Is it still possible to transplant an old tree?

You can’t transplant an old tree – or can you? Technically, it is quite possible. But the question is whether it’s a good thing to do to him.

Moving is a risk for every tree. Younger specimens can handle the stress well, but for large, old trees, this can be their death sentence. It is all the more important to prepare the campaign well.

“A tree always adapts to the conditions of its long-standing location. It knows exactly which way the wind is blowing, where it can find water and where there are other trees,” says Christian Hönig, head of tree protection at the Bund for the environment. and nature conservation (BUND). “It exchanges information with its environment.”

The older the tree, the better it has adapted to its environment. And that makes it all the more difficult for him to move to a new place, whether in his own garden or elsewhere. Christoph Dirksen of the Bund Deutscher Baumschulen says: “For trees over 15 years old, it becomes difficult and time-consuming, but it is quite possible.”

Two to three year time frame

It is enough to dig up the tree and plant it somewhere else – but it will most certainly go wrong. It is therefore necessary to plan more than a few months in advance. “Large trees need a preparation period of two to three years,” says Michael Henze of the Federal Association for Garden, Landscaping and Sports Field Construction in Bad Honnef.

This preparation begins with pruning the roots and the crown. For older trees, it is advisable to repeat this operation over several growing seasons. For the youngest, it is enough to do this work in the growing season before the planned move.

Reduce the root system

To get the root ball in good condition for growth in the new location, dig a trench around it, cutting off excess roots. The outside edge of the ditch will match the later outside of the ball, Henze explains.

The ditch extends in depth to below the main root zone and is at least 20 centimeters wide. The outline should not be too narrow, as as much root mass as possible should be preserved. Expert Henze advises that the diameter of the root ball should be at least twelve times the diameter of the trunk.

When digging the trench, long, thin roots are inevitably cut, which extend far into the earth and supply the tree with nutrients. It is therefore important to then fill the gap around the root ball with a special substrate containing substances that promote rooting. And you need to water the ball regularly.

Promotes the growth of fine roots

Digging and cutting have one purpose: in the period following the measurement, the tree will form new fine roots on the root ball. It will also urgently need it later to grow in the new location. Michael Henze’s advice: “You should leave as much soil as possible so that many small roots can form.”

The principle of pruning the root ball to create new finer roots goes back to a method used in the nursery: the four-year formula. Trees that are expected to be larger at the time of sale are often moved by professionals in their early years.

“The plant stays in the same place for four years and grows there. After four years the tree is transplanted, then it grows for another four years, is moved again and so on – until it is sold and obtains its final place”, reports a nurseryman. Christopher Dirksen. This method promotes the formation of fine roots, and a tree grown in this way can grow well in virtually any location.

Reduce the crowns by a good half

But now back to the tree in your garden: part of the preparations for the season before the move includes cutting the crown. It is reduced by up to 50% – ideally when there are no leaves on the tree. You need to make sure that instead of many small cuts, fewer and larger cuts are made so that the tree does not suffer as much injury.

The movement of the wood must also take place outside the vegetation period and in no case when the tree is still bearing leaves or fruit. The good time is from November until the end of April at the latest. It is important that there is no frost.

“Such a large tree is very heavy and often cannot be moved without the help of machines”, explains Christian Hönig from BUND. “If a crane is used, the tree should not be tied down by the trunk, otherwise the bark may be crushed so much that it dies.”

Round spades are best used for large and heavy specimens, which have many gripping arms and can lift the whole rootball out of the ground. This prevents injury to the tree. To protect the root ball, it is advisable to wrap it in a jute bag during transport.

New location, old conditions

The new location should be as similar as possible to the old one in terms of soil conditions, prevailing wind direction and solar radiation. The planting pit should be large enough, about one and a half to two times larger than the root ball. “The rule of thumb is: 30 centimeters of space on all sides,” explains Michael Henze. “The depth should match the depth of the ball.”

Once the tree is in place, the pit can be filled with compost and loose soil. “Important: the tree should not be planted deeper than its old location,” says Christoph Dirksen. “Otherwise there is a risk of lack of oxygen and he could suffocate.”

Displaced trees still require special attention and care. In the beginning, for example, special care must be taken to ensure that the tree remains upright safely. If necessary, it must be supported by pegs. Otherwise, it will sway in the wind and the roots may tear off.

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