Picture this cylinder hanging vertically from a position on Level 4, down past L3 and L2 to finish above head height on L1.
Now think of it it covered with assorted plants from top to bottom, growing from a point level with L2. (Checked with a plant advisor and it is very feasible and there is a good choice of plants.).
For structural and safety reasons the wire tube will be fastened at L4 to the steel structure by an engineer approved method. The tube itself will also be approved.
Advice from a plant consultant is that L2 should be the location of an embedded or attached container that will be the origin of the plants. Maintenance in general will also be from this point.