The Botanical Garden of Rennes exists in the Parc du Thabor since the 18th century. Initially placed in front of the greenhouses and orangeries, it was installed in its current location, further east and with a centred plan, in 1868 by the landscape architect Denis Bühler during the total redesign of the Parc du Thabor.
The original role of this botanical garden was educational, aimed at students of botany, horticulture and pharmacy, hence the name École de botanique (School of Botany) which was often given in France to this ancient type of botanical garden, including this one. The Rennes Faculty of Science remained for a long time very close to the Parc du Thabor, to the south on the banks of the Vilaine river.
Since then, this botanical garden has retained its original layout of concentric ring-shaped beds with a central pool and cross-shaped paths oriented to the points of the compass. This type of centred layout can be found in the botanical garden of the Parc de la Tête d’Or in Lyon (France), another work (1857) by the Bühler brothers.
The natural entrance to the garden, because it opens onto the rest of the park, is its western entrance. It is therefore logically from this one that the start of the ring route was set, in a clockwise direction, from the periphery towards the centre.
The arrangement of the families adopted initially followed the ancient classification of Jussieu (in Genera Plantarum 1789) refined and completed by De Candolle. The various groups were (and still are) arranged as follows, from the outside in: Acotyledons (ferns and related) then Monocotyledons then Dicotyledons and finally Gymnosperms (conifers and related) in the centre because of their mainly arborescent habit. Similarly, among the Dicotyledons, the mainly arborescent families (Fagaceae...) have been moved closer to the centre in order not to overshadow the lower plants.
This traditional classification is still globally respected today but, over the existence of this garden, the evolutions and rearrangements of the collections have led to some oddities in the classification with some families now split in several different places in the garden (Lamiaceae, Oleaceae...).