The 'House for Trees' prototype buildings designed by Vietnamese studio Vo Trong Nghia Architects have been designed as a sustainable solution to the rapid urbanisation of Ho Chi Minh City. Each concrete box building incorporates a green roof structure which acts as 'pot plant holders' for the Banyan trees and deep soil. Infill housing doesn't get much greener than this!

Images courtesy of 

http://votrongnghia.com/projects/house-for-trees/