regions, the specific pruning time in winter is long and short. Generally, as long as the weather is particularly cold, trees can be pruned after they enter the dormant period and before the sap flows out the next year. When is the best time to trim? It depends on the local cold degree and the lowest temperature. Winter pruning in temperate and sub-cold regions is best carried out in early spring when sprouting. On the one hand, freeze-drying incision should be avoided, leaving a dead pile. On the other hand, after pruning, plants began to sprout gradually. At this time, the physiological function in the tree is quite active, and nutrients are concentrated at the top of the branches with the flow of sap, so the wound can heal quickly. However, in cold areas, some vines and flowering shrubs that need cold protection before winter, such as grapes, roses, peonies, etc., should be pruned immediately after falling leaves in autumn, so as to cover the soil or grass.
Winter pruning in warm temperate regions can be carried out in the whole winter from defoliation to germination in the following spring. Although the wound can't heal immediately, it won't be frozen and drained.
Deciduous trees with vigorous growth, such as Platanus acerifolia and Ulmus pumila, often need pruning in the growing season in addition to pruning in winter, among which Platanus acerifolia is pruned in May-June and Ulmus pumila is pruned in July-August. In addition, there are some special situations that need attention: deciduous trees that are not cold-tolerant should be pruned as far as possible after the cold has passed and before the juice flows out, that is, in the late dormancy period, it is said to be late winter or early spring in season to prevent losses caused by cold when pruning wounds, such as Chongyang, Sapium sebiferum and Albizia Albizia; Deciduous trees with a large amount of bleeding should be pruned in time after falling leaves, that is, in the early stage of dormancy, that is, in late autumn or early winter in season, in order to prevent losses caused by excessive bleeding, such as grapes, kiwifruit, four-season flower trees, etc. Deciduous trees should be pruned as far as possible after the ornamental period of branches, which is said to be early spring, such as red sour branches; Deciduous tree species with ornamental leaves, whether young or old, should be pruned during dormancy, such as ginkgo biloba and red-leaf plum.
② Evergreen leafy trees. This kind of tree species is also very extensive, including evergreen conifers and evergreen broad-leaved trees.
In garden application, there are trees mainly street trees and garden trees, and there are also shrubs with various other planting methods.
Most evergreen leafy trees are suitable for pruning in the growing period, among which broadleaf shrubs are generally highly adaptable trees, and the pruning time is relatively random, which can be carried out in spring, summer and autumn, especially hedgerows and spherical trees, which are often pruned several times a year. Some broad-leaved trees, such as Cinnamomum camphora, heather and beech, are generally suitable for pruning in spring.
Conifers are generally suitable for pruning in spring and autumn because of their high fat content, and the effect in spring is better than that in autumn.