Rapid urbanization over the past five decades has led to environmental issues like air pollution, urban heat-island effect, and loss of green spaces. In response, cities such as Copenhagen, London, Singapore, and Chicago have announced mandates or incentives for vegetated roofs to reduce storm-water volume, clean air pollutants, reduce the urban heat-island effect, and sequester carbon dioxide. There also have been a number of demonstration projects for vegetated walls that offer similar benefits. However, the environmental benefits remain hard to monetize, and questions persist on whether urban vegetation will be a mainstream market or another green curiosity. Here, we examine the drivers as well as barriers for growth in this emerging market, and project the global market size for green roofs and walls from 2012 to 2017.