The first botanical garden in Karlovac was arranged by the grammar school at Rakovac and it was established in 1870. Some particular tree species of this garden are preserved. In 1896 a new botanical garden was established by the mayor Josip Vrbanic. It was proclaimed by the Republic Institute for Protection in Zagreb for a horticultural monument because of its horticultural values. It was on 30 December 1970.
As a natural prolongation of that botanic garden on the ex Vunsko Pole in 1958, it was got some soil from the town for arranging a new botanical garden which was given a name by the known naturalist Ljudevit Rossi. Its plan was made by Mira Halanbek-Wenzler from Zagreb. In the period from 1965 till 1968 were planted 66 species of dendrologic material.