I've seen beautiful plantations of herbaceous perennials plants under mature deciduous trees and I would like to plant something similar.
My concern is for the tree itself (an Autumn Blaze maple in this case).
I have often read on this site that trees respond badly to changing the height or grade of the soil above their roots. So this precludes simply adding 6 inches of soil inside the drip line section.
I once tried digging around but the three (planted 2 years ago at that site, bought at a nursery it was about 8' to 9' tall) already has many small roots in all directions which I assume are from this tree and I fear that by digging holes I will be damaging it.
What is the best way to proceed or is this just a bad idea?