Tree of God - How to control the spread

The Tree of Heaven is beautiful to look at, but it spreads quickly and uncontrollably. If you want to stop the spread, you have to be patient.

The tree of heaven brings many advantages to the hobby gardener. The bitter ash family from Asia makes few demands on their location or the substrate. The tree of heaven grows quickly, has attractive fragrant flowers and offers atmospheric autumn colours. However, it should not go unmentioned - the tree of heaven is a garden refugee. Not only does it grow quickly, it also spreads uncontrollably, literally suffocating other native plants.

Tree of gods is spreading rapidly

The seeds of the tree of heaven grow almost everywhere and if you look carefully for the trees, you will often discover them between paving stones and cracks in the wall. Although the trees of heaven are an attractive sight with their yellow-green flowers and clusters of red fruit, they are invasive plants that are among the top 100 of the "Black List". In the cities in particular, the trees are spreading rapidly and often displacing the conventional street trees.

Tip: Young trees are only partially hardy. Another consolation, urban trees have a passable life expectancy of 50 years.

Anyone who is thinking about planting a tree of heaven should be aware that its little tree will tower over it within a few months and grow up to 20 meters high. The allotment garden is therefore not the right place for the impressive plants. There should be enough space to give the tree a unique position. The ideal location is about 20 meters from buildings and walls.

Measures against the spread of the tree of heaven

Creating a root barrier
Removing seeds and shoots
Sawing off the tree

If you plant a young tree of heaven, you are giving the go-ahead for intensive growth. This is not only evident from the fact that the trees do not need three months to grow a meter high, there is also a lot going on hidden from our eyes. The roots form an extensive network close to the ground and have an effectdestructively on the neighboring plants.

❶ The most effective solution: applying a root barrier

A professional root barrier is a worthwhile investment and, in the long term, the most effective way to counteract the spread of the tree of heaven. A root barrier consists of a particularly stable material. This special geotextile does not let air or water through and withstands even the most severe frosts. Attach the root barrier in a ring around the roots of the tree of heaven. The easiest way to do this is at the planting stage.

Note: Root barriers can also be used later. However, this is then much more labor-intensive, since the roots have to be dug up first.

The geotextile is placed in the ground at an appropriate distance from the root ball and closed with a click strip.

Inserting a root barrier - step by step

Dig planting hole
Insert plant
Customize root lock

Close root lock
Fill substrate
Close planting hole

When planting a young tree, the planting hole should be dug to an appropriate size. In order for the plant to develop at all, you should give the roots some leeway. Do not set the root barrier too tight and allow about three times the distance of the root ball. Otherwise, a stable root network cannot be formed. If the roots are constricted in this way, the plant cannot spread and will wither.

❷ Courageous intervention - the removal of seeds and shoots

The seeds of the tree of heaven are carried away by the wind and germinate in almost every new location. To prevent this, you should take heart and remove the infructescence in autumn. Then the plant will appear less attractive in winter, but you won't have to dig up tons of young trees from the ground in the following year. If it has already sprouted, you should consistently remove all unwanted shoots from the ground. As the plants grow, it becomes increasingly difficult to dig up the trees.

Tip: The removed plants and plant parts should not be stored on the compost. To consistently prevent the tree from spreading, burn the removed shoots.

❸ If all else fails - saw off the tree of heaven

Anyone who was not aware of the joy of growth of the tree of heaven will soon no longer be good at the bitter ash plantto be available. The trees have grown too big and have already successfully pushed out neighboring plants? The only solution seems to be to simply saw off the tree. This also seems logical at first, but will prove to be ineffective in practice.

If you have sawed off the trunk of the tree of heaven, it only seems to help the plants to spread out. If no root barrier has been created, the roots can spread almost unhindered within a radius of up to 15 metres. Even the felling of the tree does not put a stop to this. If you only saw off the trunk, you will notice that all the more new shoots appear in the area mentioned. If you do not have the opportunity to completely remove the root, you can try to “tire” the tree. For this purpose, all new shoots are removed as quickly as possible. It will take some time for the tree to gradually lose its growth instinct and then stop altogether.

The methods of controlled spread with their advantages and disadvantages

Measure	Explanation
Remove seeds and shoots	The method proves to be laborious. If the seeds are not removed in time, they will be carried away by the wind.
Create root lock	The root barrier should already be in place when planting. Use a product from a specialist shop that really seems stable enough. Don't set the root barrier too tight, otherwise it will no plant can evolve.
Saw off the tree	Sawing off the trunk will not prevent the plant from spreading. The roots will continue to push out new shoots eagerly. Only if these shoots are consistently removed does this tire the tree and it will gradually stop growing - also at the roots.