Cutting is a controlled interference in the plant’s hormonal balance. By removing the tops of the shoots we change the proportions of auxins and cytokininsstimulating the development of side buds. The problem occurs when we remove the already formed flower buds along with the shoots.
Many deciduous shrubs set buds last summer. If you cut them in winter or early spring, you will remove exactly the parts where flowers were supposed to appear. The plant will recover and put out leaves, but it will not bloom during the season.
However, too late autumn pruning can stimulate the plant to grow young, soft growths. Such shoots do not have time to harden before frost, so they freeze easily. In subsequent years, the plants bloom less, are more susceptible to diseases and start slower in spring.
In winter or very early spring, after severe frosts have subsided, we prune plants flowering on this year’s shoots. In their case, flowers will appear on new growths grown after cutting. This group includes, among others:
- Buddleia davidii,
- bouquet hydrangea,
- bush hydrangea,
- Japanese meadowsweet.
Strong shortening of the shoots stimulates them to produce strong, flowering growths. If we do not prune them at all, they will become excessively dense and their inflorescences will be smaller.
Attention: not all hydrangeas react the same. Garden hydrangea blooms on last year’s shoots. After a strong spring cut, it certainly will not bloom.
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Early spring is also the time for the so-called sanitary pruning in most deciduous shrubs. Removing dry, diseased, broken and frozen shoots improves their aesthetics and reduces the risk of fungal and bacterial infections. We make cuts in a dry day, with temperatures above zerosharp and disinfected tool.
The most common mistake concerns spring-blooming shrubs. They form buds on last year’s shoots, so they are cut only after flowering. This group includes, among others:
- Forsythia intermediate,
- Common lilac (lilac),
- fragrant jasmine,
- Three-lobed tonsil.
Their spectacular spring flowering is the result of the work done in the previous year. If we shorten the shoots in winter, the plant will rebuild its crown, but it will no longer bloom in a given season.
After flowering is finished the bush still has enough time to produce new growthwhich will become woody, mature and set buds for the next year. Cutting too late, in the middle of summer, shortens this period and may weaken the intensity of next year’s flowering.
After flowering, we remove them faded shoots above strong branching, shorten too long growths, and above all, overexpose the interior of the bush. Access to light and air has a direct impact on the condition of the plant and the quality of flower buds.
In older, overgrown specimens, it is worth using a rejuvenating cut. It involves systematic, spread over 2-3 seasonsremoving the oldest, woody shoots close to the ground. In this way, we will maintain the continuity of flowering and at the same time gradually rebuild the young, strong structure of the bush. A one-time, radical cut may have the opposite effect: weaken the plant and limit flowering even for several seasons.
Spring is also the time for correction of the shape of hedges and ornamental shrubse.g. from privet or dogwood. Removing shoots growing to the center of the crown improves air circulation and reduces the risk of fungal diseases.
Pruning is also done during this period large-flowered and border roseswhich bloom on new shoots. Cutting too early, at unstable temperatures, exposes cutting wounds to freezing. Too late delays flowering.
Early spring is the moment of a sudden start of vegetation for many plants. At this time, juice begins to circulate intensively in the tissues, transporting water and nutrients from roots to buds. In some species, pruning during this period leads to a phenomenon known as “plant crying”, i.e. strong, long-lasting leakage of sap from the cut site. Particularly sensitive are, among others:
- Norway maple,
- silver birch,
- True vine.
In their case, cutting done at the end of winter or just before the start of vegetation may result abundant flow of juices, which lasts for many days. Although the phenomenon itself rarely leads to the death of the plant, it significantly weakens it, prolongs the wound healing process and increases susceptibility to infections.
The pruners should be put aside until the sap circulation has stopped or has already started. The safest term is late summer, after the end of intensive growth or very early winterbefore the plant enters the pre-spring activation phase.
