The urban and sub urban green spaces are parts of social expectations and affective reactions that show the deep attachment of the population. Whatever shape they take, green spaces take part in the shaping the urban scenery and hence they contribute in life quality of the city. Their role is diverse-social, psychological, ecological, aesthetic, cultural and political. With an awareness raising trend, the well being of cities has seen another interest regained in what concerns the city green spaces. This study which concerns itself with the dynamic situation of urban and sub urban green spaces of Boussaada, Algeria and its position in the town management, is conducted through a diagnostic survey achieved under the city managers. The floristic inventory realized showed the existence of a great floristic diversity with an exceeding number of 12000 trees. In sum, 74 species distributed in 62 genres and 37 families. These were heterogeneously distributed through the urban construct, but globally concentrated in the north-east (33%) and to the southwest (32%).Due to the fast urban changes, this horticultural richness started to feel the danger coming from the urban environmental conditions. Hence, it receives multiple aggressions and difficulties (from uprooting, pollution and mechanical impairments, etc). The 90 questionnaires and the number of readings to urban directories in the route of realization (PDAU, POS) clearly show the new look to the city and to the place of trees in the city management. Hence, a coherent management of green spaces needs to be launched to give the city its beautiful scenery with the support of the sustainable development policy of the town.
