- Wettest and warmest winter on record set the scene for one of the best spring blossoms at Kew Gardens
- Temperature of 26.6C marked the hottest day of the year at the West London botanic garden as experts warn of a clear warming trend dating back to 1990s
- Botanic gardens like Kew are in a unique position to collect empirical data on the effects of climate change
- Snowdrops, daffodils and crocuses are now flowering several weeks earlier than in the past
Record-breaking rainfall over the winter paired with relatively warm temperatures has resulted in one of the most spectacular spring blossoms at Kew Gardens, horticulturists say.
The botanic garden in the heart of West London saw a third of its annual rainfall in the first six weeks of winter alone, leading to ‘condensed’ blooms of magnolias and cherry trees lining Kew’s avenues.
The start of spring has also seen peak temperatures 10C above the average for early April. And on Wednesday, 8th April, the mercury at Kew Gardens peaked at 26.6C, officially marking the UK’s warmest day of the year so far.
The result has been an explosion of colour at the UNESCO World Heritage Site, making it a must-see destination for anyone keen to experience spring blossoms.
However, Kew’s experts warn the underlying trends behind this seasonal kaleidoscope are evidence of the UK’s changing climate, supported by historic weather station data collected at Kew Gardens since the 1990s and beyond.
Thomas Freeth, Head of Living Collections Support at Kew, says: ‘The Gardens are looking truly amazing at the moment and that is because we have had an exceptionally wet winter, with all that rain soaking into the ground and nourishing the plants.
‘At the same time, we have had one of the warmest winters on record and once the weather turned from cloud to sun, all the spring blossoms got condensed, resulting in perhaps the best spring we have seen at Kew in a decade.
‘Unfortunately, when we look at our long term climatic trends, the data is telling us that even with all of that rainfall, it has been one of the warmest starts to the year on record, and that poses a long-term risk, particularly for the 11,000 trees on our site.’
Kew’s horticulturists are increasingly having to deal with the impacts of shifting weather patterns and extreme weather events, such as the heatwaves of 2022 when thermometers peaked above 40C. More than 400 trees were lost that year to drought, compared to the average annual loss of 30 trees.
Long-term modelling indicates London’s climate could resemble that of modern-day Barcelona by 2050, and further research indicates between 30% and 50% of Kew’s 11,000 trees will be at risk of being lost to climate change by 2090.
As outlined in Kew’s Landscape Succession Plan, some of the trees most at risk include iconic British species such as English oak (Quercus robur), common beech (Fagus sylvatica) and silver birch (Betula pendula).
Thomas Freeth says: ‘Everything has bloomed at once and the Gardens are looking magnificent, but we are already seeing signs of mechanical drought across the site and soon, we will start to see the physical signs of stress in our plants.
‘The good thing is though, that as a botanic garden we are well equipped to monitor these effects across a wide diversity of plant species. Our tree collection alone is comprised of 1,500 species, which is as many as can be found across the whole of the UK.
‘And so, we have the capability to closely monitor these species, see which do well, and based on our observations, provide evidence-based recommendations for making our urban forests across London more resilient through targeted species selection for planting.’
Kew’s research indicates plants from Mediterranean and steppe climates are performing better, whereas species historically collected in the moist, montane and cooler parts of the globe are struggling increasingly.
Besides trees, phenology data collected over the past 50 years also shows that plants such as snowdrops are now flowering several weeks earlier than they used to, with similar trends observed in daffodils and crocuses flowering in the weeks right after Christmas.
Bulbs in particular are extremely sensitive to rising temperatures, and with one of the world’s largest bulb collections housed at Kew, horticulturists are in a good position to monitor the plants and make empirical observations on the impacts of climate change.
Thomas Freeth adds: ‘Fundamentally, a tree planted tomorrow is a teenager by the centuries’ end. We must utilise the knowledge and expertise held by places like Kew to adapt our planting in our cities and gardens, so we are well prepared for the future’
NOTES TO EDITORS
About Kew Horticulture
Kew Horticulture is central to RBG Kew’s mission to help create a thriving planet for all, powered by plants and fungi. Over 150 horticulturists care for one of the world’s most diverse living collections across Kew Gardens and Wakehurst - collections that serve as a vital resource for education and support Kew’s global scientific and conservation work. Kew’s horticulturists play a critical role as we face the twin crises of climate change and biodiversity loss, safeguarding threatened taxa through ex situ programmes and trialling climate-resilient horticultural methods. Their work continually strengthens taxonomically and culturally significant landscapes under Kew’s stewardship. Working closely with scientists to cultivate research material, maintain reference collections, and support global partnerships focused on conservation and sustainable use, Kew’s horticulturists provide a vital interface between science and the 16,500 species that make up RBG Kew’s living collections.
We cannot save the planet without skilled horticulturists to care for plants, and through apprenticeships, diplomas, and specialist placements, Kew’s School of Horticulture offers an introduction to green careers. This practice-based education combines scientific foundations with technical skills, creating the experts who can safeguard the planet in rapidly changing conditions.