This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Climate change is causing many fruit trees to flower earlier, increasing their exposure to damaging late spring frosts. A study led by the University of Göttingen shows that the plant growth regulator ethephon can delay flowering in Kordia, a sweet cherry variety, potentially protecting blossoms and developing fruitlets from frost.
The treatment did not significantly delay flowering in a second sweet cherry variety or two apple varieties, highlighting the importance of crop and cultivar selection. The results are published in BMC Plant Biology. The researchers treated trees in commercial sweet cherry and apple orchards in Lower Saxony, Germany.
They tested two ethephon concentrations, applied either in early or late fall, and monitored flowering and fruit development during spring 2024. The study included 20 trees each of two sweet cherry varieties—Bellise and Kordia—and two apple varieties—Elstar and Kanzi. Flowering stage was recorded repeatedly on four marked branches per tree, with around 30 cherry flower buds and 15 apple flower buds per branch.
In the sweet cherry variety Kordia, 88% of flower buds on untreated trees were in bloom on April 9, compared with 56% after a high-dose early-fall treatment and 63% after a low-dose late-fall treatment. "Our results show that applying ethephon in fall can postpone flowering in some sweet cherry cultivars," says Dr. Wiebke Kämper at Göttingen University's Agroecology and Functional Agrobiodiversity Group.
"This could provide fruit growers with an additional tool for reducing the risk of frost damage." However, the response was not consistent: The treatment did not delay flowering in Bellise, Elstar or Kanzi. "Effects depend strongly on the crop and the variety, as well as the timing and concentration," Kämper explains. "We expected stronger effects in stone fruit than in apples, and the unusually early, warm spring of 2024 may have further limited our ability to detect differences.
Further trials across varieties, regions and years are needed before recommendations for practical use can be made." Anna Maria Geisthoff et al, Ethephon as a bloom-delaying agent for frost-sensitive tree crop flowers at risk from a changing climate, BMC Plant Biology (2026). DOI: 10.1186/s12870-026-09346-4 Bachelor's in mathematical biology, Master's in creative writing. Well-traveled with unique perspectives on science and language.
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