i would be curious what the engineer on that job thinks. i wonder if it was omitted from the construction drawings or the contractor omitted it. even if it is just a 3 foot area, that 3 foot is the most crucial when directly adjacent to a structure. where is all the water going from that impervious roof??? if there are gutters on the home i would suspect a large portion is being directed to that "little 3 foot flower bed" how many years has this wall been in place?