I sometimes dig holes in clay - you can actually arrange the clay around the
hole. Add leaf mold, compost etc. and then plant. Own root roses do very well
in this. Some of them are actually oasis (wild) roses from the Middle East.

Find a stump or log with a big hole in it. Place artistically. Fill the hole
and sides with good quality soil - leaf mold always works. Plant wildflowers
(especially on the shaded sides) and whatever you want. You can try sand in
this also.