Standing by the bush with a pruning shear in your hand, you probably sometimes feel nervous because you don’t know where you should cut off or just shorten this or that branch. You will become more confident when you answer the question: why do we prune plants?
Whether to make it bloom better or to make it not so big, not so dense, or maybe the opposite: to make it thicker as quickly as possible? Prunning can both reduce size and cause growth, so if you don’t want to get angry and harm the plant, think about it for a while.
Form young trees and shrubs
The vast majority of the plants that we plant in our gardens are small seedlings that need time and attention to develop harmoniously. In case of shrubs and ornamental trees, it is very important to cut the young shoots after planting so that the plant thickens. The real nightmare of beginner gardeners is to cut the newly purchased young bushes – you are happy with every twig, every flower and here you hear that you have to cut them and not just shorten them by a few centimeters, but practically cut them off, leaving some stumps! If you resist prunning young plants because you feel sorry for them, you need to know that the harder you cut the twigs, the more force the plant will want to rebuild itself. From the dormant buds that remain on the uncut parts of the twigs, many new shoots will grow quickly.
Why do we prune plants
- Let the light and air into the crown
- We form young trees and shrubs
- We stimulate or inhibit growth – depending on the prunning date
- We obtain colored shoots and leaves
- We remove winter damage and protect against diseases
- We keep a nice silhouette
- We encourage abundant flowering and fruiting
- We remove root offshoots and wild shoots
- We extend flowering
- We form green sculptures from plants
- We rejuvenate shrubs and trees
Before you grab a secateurs, know that plants planted in spring are cut right after planting, while those you plant during the season and in autumn are not cut until next year’s spring, as the wounds that remain after cutting may not heal before the arrival of frosts and the plant will be exposed to frost. Young shoots may also freeze, which the plant will release after summer pruning, because they won’t get enough wood for winter.
Prune the plants you bought with the bare root differently than those sold in pots. Those with naked roots (i.e. without earth and container) should have (apart from twigs) also the roots shortened, about 1/3 – of course shorten the roots before planting. Most often in this form are sold in spring and autumn popular shrubs such as: roses, forsythiae, ornamental cherries, willows, as well as cuttings for hedges, e.g. Ligustrum, hornbeam, beech, barberry. Before cutting, soak the roots in water so that the tissues of the plant are well watered. If you are planting in autumn, wait until spring with cutting the twigs, while in autumn shorten only the roots. Plants bought in full season containers should be cut only in spring of the following year.
Why do we prune plants? To stimulate or inhibit growth
By prunning, depending on when you do it, you can force the plant to shoot young or make it shoot less. The prunning in spring almost always results in a strong growth of the shoots, and this is because during this time, very intense juices (stored in the roots during the winter) that contain sugar and nutrients circulate in the plant. These juices reach the buds and give ‘building blocks’ for growth. If you cut the shoot, the same amount of juices will be delivered to fewer buds and this will make the shoots grow strong.
Prunning in summer has the opposite effect – you deprive the plant of excess shoots and leaves, so less nutrients will now be supplied to the roots for storage during the winter. This means that there will be less juice in spring, which is the ‘building block’ for the new shoots, so the plant will not grow as much. The strongest growth will be in the bud located directly under the cutting site, from the remaining buds smaller twigs will grow. Summer pruning is recommended in case of ornamental cherries, in order to protect them from a dangerous disease of these trees – brown rot of stone trees. In the summer we cut the glycine for the second time to stop the crazy growth of this climber.
Why do we prune plants? To keep a nice silhouette
Many trees and shrubs grow and thicken excessively over time, while shaving from the bottom, so annual pruning is necessary in their case. Such a cut is called a care, because it provides a good condition of the plant, a nice, compact habit and abundant flowering. It consists of removing the oldest branches, which are less blooming, as well as those growing inside and crossing and unruly shoots, which disturb the harmonious development of the crown. By doing so, you prolong the life of the plant, because after removing the oldest shoots, it will release new substitute shoots. This prunning is usually done in spring, but for shrubs blooming at this time of year, you need to be careful not to cut the twigs on which there are already flower buds, which will soon develop. That’s why we sometimes advise to do this cutting after flowering (among others forsythia, early tawny).
Why do we prune plants? To stimulate to abundant and longer flowering
There are shrubs, for example, roses and buds, which by removing blooming flowers develop new flower buds over and over again, which makes their flowering time longer. By prunning, we can also cause more abundant flowering. Some shrubs bloom the most abundantly on the shoots released this year – these we cut intensely in early spring (Caryopteris, cinnamon, summer tawny).
Other species produce the largest number of flowers on last year’s shoots – with cutting we must be very careful not to deprive ourselves of flowers and in their case we reach for the secateurs after flowering. But here too you have to be vigilant. Sometimes we cut only the blooming lilacs (lilacs) located on the tops of the shoots, and sometimes we shorten quite strongly covered with blooming shoots (forsythia, spring flowering tawels, Deutzia), so that the plant will produce young growths and manage to tie up the buds for next year.
It is therefore very important to check before cutting, what shoots the plant is blooming on and how it should be pruned to avoid making mistakes that could cost you a lot.
Note: There are species that bloom abundantly without prunning, such as witch hazel. When cutting them, be careful not to harm them.
Rejuvenate the bushes
Plants, like everything else that lives, get older with time: they start to bloom less, have fewer leaves, their shoots bald from below. To avoid this, you can remove all 1-3 oldest branches from the middle of the crown every year. However, if you have neglected to cut or don’t have the strength to do it every year, the old, dense bush can be radically rejuvenated by cutting all the shoots in spring quite short. Depending on the species and nature of growth, make this cut at a height of 10-30 cm above the ground. When the young shoots appear, cut the weak, rachitic twigs; leave only the strongest ones, of which you will start forming a renewed shrub next year.
Why do we prune plants? To obtain colored shoots and leaves.
We grow many plants because of the colorful shoots or leaves, for example the white dogwood ‘Sibirica Variegata’. The most beautifully colored are its young shoots and leaves, which appear on young twigs. If you want to have as many of them as possible, you have to cut your shrubs intensively.
Why do we prune plants? To let the light and air into the crown
Excessively thickened shrubs and trees are poorly blooming and bearing fruit. In the middle of such a crown there is a lot of suffocation, which favors the appearance of diseases and pests, for example, spider mite loves such conditions. Additionally, the leaves grow then only on the outer parts of the crown, it seems that there is a lot of them, but in the middle of the twigs are poor and bald. For this reason, the shrub or tree is not sufficiently nourished, as this number of leaves does not provide sufficient nutrient production. That’s why it’s worth cutting out all unnecessary shoots from inside.
A common mistake is to cut the crown twigs around the perimeter, which results in even more dense shoot tips and lack of light and air in the plant. If you really want to relieve the strain and light up the crown, you need to remove any unnecessary shoots from the center of the crown. You can do this in spring and summer (unless the species has a specific cutting date).
Remove winter damage and protect against diseases
In winter the plants are sometimes exposed to damage. At this time of year it is worth to walk around the garden from time to time to check if there is no need for intervention. It is generally advised not to make winter cuts in our climate, but sometimes when a large branch breaks down, there is no other way out, because such a wound is like an open door for all diseases and bacteria. You should then level the edge of the wound and apply garden ointment to it.
After the winter you should cut out all broken shoots, those with badly damaged bark and those that are frozen. During this time there are no leaves, so you can see any lesions on the bark – if you notice any disturbing symptoms, cut off the branch in the early spring, cutting into healthy tissue. This will stop the development of the disease. Sometimes during the season you also have to cut off sick branches, but first make sure what the plant is suffering from and whether cutting off will stop the disease from developing.
Remove root offshoots and wild shoots
In order to keep the plants in a good condition, the roots and shoots knocking out of the rootstock should be removed on an ongoing basis.
- Root offshoots in plants such as Siberian caragan, sea buckthorn, and Japanese marigold bush knock out the buds on their roots. If you do not want these plants to form a wild thicket, remove the offshoots regularly, and if you want the shrubs to form a dense hedge or a slope, leave them.
- The roots and shoots knocking out of the rootstock, on which the noble variety was grafted, are a more serious issue. In this case you cannot leave wild shoots. You must remove them as soon as they appear, because they can endanger the health and even life of the noble part. Such shoots often appear in grafted roses and decorative cherries. They can knock out of the ground, by the trunk or from the trunk itself (e.g. in trunk roses).
- In varieties with colored leaves, sometimes shoots with green leaves appear. If you notice such a branch, remove it quickly, because it’s the gene of the species which was heard in your plant (e.g. Fortune’s spindle with white-green leaves). If you don’t do it, it can drown out the ornamental variety.