Petrova Street leads from the city center towards east. The street is known for its old town houses and their front gardens. However, in the recent years, the houses have been replaced with the new apartment buildings. The greenery in cities is of a big importance for the biological diversity. Plant groups and their landscape are chosen by the climate, landscape of the area, and also by the needs, time and finances of the front garden owners. Although, the landscaping of the front gardens is of a big importance for the city image, there aren't any defined regulations for it. The purpose of this thesis is to define the size and the function of the front gardens, to name the horticulture flora, to specify the classification of the plants, life forms and their life expectancy, the origin, and invasion of the plants. Furthermore, the purpose is to evaluate the landscape of the gardens, to recommend the measures for its preservation and how to increase its biological diversity. The research was made on 123 front gardens, that are placed on the North and South side of the Petrova Street. The gardens are divided into three groups: Type 1 - front gardens of the older row houses (1910.-1945.), Type 2 - front gardens of the newer row houses (1945.-1990.), Type 3 - front gardens of the detached houses. The research was made from March 2016. until the end of June 2016., and it showed that there is a greater number of plant groups in Type 2 front gardens on the North and South side of the Petrova Street. On the North side of the Type 2 gardens prevailed the perennial plants and geophytes, while on the Southside bushes, trees and wooden climbing plants have prevailed. The largest arable land was found on the North side of the Type 1 gardens and the smallest on its South side. The largest paved surface was found on the South side of the Type 1 gardens, and the smallest paved surface was found on the North side of Type 3 front gardens.