Established in 1963 in order to protect the Vistula River riparian forest, the Łęg na Kępie Nature Reserve in Puławy has an area of 4.71 ha. The reserve, partially phytocoenotic, i.e. containing plant communities, is located on the floodplain of the Vistula River. It features numerous species of local and introduced tree species. Among the non-native species are the Swamp Spanish Oaks, Cottonwoods, Canadian Poplars, and Eastern White Pines. The Łęg na Kępie Reserve can be seen from the lower garden of the Czartoryski Park and from the vicinity of the garden plots.