Oooo, I know this one. This is a first, by the way.
I have wanted to do this for years, but live on property with no room for it: a "talus." It's a lovely little Earthen structure, almost a fence made of a hill, with trees on top of it. It can be made with the sides quite steep since the roots will hold it together. Apparently, they are, or were, very popular in rural France; I first read about them on the site frenchgardening.com. I do like the hedge idea very much, if it is done in the old way of pleaching the plants together. Hopefully, you have already found a satisfactory answer. I had to add my two cents, thank you.
