I think a simple hedge or so would do the trick. I mean, it's part of the garden, and it is also a barrier that would set the boundaries of your garden. I think it's a win-win situation for everyone, and it STILL is a part of the garden, plants and all, so it wouldn't look so out of place, compared to other suggestions like rock formations, or just wood panels. I don't know, it seems pretty low maintenance and it has that majestic theme to it, and that's why I really like the idea. Also, maze, who doesn't like to have a maze in their own backyard?