Show Houses (Schauhäuser) of the Stadtgärtnerei Zürich (Palmenhaus, Tropenhaus, Subtropenhaus)

Zurich's municipal nursery goes back to the nineteenth century and was originally on the Mythenquai, where the Sukkulenten-Sammlung stands today. It moved in 1941 to Albisrieden, on the Sackzelg: according to German Wikipedia's article on the city's parks department, the new building, in the style of classical modernism and decorated with a wall painting by Karla Götz, was designed by the architect Heinrich Weilenmann. The City of Zurich says the orangery was built in 1938 and was used to overwinter potted lemon trees and oleanders; the federal inventory of Swiss heritage sites (ISOS) dates the group 1940-1941 and 1961-1962. In the 1961 conversion the orangery received a glass pyramid roof and, together with the palm tower, became a show house open to the public; the Tropenhaus was built the same year, and the sand garden was laid out after the works of 1962.

Between 2012 and 2014 the complex, listed in the municipal inventory of objects worth protecting, was renovated at a cost of CHF 15.2 million according to the engineering firm APT, under Mischa Badertscher Architekten with Kolb Landschaftsarchitektur for the grounds. The Palmenhaus was fully renovated, the Tropenhaus received a new roof with a raised ridge, and a new Subtropenhaus replaced two greenhouses. The city now reports about 80,000 visitors a year.

The Palmenhaus combines the former orangery, capped by the glass pyramid, with the palm tower, which the ISOS inventory describes as a tall, tower-like, largely glazed palm house and a striking landmark despite the competition of nearby tower blocks. It rests on a fine concrete lattice structure, and keeping that structure, like the clean cubic form of the tower, was a requirement of the 2014 renovation. To cut heating costs the roof was insulated, the panes of the pyramid replaced and energy and shading screens installed beneath: strips of fabric unroll as the temperature drops, which the city says saves more than 30 % of energy during the heating season. Heating, shading and ventilation are run by a climate computer linked to a weather station on the roof. The neighbouring orangery kept its timber roof, backed inside by a new concrete slab.

The Tropenhaus received a new steel-and-glass roof in 2014, with a ridge raised by about a metre; the old steel frame remains as a trellis for climbing plants. The Subtropenhaus, a new steel-and-glass building based on a standardised construction system, replaces two greenhouses; its roof, a little over five metres high, can be opened, and the space is divided into two climate zones.

The Palmenhaus holds more than fifty tropical and subtropical species, mostly useful plants: coconut, kapok, baobab, rice and ylang-ylang, whose flowers give Chanel No. 5 its scent. Ten bird species from Africa, South America, Asia, Australia and the Philippines live there, among them zebra finches; the pond holds carp, koi, goldfish, platies and guppies, along with two species of North American pond turtle.

The Tropenhaus relies on humidity: a stream, pond and waterfall, passion flowers and jade vines on the old steel frame, orchids and ferns on a tufa wall, tillandsias and bromeliads on the trunks, anthuriums, medinillas, coffee and papaya. The Subtropenhaus, an annex of the Sukkulenten-Sammlung, is a working building with a public area: it shows drought-adapted plants from Madagascar, displayed in pots so that the highlights can change with the seasons. In the park the sand garden combines agaves, palms and desert grasses with sea sand; its potted plants spend the winter in the orangery.

The houses stand in Albisrieden, in the triangle formed by Gutstrasse, Sackzelg and Fellenbergstrasse, a few minutes' walk from the "Hubertus" tram stop. The park, the houses, the exhibition and the information foyer are open all year with no entrance fee; the paths inside the houses are narrow, prams stay outside and flash photography is discouraged in the Palmenhaus to spare the birds and fish. The sand garden can be visited from May to October, and the handkerchief tree in the park was planted in 1940. A seedling market is held in spring, and guided tours for groups can be booked. The production nursery itself is closed to the public. The Sukkulenten-Sammlung, of which the Subtropenhaus is an annex, has its own entry.