The spherical robinia gets its characteristic shape through appropriate cutting measures. We'll show you what they are and how to do them.
Robinia pseudoacacia 'Umbraculifera') are a sought-after focal point in the home garden. Due to their short growth height, the trees are also suitable for smaller gardens. As an undemanding plant, the spherical robinia requires little maintenance. With optimal care and the appropriate pruning measures, the spherical robinia forms its characteristic spherical crown. Below you can find out which pruning measures are recommended for the trees and how to proceed.
Tip: The spherical robinia differs from the conventional robinia not only because of its small growth height, the trees also have no thorns and do not flower.
Cutting Robinia
The spherical robinia should preferably be pruned in late winter or late autumn. When you use the scissors, the plant must not have sprouted freshly. A cut should also not be made when there is frost. If the thermometer falls, there is a risk that the branches will break when cut.
If the spherical locust is cut too late and the budding has already begun, the plant will bleed profusely, which means more plant sap will escape. This causes the plant to lose vital nutrients.
Tip: The spherical locust is preferably pruned in late winter so that the plant can regenerate sufficiently before new shoots appear in spring.
cutting measures
The trees grow quite quickly, especially in the initial phase, and can also be pruned slightly during the growing season if necessary, for example if branches are broken off and the shape of the crown suffers as a result. The spherical locust is also cut when it is infested with diseases or pests. Regardless of the season, all infected parts of the plant must be removed to prevent further outbreaks of the disease.
The following three editing actions can be performed:
- Clearing
- Shorten
- Pruning
➟Thinning Cut
If the tree has developed a rounded crown, is he althy and has grown well, a thinning cut is completely sufficient, because the spherical locust does not necessarily have to be pruned regularly.
How to proceed:
- cut smaller branches
- Cut directly at the base
- poss. Use wound sealant
When thinning out the crown, the hobby gardener only shortens smaller branches, which are damaged and affect the growth habit of the crown. Work directly at the base and remove the branches completely. No stubs from the shortened branches should remain on the trunk. You can also take this opportunity to remove he althy branch material if this affects the growth form of the spherical locust. Make sure the branches are evenly distributed to create an attractive overall picture.
The cut edges should be straight and clean. This can only be done with appropriately sharp knives or scissors. Frayed cut edges weaken the plant and make it vulnerable to diseases or pests. If larger wound areas have developed, you should use a wound closure agent.
➟ Shorten crown
If the crown is no longer spherical and you discover some damage in the crown area, the crown should be reshaped by shortening it. To do this, shorten the entire crown area by at least 2/3. Since the spherical locust tolerates pruning very well, it can also be shortened more if necessary.
How to proceed:
- Shorten branches by at least 2/3
- Rework crown shape
- possibly remove shoots afterwards
The pruning should always be done over a sleeping eye. This makes it easier for the plant to sprout again. If you shorten branches that have already reached a considerable size, these branches may sprout more after pruning. If this is the case, remove the shoots afterwards to promote the natural development of the crown shape.
➟ Radical Pruning
If the crown has lost its shape, whether through disease, windbreak, or years of neglected care, you should consider pruning it completely. However, the radical pruning is not without risk, because the tree could die.
How to proceed:
- Pruning back above graft
- leave some butts
- Remove shoots regularly
- Track formation of spherical shape
The pruning always has to be done above the grafting point. If this is neglected, the rootstock will sprout again. The desired spherical crown is then not formed. After budding, further pruning measures are necessary, because shoots that are too close together have to be removed so that the desired spherical shape of the crown forms again.
Overview of cutting measures
| cutting measure | Special Features |
|---|---|
| Clearing | When pruning, only old or diseased branches are removed. You should always cut back directly at the base. No stubs may be left over. |
| Shorten | In the case of minor damage in the crown area, we recommend shortening the shoots by at least 2/3. The tree can then sprout evenly again. Cutting back directly over dormant eyes promotes sprout. |
| Complete pruning | If the crown is permanently damaged, the tree should be pruned completely. It should always be pruned above the grafting point. If this point is injured, the robinia loses its spherical shape.After pruning, shoots that are too close together are regularly shortened so that the crown can develop. |
Pruning measures after damage or illness
If the spherical robinia are planted in particularly drafty corners in the garden, wind damage can often occur. The branches break and the typical crown shape is often lost. The hobby gardener decides for himself which of the described pruning measures are necessary based on the damage.
In the event of disease, all affected parts of the plant should be cut back radically. If possible, leave some strong and he althy branches. This encourages crown redesign.