The Temperate House sits at the heart of the gardens, which was designated a UNESCO World Heritage site in 2003. The gardens are home to Kew Palace, once a home for King George III's large family. The British royal family enjoyed the gardens as a private paradise for almost a century before it opened as a public botanical garden in 1840.
Kew's purpose was always to house specimens from around the world so they could be studied, understood, and, as of recently, saved from extinction. That's where the Temperate House comes in.
In the 1840s, famed Victorian architect Decimus Burton was hired to build a glasshouse. He decided on state-of-the-art wrought iron to build the Palm House, which was such a success that Kew asked Burton to build another greenhouse, twice its size at 4,880 square meters (52,528 square feet), for a growing inventory of temperate, or mild-climate, plants.
The Temperate House, opened in 1863, was also built with a skeleton of fashionable wrought iron, which was flexible enough to be molded into large, beautiful expanses, yet strong enough to be the metal of choice for designers of railways and warships. The entrances are reminiscent of ancient Greek or Roman buildings, with toga-wearing statues and 144 Grecian urns atop columns. Like many of his contemporaries, Burton was inspired by the mid-Victorian obsession with classical architecture, with its pointed shapes, clean lines and the use of mythological figures.
Advances in cheap sheet glass-making also allowed architects like Burton to marry classical design with thousands of large panes, allowing in sunlight while adding innovations like specialist windows and ventilation to control temperatures. With this revolutionary design, and the addition of gangways that allowed visitors to stroll alongside the tops of trees, the Temperate House became a sensation.
Yet, over time, the glasshouse deteriorated. Erosion, water damage and ongoing repairs impaired the very job of the glasshouse: to provide an optimal climate for temperate plants. Kew decided patchwork repairs weren't enough and closed the Temperate House to undertake a complete renovation at the cost of $57 million, the biggest in Kew's long history, with the focus on restoring temperature and air control.
"The lack of ventilation was exacerbated by the loss, over the years, of features that aided ventilation: the blocking up of low level vents and the fixing of formerly opening clerestory windows," said lead architect Aimée Felton.
The length of the renovation allowed contractor ISG, who employed traditional masons, lead workers, joiners and lime plasterers on the project, to adhere to the aesthetics of Burton's original designs, found in Kew's archives. In all, 25,000 individual components were carefully removed, cleaned, repaired and reinstated, according to Matt Blowers, UK managing director for contractor ISG.
The revival of the Temperate House is crucial for ecosystems around the world. It's home to 1,500 different species from Africa, Australia, New Zealand, the Americas, Asia and the Pacific Islands, some extinct in the wild, some once thought lost.
The extremely rare plants include a South African cycad, which was discovered in 1895 and its now believed extinct in the wild. This plant is a male and Kew holds out hope of finding a female to propagate.
It shares its refurbished home with Dombeya mauritiana, a flowering plant thought extinct in the wild until found in the highlands of Mauritius in 2009. Kew's cutting is the only cultivated tree of its species in the world. Nearby is Taxus wallichiana, an endangered species of yew from Nepal, which is used in chemotherapy drugs.
"In contrast to their sumptuous, romantic surroundings, these plants present a stark message. Despite being the foundation of pretty much all life on earth, we are allowing them to fall prey to a variety of threats," said Kew's Carlos Magdalena, a botanical horticulturist. "When the last plant of a particular species dies out, what might it take with it? A new cure for cancer? Ebola?"
Visiting this summer will give tourists a view of the Temperate House perhaps not available since the 19th century.
"While the newly propagated plants reach maturity, we will have the opportunity to enjoy a full and unobstructed view of the incredible metal skeleton in all its glory," Felton said.
