These famous gardens are home to large hothouses full of tropical plants; a school of botany with 4 000 species of medicinal and edible plants; an ecological garden; an old arboretum where nature has re-exerted its influence to create an extraordinary reservoir of biodiversity; a rose garden; and an iris and perennial plant garden which is best visited in the month of May. The Cabinet d’Histoire displays etching, paintings and sculptures which retrace the history of these gardens.