Vertical Garden of Soria

I had a chance to see this garden vertically, the idea is good but something has gone wrong. There isn´t a single healthy plant. I think that in this type of garden there is very little soil and its not watered much. If I see it again someday I hope to see it better kept. I'll stick with this interesting tree I found in the natural park of river wolves. It seems to be a squirrel climbing up the tree, but it isn´t...