Buildings often come off as ugly concrete, sometimes shiny pretty glass. Either way, buildings tend to be inorganic. The GrowSpot has some beautiful photos of work done by Patrick Blanc. Blanc incorporates plants in the exterior of buildings by attaching a fibrous material to the building. The plants then take root in that and water is trickled down behind it. I love the idea to get more plant life back in the cities where its been lost. Imagine 10 or 20 stories buildings covered like this. I imagine there is also some insulating attribute to this as well.
This is also slightly different from your typical gardening. A Google search for vertical gardening has great tips for pole beans and sugar pod peas but nothing on sticking plants to buildings. Wikipedia has nothing on it yet either. This form of gardening varies because it seems to mostly be aesthetic but promises to be functional for insulating purposes. I don’t think it would be too practical to actually grow food on large buildings this way. Someone should try it on their house though.