I’m no expert and I don’t know the specifics of this vertical garden but trees and shrubs of that size usually have deep and wide root systems that give them incredible resilience. Without that root system and huge volumes of dirt to support it, the plants probably require a ton more monitoring by actual botanists instead of just landscapers.
I don’t think the problem is just the amount or cost of maintenance but how slow it is: the maintenance staff work on the outside of the building hanging from the top. Safety procedures alone would eat a lot into that work time.
I don’t think the problem is just the amount or cost of maintenance but how slow it is: the maintenance staff work on the outside of the building hanging from the top. Safety procedures alone would eat a lot into that work time.