The most important thing is not to expose them to the weather and, obviously not to let them get wet: water is indeed the only real enemy of vertical gardens, as it is able to interrupt preservation and thus cause the deterioration process to reactivate.
Obviously, other factors that may affect how long a green wall will last and how beautiful it will stay over time include direct sunlight exposure, excessive touching (plants that have been damaged through human touch will not be able to regrow and renew themselves), as well as particularly high humidity rates. Therefore, the only thing you can really do for a vertical garden is… forget about it! Or, we should say, only remember about it when you wish to admire its beauty, as it does not need any maintenance whatsoever, and, in fact, the least you touch it, the more it will last.
Cleaning is also easy and quick: preserved vertical gardens have no electrostatic charge and therefore do not collect dust (just like they do not attract insects). In order to remove any dust particles that are naturally present in the air, simply blow with a light air jet occasionally.