The Botanic Gardens were originally designed as a teaching garden for students of Medicine. Covering a surface area of around a hectare and with approximately 650 plant species, the Utrecht medicinal garden at Sonnenborgh bastion was small compared to other botanic gardens in the Netherlands.
In 1723, the university purchased a larger and better site at Nieuwegracht. The accompanying garden was planted by botanic gardener Serrurier, using the plant system developed by Leiden University Professor Boerhaave. In 1726, it was followed by a heated greenhouse, fuelled by peat, for a collection of tropical plants. Despite its small size, the garden in Utrecht, in addition to its counterparts in Leiden and Amsterdam, played an important role in the development of systematic botany in the Netherlands.
In 1747 Professor Van Wachendorff, its director at that time, developed a plant system of his own, referred to as the 'Horti Ultraiectini Index', that was based on Linnaeus' system. In order to illustrate the relationship between the various plant groups, the garden facilities required expansion. Van Wachendorff's successor, Johann David Hahn, therefore built a large orangery on the north side of the complex in 1767. The lower floor was designed in such a way as to enable high-growing exotic trees, such as the large Utrecht Date Palm, to overwinter in the building.
The 20th century
In 1920, Utrecht University acquired Cantonspark in Baarn. From then on, the university owned two botanic gardens. The Utrecht Garden was called 'Hortus Botanicus', but in Baarn, the name Cantonspark was maintained. From 1964–1987, the Sandwijck estate in De Bilt was also home to a greenhouse collection that belonged to the Botanic Gardens. In 1987, this was moved, together with the collections from Cantonspark and the greenhouse collection from the Hortus at Nieuwegracht, to the new Tropical Greenhouses at the Utrecht Science Park location. These new greenhouses were built according to the very latest science, with computerised climate control in the various units. Many of the collections of perennial plants were also moved. However, the trees from the Hortus were too old to be moved. One example is the beautiful, old Ginkgo, planted in around 1730. It is probably the oldest example of this tree species outside Asia.
The former Hortus is now partly enclosed by the University Museum Utrecht. Visitors to the museum can admire this unique Gingko and other extraordinary trees in The Oude Hortus museum garden.