The Oregonian gives us this piece on a few of Portland's urban wall gardens, and makes a good point in the process: wall gardens are like green roofs that you can see and enjoy. Besides being beautiful, they help keep heat in in the winter, insulate walls to keep interiors cool in the summer, and provide "evaporative cooling" if you just happen to be strolling by. Nice.
Adding to the list of benefits are insulation from noise, absorbing heat and storm-water runoff, and of course, view improvement.
Check out the rest of the article here.
Images: Motoya Nakamura (top) and Mike Davis for The Oregonian