I think that is one of the big keys to
permaculture that has been sorely neglected.
When planning a guild, it seems that you generally want some tap rooted plants mixed in with high rooted plants and mid level rooted plants. But which are which?
And when planting in rocky crevices - only a few plants are good with that.
And while some plants will do okay with shallow soil, they will do much better with deeper soil. And for others, they will do just as well with shallow or deep soil.
I'm gonna get it ....