Vertical vegetation is vegetation growing on, or adjacent to, the unused sunlit exterior surfaces of buildings in cities. You may or may not know that there are three different kinds of living walls.
The most basic kind is the kind that a climber simply covers the wall or a trellis near the wall.
The second kind was invented by Patrick Blanc and is comprised of layers of synthetic felt through which plant roots are hung (the foliage sticks "out" if that makes sense).
The third kind is a series of pockets or planters filled with soil and supported by the wall.
I'd like to introduce a 4th kind.
I'll start by talking about layering. Wikipedia tells us that: "Layering is a means of plant propagation in which a portion of an aerial stem grows roots while still attached to the parent plant and then detaches as an independent plant."
What I am proposing involves the same method but never severing away the rooted branch. This creates a tree that has it's root system distributed. And so, if this idea is repeated over and over we can grow trees that have no roots in the ground. Instead they have an elevated distributed root system in many containers.