Equatorial Greenhouse, Jardin des plantes de Lille

The Jardin des plantes of Lille, inaugurated in 1948 on land of the former fortifications, is the work of the architect Jean Dubuisson and the landscape designer Jacques Marquis; it succeeds botanical gardens in Lille whose origins go back to 1596. Its layout, with its pools, peristyle, vases and statues, has been listed as a historic monument since 1 December 1997. An orangery was built there in 1952.

The Equatorial Greenhouse was built in 1969-1970 (Docomomo France gives 1968-1970) to the designs of the Lille architect Jean-Pierre Secq. It brought together, among others, plants collected by Lille explorers. Conceived at the outset as an exhibition greenhouse rather than for lasting tropical cultivation, it proved hard to maintain: structural disorders, crumbling concrete, cracked and clouded glazing.

In September 2022, amid the energy crisis, the city announced the closure of the greenhouse, effective in early October. The building was then described as the largest gas consumer among municipal buildings, with about 1.2 million kWh a year, roughly 225,000 euros according to one account. Docomomo France had filed a request for historic-monument protection in 2021; the building is not protected. It has since stood unused, and the city says it wants to study uses that preserve its architectural integrity.

The greenhouse rests on a reinforced-concrete base carried on three piers. The metal frame is covered with glazing, and cantilevered platforms create the effect of hanging gardens on the upper level. The flower-petal plan allowed the vegetation to be staged in a highly original way; slight inclinations of the floor slab create reliefs that form part of the experience of the route.

Docomomo sees a work marked by the research into kinetic art of its time, with volumes of complex geometry, and it has been compared, for its brutalist expression, to the conservatory of the Barbican Centre in London. The dimensions given by the city are 1,200 m² of floor and 12 metres high under glass (another source gives 8 metres). The materials themselves, concrete and metal without suitable insulation or ventilation, explain the difficulties: the building coped poorly with constant heat and humidity.

Until 2022 the house held about 2,000 plants representing 184 species, kept at a minimum of 24 °C and 80% humidity, with large specimens from every continent. It was originally conceived to bring together plants collected by Lille explorers.

On closure the collections were dispersed: tropical food plants (cassava, coffee, pepper, banana) moved to the neighbouring humid tropical greenhouse, about 1,000 plants were installed in the garden's conservation houses, duplicates were offered to other French botanical gardens, and about 1,000 common plants were entrusted to residents. Some large plants were the subject of propagation attempts.

The Equatorial Greenhouse has been closed to the public since October 2022 and cannot be visited, but it can be seen from outside in the Jardin des plantes, on rue du Jardin-des-Plantes in Lille. The garden remains open and covers about eleven hectares: botanical beds, a rose garden, a dahlia collection, a pond, and a neighbouring humid tropical greenhouse that took in part of the plants.

Allow an hour for the garden and its surroundings. The building's future depends on a renovation project not yet defined; it is best to ask the City of Lille before planning a visit.