The spherical acacia is a decorative tree that impresses above all with its spherical crown. However, this is only a false acacia that belongs to the robinia family. With a total height of about two meters, a crown width of between four and five meters is achieved. But in order to give the spherical robinia its appearance and to maintain it, it needs regular pruning. Especially when there is not enough space for the expansive crown. So that everything is done correctly when cutting, the following article was created.
The right moment
When is the right time to cut the spherical acacia mainly depends on the cut made. So many hobby gardeners keep the cut in late winter until spring before the new shoot for ideal. Because if the spherical robinia is cut shortly before it buds, it quickly shines in its old glory. Under no circumstances should you prune after it has sprouted, because then it can happen that the tree looks "plucked" over the summer. But even in autumn, especially when the spherical acacia has suffered storm damage, it can be pruned. It is important to choose the right day:
- no expected frost
- especially important in late autumn
- overcast but dry
- when it rains, moisture can penetrate the interfaces
- this encourages bacteria or fungi
- the interface can burn in the sun
If the winter is very long and frosty or very wet, pruning should be avoided in the spring. Because even night frosts or a lot of rain can damage the tree at the interfaces and frost and moisture can penetrate here. This can quickly become an ideal breeding ground for bacteria, viruses or fungi.
Cut regularly
Regular pruning is important with the spherical locust. This is the only way to keep it in its spherical shape. But regular pruning is also important for the health of the tree. Because dead and damaged branches can also damage the entire plant. Over time, fungi will form here, which could then also fall back on the healthy branches. Therefore, the spherical acacia should receive a clearing cut once a year. If branches are damaged due to storms or frost, they can be cut several times a year.
Robinia pseudoacacia, black locust
Cut spherical acacia correctly: instructions
Regular cut
Regular thinning is important for the ball acacia. So it becomes inconspicuous, but also regularly rejuvenated. This is better than a radical pruning, which is not necessary with good care and regular pruning. If you cut the spherical robinia, you should always wear long clothes and especially gloves. Because the plant is poisonous in all parts and especially when cut back, the skin comes into contact with the poison. The regular cut is then proceeded as follows:
- remove any diseased or damaged branches
- cut right at the base
- Unfortunately, this can damage symmetry
- Crown is no longer spherical
- therefore also remove branches that disturb the visual balance
- also right at the base
- close big wounds
- then thin out the crown a little
It is better to work in pairs when cutting Robinia pseudoacacia to keep the spherical shape. So one person stands on the ladder and cuts, the other looks at the shape from a distance and gives instructions.
Thin out
If the tree has grown nicely without showing any damage, then you should only carefully cut the spherical acacia. Thinning out is important here so that branches and shoots inside do not interfere with each other and this could lead to competition. In such a case, the branches die off and the interior becomes bare. When thinning, you should pay attention to the following:
- Remove branches growing horizontally
- two branches take their place, cut one of them
- Prune shoots that grow in the wrong direction
- Cut at the base of the branch directly in front of the branch ring
- so the tree can close the wound against fungi and bacteria
- this applies to damaged and healthy branches
shorten
Especially when there are storms in autumn, the outer shoots of the crown of the spherical acacia can be affected. Then the crown should be shortened by about 2/3 in total. In this way, the robinia can form an even spherical shape again next year. In order to facilitate new growth, the shortening cut is always cut back to sleeping eyes. This is where the new shoots will appear during the next shoot.
Radical cutback
If the tree has been severely damaged due to a storm or other weather conditions, only a radical pruning can help. However, this should only be done in extreme emergencies. Because if you cut the spherical acacia radically, there is a risk that the tree will die. The following should therefore be observed with the radical pruning:
- always cut above a grafting point
- otherwise the spherical robinia will sprout below
- spherical shape is lost
- remove all damaged branches
- always cut below if a branch breaks
- otherwise too many bacteria get in
Robinia pseudoacacia 'Umbraculifera'
right tool
To ensure that Robinia pseudoacacia is not damaged when cut back, it is important to use the right tool. Garden shears or pruning shears can be used for light shoots. A pruning saw is ideal for thicker branches that have to be removed due to storm damage. To get to the crown, you can use a ladder. The tool also needs the following properties:
- clean and disinfected
- use pure alcohol from the pharmacy
- Disinfectant from the garden trade
- sharp
- fuzzy tool will damage the tree
If you work with unclean or fuzzy tools, this increases the risk of bacteria, fungi or viruses getting into the tree via the interface and causing massive damage to it from the inside.