Spring plants bloom a month earlier due to high temperatures

Spring plants start to bloom one month earlier one month earlier than 50 years ago, natural scientists Arnold van Vliet and Wichertje Bron from Natuurkalender and Wageningen University and Letty de Weger from LUMC wrote in the scientific journal Nature Today. Plants such as spearwort, yellow dogwood, snowdrops and crocus are already in full bloom.

"The yellow dogwood is a good example of the change in flowering season. 50 years ago, the first small yellow flowers only opened around March 13. In this century, the first flowering of the special spring plants can be observed on February 18," the researchers wrote.

The timing of the blooming is also linked to the temperatures in December and January. The warmer the first two winter months, the earlier the blooming date. The warmest December and January were measured in 2016. At that time, the average temperature was 7.6 degrees. Last December and January, the average temperature was 5.4 degrees. The average temperature in these two winter months between 2001 and 2023 was 4.2 degrees.

Van Vliet reported at the end of December last year that the hazelnut trees were already in bloom due to the warmth of the winter. The alders have also flowered heavily in recent days. This releases pollen into the air, which can lead to hay fever in dry weather.