Switzerland’s iconic cherry tree faces replacement as blooming speeds up

The cherry blossom season has begun. SRF

Ornamental cherry trees are blooming in cities. Now a legendary wild cherry tree in Liestal near Basel, whose flowering has helped farmers determine the exact timing of harvests for decades, is following suit. But it will soon have to be replaced.

Spring is currently bursting into life in many places. Almost overnight, the white and pink splendour of ornamental cherry blossoms can be seen everywhere. Town squares, parks and roadsides are briefly transformed into a sea of colour.

In contrast, the famous wild cherry tree on the edge of the forest near Liestal, in canton Basel Country, typically lags behind – but not for long.

That time has now come. “As of today, around a quarter of the blossoms have opened,” says Susanne Kaufmann from Liestal. The biologist is currently observing the tree daily with binoculars, tracking when the buds open and reporting her findings to MeteoSwiss, the national weather service.

How the story began

In 1894, Eduard Heinis began recording the blossoming dates of the wild “Weideli” cherry tree located on the edge of a forest near Liestal. The former teacher, government councillor and prison governor bought the Weideli farm above the Burghalde in Liestal. “He probably simply chose the tree that he could see through the kitchen window,” says biologist Susanne Kaufmann. He was thus able to work out when the cherry harvest began.

The wild cherry tree near Liestal is a legend. For decades, it has served as the official reference tree for the beginning of spring flowering.

According to biometeorologist Regula Gehrig from MeteoSwiss, climate change has clearly left its mark. In recent years, the tree has been flowering earlier and earlier – this year it’s two weeks ahead of the average over the last 131 years. That’s how far back the records go.

In Liestal, flowering has been documented since 1894 – forming a globally unique time series. Until the mid-20th century, this data helped farmers determine the precise timing of harvests.

“At the time, Swiss Federal Railways had to prepare locomotives, wagons and staff in advance. Shippers also needed baskets, lorries, labour and funds,” explains Kaufmann.

The old original tree was replaced in 1968 by a neighbouring cherry tree with identical blossoming dates. SRF

However, the much-celebrated tree is showing its age. “Although it still flowers regularly, it now looks terrible,” says Kaufmann. Its branches are breaking, and blooms appear only at the top of the crown.

In fact, this is no longer the original tree from 131 years ago. That tree died some time ago, and a younger neighbouring tree took its place. Since 1968, this “new” tree has supplied reliable data. But now it too is nearing the end of its life.

Successor sought once again

“Maybe it will be the cherry tree next door, which regularly blossoms one or two days later,” says Kaufmann, who is already monitoring it closely. Meanwhile, efforts are also underway to clone the current reference tree.

Last year, branches were cut from the crown using a lifting platform and grafted onto a young cherry tree. This process would preserve the genetic material of the current Liestal tree, and the cloned tree would be planted in the same location.

It remains unclear which of the two options will be chosen. According to Gehrig, the priority is to preserve the site at the edge of the forest. Nowhere else in the world is cherry tree flowering recorded in such detail and for such a long time.

Trees and bushes – the bloom is beginning earlier

“In general, everything in Switzerland has once again started to bloom much earlier this year,” says Regula Gehrig from MeteoSwiss. But it is not as extreme as the record year of 2024.

In addition to the cherry tree, which was seven days ahead of the average date from 1991 to 2020, plants such as the coltsfoot and wood anemone started spring around two weeks earlier than average.

“However, we had a lot of high fog in the Central Plateau this year, especially in February, which is why the catkins of the hazel, for example, were only ready ten days earlier than the average from 1991 to 2020 instead of 19 days last year,” explains Gehrig.

In general, however, all winter months were warmer than normal, which is a clear sign of climate change.

Translated from German using DeepL/amva