Oldest intact glasshouse

Glasshouses used for botanical purposes have undergone many changes in design and materials since they first emerged in the 13th century. The structures made primarily of metal and glass that we are most familiar with as horticultural greenhouses today first emerged in the early 1800s. Given that such fragile structures invariably break or need extensive repairs makes it tricky to identify the oldest survivors, even when allowing for damaged parts to be replaced over time. One strong contender is the half-domed Palm House in the gardens of Nuffield Lodge (formerly Grove House) on the edge of Regent’s Park in London, UK. It was built c. 1824 by pioneering architect Decimus Burton (UK, 1800–81), who later devised the much-larger iconic glasshouses at Royal Botanic Gardens, Kew, though the earliest of these was not erected until the mid 1840s. The Palm House at Nuffield Lodge has been Grade II-listed by Historic England since 1981.

The earliest-known proto-greenhouses date back to ancient Rome; in the palace grounds (likely on the island of Capri) of Emperor Tiberius, who reigned from 14 to 27 CE, it’s documented that plants such as cucumbers were able to grow year-round owing to a structure known as a specularium, comprising moveable planting beds edged with stone walls and covered with a translucent mineral known as mica that protected plants from inclement weather but allowed sunlight to enter. More advanced so-called “active greenhouses”, which offer more refined control of the environmental conditions such as temperature and humidity, arose in Korea in the 1450s. These used innovative technology such as an ondol underfloor heating system, oil-covered translucent hanji paper on the inner walls and roof, and steam from boiling water in an adjacent furnace room to introduce moisture into the air.

Rudimentary attempts at preserving tender plants under more substantial glass structures date back as far as the 1200s in the gardens of the nobility in Italy, as exotic species began to be brought back by traders travelling to the Asian continent and beyond. In their most basic form, these were enlarged cold frame-like buildings that leant against sunny walls to over-winter cold-sensitive plants.

By the Renaissance, these simple greenhouses had become larger and more elaborate. At their most extreme, they evolved into grand orangeries built at stately homes and royal residences. The original conservatories, orangeries are essentially long galleries attached to the a large house (or a discreet garden building) made from stone or brick but fitted with underfloor heating and huge windows that allow copious sunlight to enter, providing the ideal conditions in colder climes for tropical and subtropical plants (including citrus fruits such as oranges, hence their name). Given their much sturdier construction, it’s not surprising that many early orangeries still survive across Europe; some notable examples can be found at the palaces of Versailles, near Paris in France (completed in 1686), Kensington in London, UK (completed in 1705) and Schönbrunn, near Vienna in Austria, completed in 1754.

There are several other surviving glasshouses that were built around the same time as the example at Nuffield Lodge. The impressive curvilinear Palm House (which comprises some 18,000 panes of flat glass) at Bicton Park Botanical Gardens in Budleigh Salterton, Devon, UK, opened c. 1825. Also constructed in 1825 was the Nash Conservatory, designed by Regency architect John Nash originally for the grounds of Buckingham Palace, then relocated 11 years later in 1836 to Royal Botanic Gardens, Kew, in south-west London, where it stands to this day; however, as a stone and glass structure, this arguably falls more into the category of an orangery.

The mid 19th century in the UK saw a proliferation of glasshouse building at botanical gardens on a much grander scale to accommodate the surge and public interest in exotic flora being collected from around the world as the British Empire expanded into new territories. Still-standing examples from this period can be found at sites such as Belfast Botanic Gardens (completed in 1840), the Palm House at Kew Gardens (built between 1844 and 1848), the Water Lily House at Oxford Botanic Garden (1850–51) and the Lily House (now Tropical House) at Birmingham Botanical Gardens (1852).