Antica Serra, Siena Botanical Garden

The cultivation of medicinal plants in Siena is documented from 1588 at the Santa Maria della Scala hospital; the university's botanical garden was instituted in 1784 by Biagio Bartalini at the request of the Grand Duke. In 1856 it moved to its present site in the Sant'Agostino valley, on land granted by the Accademia dei Fisiocritici.

It was during this phase of expansion, under the direction of Attilio Tassi, that many plants were introduced together with a heated greenhouse in iron and coloured glass: the Antica Serra, which the panels of the University Museum System date to 1875. The documents consulted name neither an architect nor a builder.

In the twentieth century the site gained a two-storey villa (1910-1912) for laboratories and the herbarium, then a tepidarium (1977) and a small limonaia restructured in 1996. The Antica Serra nevertheless remains the oldest and most historically and architecturally valuable building in the garden.

A requalification and energy-efficiency programme, backed by the Fondazione Monte dei Paschi di Siena (Let's Art), an internal university appeal (staff donating an hour of salary), the Rotary Club Siena, the City of Siena and the firm Pianigiani Rottami, lasted about a year and was presented on 4 December 2024.

The Antica Serra is a hothouse of about 85 m² with an iron frame and coloured glazing. Its entrance door is glazed in yellow and blue, and its masonry perimeter walls are entirely covered with Ficus pumila, a climbing shrub of tropical origin. It is designed to recreate the atmosphere of an equatorial forest.

The 2024 works concerned equipment rather than the historic envelope: the old gas heating was removed in favour of a high-efficiency, low-consumption electric heat pump connected to fan-coil convectors; an automatic shading system now protects the roof glazing from solar radiation; the display benches were refurbished to take more specimens.

The sources consulted do not give the height, the roof profile or the details of the metal framework.

The Antica Serra serves as the garden's equatorial house: it displays tropical and exotic species from around the world in the heat and humidity of a rainforest. The sources do not list the species on show. It also hosts seasonal thematic exhibitions and conferences, with an educational focus on exotic plants, their conservation and biodiversity.

Nearby, the tepidarium (350 m², built in 1977 and enlarged in the following years) holds tropical plants and plants of desert and semi-desert habitats; a small 38 m² limonaia keeps citrus trees and an experimental greenhouse serves research and propagation.

The 2.5-hectare garden holds more than 2,000 species, arranged in the Scuola (medicinal and food plants), the Parco, a rock garden, a fern slope created in 2000, aquatic habitats and the Podere, a small valley of heritage fruit trees, vines and olives. The herbarium preserves more than 95,000 specimens.

The greenhouse stands in the university botanical garden, at via P. A. Mattioli 4, inside Siena's city walls. The 2.5-hectare site occupies a sloping hillside of the Sant'Agostino valley and is crossed by accessible paths between flower beds, small ponds, woodland and rocky banks.

About an hour is enough to see the greenhouse, the tepidarium and the main sections. The seasonal exhibitions held in the Antica Serra give a further reason to visit; the fern slope and the Podere are most pleasant in the growing season. The garden combines easily with a walk through the historic centre, as it lies within the walls.