IMO the question what the 5% area requirement refers has been clarified (see post headed"Full credits achieveable for less than 1% landscape?" futher down below).
What stays is the definition "on the ground". Assuming a project where the plot has a basement on 100% of the plot size. But there are no portable planters / pots or similar, but the project installs a planting bed with a depth of approx. 1.5 meters. IMO this would be vegetation on the ground and not a planter.
Any thoughts on this?