Urban vegetation in Algiers, Marrakech, Antananarivo and Toliara is a pre-colonial, colonial and post-colonial heritage. The functions of refreshment, aesthetics and landscaping during the colonial period aimed at creating a pleasant and reassuring living environment for europeans. The choice of species and their spatial arrangement are part of a colonial urban model found in the four cities. Nowadays this colonial green heritage is in poor condition reflecting its inadequacy to their respective social and cultural contexts. However, urban plants provide services which are recognized in Northern countries but only very recently in Southern cities where they should fit to their stakes and contexts (heat, pollution, urban growth, poverty, heritage). During the colonial period, the plants as territory markers also had domination functions. Now they act as socio-spatial segregation, creating a dual town where urban vegetation played a role in the "hygienist" dimension of the colonial urban model. [ABSTRACT FROM AUTHOR]