We quantified the amount and diversity of vegetation on ten green facades and compared it to nine naturally colonized wooden barns located in the humid temperate climate of eastern North America. The leaf area index (3.3 m 2 -vegetation/m2 -wall) and canopy thickness (61 cm) of the green facades was nearly identical to that of the barns (3.1 and 69 cm), indicating that green facades mimic nature’s architecture. Predicting the biomass of façades from models developed for the barns’ canopies, indicated they should range from 1000 to 1400 g/m2 (5600 to 8000 g/m2 , fresh weight) but could be as much as 2900 g/m2 (21,000 g/m2 fw). The façades included a total of 14 vine species while the barns included 8. There was an average and maximum of 3.2 and 6 species on the facades and 2.3 and 4 on the barns. The biodiversity of the cultivated system closely mirrors the colonized system, suggesting that an optimum biodiversity may exist for vertical, vine based living architectures.