Foliar tapestries are impressive in the right situation. https://tonytomeo.wordpress.com/2018/02/25/foliar-tapestries/ They work as nicely on exterior walls as conventional tapestries or paintings might work on interior walls. However, they require much more maintenance!
Trendy green walls are overrated. Their only real advantage is that they are pretty. They are not a ‘real’ solution to anything. They may keep the interior of a small building a bit cooler, but no more than light colored paint or a shade structure would. They do not save water, and actually use more water than plants grown in the ground. All that water is likely to rot the walls behind, or the decking below. They do nothing for melting glaciers or saving the planet. In a few more years, when they are no longer trendy, they will be more junk in the landfills.
Most obtrusive exterior walls can be obscured or partly obscured with less demanding plants that grow either up from below, or downward from above. Unpainted concrete walls can be outfitted with clinging vines if space is inadequate for upright shrubbery or a shorn hedge in front. Backfilled retaining walls can be outfitted with pendulous or ground cover plants that can cascade downward for a few feet.
A non-horticultural option is a good old fashioned mural. Yes, the sort that get painted on. They are about as expensive as foliar murals are, but once installed, they can last for years with only minimal maintenance, and no watering.
There is much more detail to the murals shown here. These are just close up pictures of little dogs who were memorialized in the murals. Incidentally, the only sweetgum tree in Felton Covered Bridge Park is a memorial tree that was planted for Charlie, the Boston terrier in the mural below.