We made an unintentional hugelkultur bed out of our old pond--before learning about hugulkultur. It's about three feet deep, eight feet diameter, and filled with a lot of branches, trimmings, etc, and is in the process of being covered in topsoil from another part of the garden. It's situated right underneath a mature horse chestnut and gets pretty much no sun in the summer, and minimal sun in the winter. I was thinking of growing something edible for our free-ranging 7 chickens, but will anything actually grow there? It's at the southern edge of our very small garden, and is also in the rain shadow of the tree (obviously).
I know that the onion family, the currant family, the blackberry family and strawberry will grow under the shade. you could try the seaberry it normally get a 30lbs per shurb yeild in reg sun, and you could also try out the autumn olive family. Then there is the artic kiwi (not regular or hardy, but artic) and bird ear bug so any flowering plant that will attract bugs for them to eat.
Iterations are fine, we don't have to be perfect
Rocket Mass Heater Plans: Annex 6" L-shaped Bench by Ernie and Erica