Unfortunately, we live in a greedy little world and horizontal areas are often too expensive to leave to nature on them. Therefore, creating gardens on vertical surfaces of urban areas has recently been very important to supporting sustainability because these surfaces are still found to be commercially useless compared with green areas which are generally under pressure from commercial demands and politics. However, these artificial vertical green surfaces are still too far from being common, while too many ordinary walls are spontaneously covered with vegetation already. In this study, we try to address the dynamics of wall vegetation as it has a great potential to make the cities more sustainable. Totally 70 walls (35 in urban and 35 in sub-urban areas) in Trabzon city were examined regarding their ecological, physical and vegetation characteristics. Having identified 1540 plant samples collected from the walls during a year-round intensive field study, we performed statistical analyzes to enumerate the wall vegetation depending on the ecological characteristics; to evaluate if there are different wall vegetation compositions in urban and sub-urban areas; and finally to evaluate growth conditions and basic challenges for the wall vegetation.