Without real knowledge in Mexican architecture, I am only conjecturing here. The prominent place greenery enjoys in urban curating reminds me of the colonial Spanish courtyards. But maybe it is a reflection of their harmonious relationships with nature before the Spanish arrival. Aesthetically this perfect blending of greenery with concrete makes Mexico City an idyllically relaxing urban space.
The four pictures below gives us a sample taste of this tranquil urban space. The top left is a soviet style complex for workers built in the 70s, while revolutionary Mexican ideals were on a high tide. Today the complex is still in residential use. The trees were so grand that their shades cover the whole small square.
Top right is the famous statue of the lady of reform in the city center. I took this picture during the gay pride parade. The trees are not dwarfed at all by the shiny office buildings nearby, nor by the landmark statue.
Bottom left is the famous studio for the couple of Mexican icon artists, Diego Rivera and Frida Kahol. They had designed the cactuses around the house, demonstrating their pride for the iconic Mexican plant.
The bottom right is a corner of the UNAM contemporary art museum. It is famous in Mexico City for discovering many up-and-coming artists by first showing their work before fame caught up to them.