Glasshouses of the TU Delft Hortus Botanicus

The garden's history is tied to Gerrit van Iterson (1878-1972), a pupil of Beijerinck who championed "technical botany" as a university discipline. Professor of microscopic anatomy at the Delft Polytechnic School from 1907, he obtained land in the Wippolder in 1914, about three hectares. The Laboratory for Technical Botany, designed by J.A.W. Vrijman, was completed in 1917, the year the Cultuurtuin voor Technische Gewassen was created; the first hortulanus, E.H.J. Cunaeus, drew up the planting plan. Van Iterson asked which substances colour dye plants and which trees yield the best latex, and he needed glasshouses for tropical plants.

A glasshouse complex was built in 1922. The TU Delft history attributes it to a German firm named Gustave Röder. Van Iterson directed the garden until 1948. After the war, Indonesian independence shifted interest away from tropical agriculture; the herbarium passed to Leiden, and in the 1950s Professor P.A. Roelofsen oversaw the renovation of the glasshouses. The garden gradually became a place for free strolling, while a merger of institutions in the 1980s cost it its direct link with teaching.

The National Plant Collection Foundation (SNP) was founded in 1988, and a 1997 subsidy supported the preservation of academic heritage. The 1990s saw education and research activities revive.

According to the TU Delft history, the complex comprises six glazed structures designed by the German firm Röder: an east-west entrance house against which five perpendicular north-south houses are set. This comb-like layout allows, according to the same source, plants to be grown in a controlled climate. The largest, the Van Iterson house, is devoted to tropical plants; a small orangery at the front shelters tub plants in winter and hosts the summer exhibition.

The garden is organised in three parts: the glasshouses occupy the north, a tree garden with winding paths the south, and functional beds for research the west. The basic design is by T. Koeslag and Son. The sources consulted give neither the dimensions of the glasshouses nor their materials, and do not say whether they hold monument status.

In the large Van Iterson house grow banana, coffee and kapok; the subtropical section holds tea, cinnamon and camphor. These choices recall the original mission: coconut, oil palm, date palm, rice, sugar cane, tea, coffee and cinchona were studied here as economic plants. In the adjoining technical garden, visitors find plants that yield fragrances, dyes, flavours, fibres or pharmaceutical raw materials.

The orangery shelters tub plants in winter, cork oak, citrus, strelitzias and palms, which are set outdoors in summer. Part of the collection belongs to the National Plant Collection, and a large seed collection feeds an exchange network: in the early 1960s the garden exchanged with more than 500 botanical gardens and sent about 5,000 seeds a year. Research at Delft has included a method of extracting baccatin III from the common yew. Six dawn redwoods in the garden belong to the first generation brought to the Netherlands after the species was rediscovered in China.

The garden covers about 2.5 hectares behind the university buildings, along the Rijn-Schiekanaal, a fifteen-minute walk from the centre of Delft. The glasshouses are entered through an orange door and can be visited on a free route or with a guide; the garden also offers treasure hunts, workshops and exhibitions. Public access is seasonal, so the warmer months suit best, together with the orangery's summer exhibition. The visit combines easily with a stroll through Delft's historic centre or across the university campus.