Urban green spaces are increasingly becoming important places for biodiversity. The cultivation of alien plant species imported from distant regions of the world has been recognized as important component of urban vegetation. This study aims at assessing the woody plant wealth of urban green spaces in terms of density, richness and composition, and investigating resident’s views and attitudes related to their satisfaction by the current condition of the green areas. We recorded 96 plant species, from 77 genera and 38 families. Most represented families were Rosaceae (14 species) (18.18%), Cupressaceae (11 species) (14.28%) and Fabaceae (5 species) (6.49%). More specific, the results of this study showed that only 41.6% of trees were Greek native species and 58.4% were exotic. The most frequently occurred and abundant woody species were Platanus orientalis and Thuja orientalis (60%), and Ligustrum japonicum (N=588) and Thuja orientalis (N=258), respectively. The findings highlighted that piazzas exhibited the highest values of species richness and diversity indices were also preferred most by the visitors.