This study aimed to examine the plant diversity and plant performance of vertical greening system (VGS) and how the hardware setup (including growing substrates) potentially affect plant performance. A total of 125 VGS (including 85 outdoor and 40 indoor VGS) were surveyed in Hong Kong. We recorded the type of VGS, species composition, frequency and plant coverage; substrate medium type, and plant performance. The findings revealed that indoor soilless VGS performed comparably well as on conventional soil, and outdoor soilless VGS performed significantly better than on soil. Regardless of substrate type, plants on indoor VGS performed better than outdoor VGS.