It has survived for 400 years – the oldest of Britain’s botanical gardens, a haven of medicinal plants and ancient trees enjoyed through the centuries by famous names such as JRR Tolkien and Lewis Carroll. Yet after the Oxford Botanic Garden’s anniversary today things may look substantially different in future, due to the impact of the climate crisis on British weather.
“We have to consider very carefully what we plant for the future,” said Prof Simon Hiscock, the garden’s director. “Particularly so with trees, because you have to think of not just a few years but in some cases hundreds of years ahead.
“We have reconfigured our rock garden to make it very much an eastern Mediterranean landscape.”
With temperatures reaching 30C last week, the purple delphiniums and huge yellow verbascums were busy with bees in the shimmering heat, Hiscock said. “It’s doing fantastically well at the moment with this blazing sunshine and heat, and the plants are just loving it.
“We also need to look at what is going to happen to our landscape as we become warmer. The Mediterranean garden is certainly easier to maintain than a normal English garden.”
There are also casualties. Modern roses and classic English herbaceous borders require substantial amounts of water, but the torrential downpours over the last few weeks had flattened many of the peonies, Hiscock said.
Domestic gardeners have been adapting to warmer conditions by buying fig and olive trees, but Hiscock said that the risk of diseases such as Xylella meant they should be cautious.
North American hickories such as the Carya tomentosa and the hop-hornbeam from southern Europe were interesting alternatives, he said, while the Persian silk tree and Persian ironwood were also beautiful.
Species like those were collected by one of the garden’s 18th century botanists, John Sibthorpe, who made expeditions to the eastern Mediterranean in 1784 and 1794, following in the footsteps of the ancient Greek physician Dioscorides, using his book De Materia Medica.
“Sibthorpe used that book to navigate his way around the eastern Mediterranean,” Hiscock said. The plants he found were sketched by Ferdinand Bauer and the specimens and collections formed the basis of the Flora Graeca, a book that the professor described as “the botanical crown jewel of Oxford”.
The founding stone of the garden was laid on 25 July 1621, because Henry Danvers, the first earl of Danby, had leased the five-acre site from Magdalen College to create a “physic garden” full of medicinal plants for teaching medical students.
“Students needed to be able to identify the plants that they would be grinding up for their medicines, and understand them. You can use atropine from deadly nightshade to good effect in small quantities, but high doses of course can kill people.”
By 1642, the garden was established and tended by the garden’s first keeper, Jacob Bobart the Elder, a German former mercenary.
During the English civil war, when Charles I held court in Oxford, Bobart began compiling a catalogue of the 1,600 plants in the garden, while selling fruit and vegetables from the garden and running a pub, the Greyhound. Some of the yew trees planted during this period are still standing.
By the 1830s, the physic garden was renamed the botanic garden, to reflect a growing focus on experimental botany, and is now home to 5,000 plants used for research, teaching and conservation. Authors Tolkien, Carroll, Evelyn Waugh, Philip Pullman and Colin Dexter have all made use of the garden’s tranquillity. The gardens also grow botanicals for use in its own brand of gin, and a whisky is due to be unveiled later this year as part of the 400th anniversary celebrations.
Today Oxford University’s chancellor, Chris Patten, will begin the commemoration by planting a handkerchief tree (Davidia involucrate), to go alongside the 350th anniversary tree planted by Harold Macmillan in 1971.
There will also be a new rose, the Oxford physic rose, created by Peter Beales and bred for its combination of hardiness and scent, although it is not as resilient as the damask roses that Sibthorpe identified.
Resilience was a quality gardeners were prizing more and more, said Mark Gush, head of environmental horticulture at the Royal Horticultural Society. “It’s about coping with extremes,” he said. “It’s not just about increasing temperatures – there could be severe cold snaps and extremes of water, drought and flooding. Broadly, people should think about whether the emphasis is on adaptation or on mitigating a changing climate.”
Some plants bred to create a classic English country garden might struggle, Gush said. Planting tree species that sequestered carbon could be an approach for those wanting to mitigate the climate crisis. Improving soil quality could also help.
“If you are improving the soil, its drainage capability, the amount of organic matter and nutrients, then you are automatically increasing the resilience of whatever tree or plant you’re establishing,” he said.
Resilience was key, Hiscock agreed. “Plants are far more fascinating than animals,” he said. “They are longer-lived and more durable. They withstand. If it gets hot, animals can move into the shade or go north. But plants sit there, and endure.”