The sustainable city of the XXI century must be a city designed with consideration of environmental impact, inhabited by people dedicated to minimizing energy requirements, food and water and waste disposal, heat and pollution. Knowing these conditions, the landscape architects can provide clues to enable to discover alternative development options that will become the best overall result for the environment. It is the urban ecosystem, which focuses on the knowledge of how cities function as ecological environments, in order to develop sustainable approaches to problems and reduce the impact on both the streets and squares and in the suburbs of large cities.