PL
Trees and shrubs, native or alien, are the most significant part of spatial composition in gardens or parks. For this reason, knowledge of species composition and particularly development of species composition in the past represent an important starting point for maintenance, notably in historical gardens. A permanent part of the species composition in historical gardens consists of introduced species. Alien species offered new shapes, colours and textures, and they also fulfilled a desire for new and unknown things. The article will present the species composition of trees and shrubs in historical landscape parks in Bratislava: 1. Sad Janka Kráľa, 2. Horský Park, and 3. The Park v Rusovciach. Our research in these locations was compared with available data on the occurrence of alien species in the research work of different authors from 1968 to 2013. In addition to the development of the garden composition we evaluated the number of genera and species and also their biogeographical origin.