So here's the plan.
My rock garden (rockery) will be a rocky outcrop among the trees.
My border will be a sunny hillside clearing in the woods.
My fern garden will be a shady grove, with narrow winding paths and Spring wildflowers among the trees.
My bog and pond gardens will be the Marsh edge.
The rest of my 'garden' will be native plants spread along trails through mixed woods.
I used to worry about how to manage the change from a worked garden to a natural area, but now I will think about every planting area as being part of the surrounding woods. I will make my garden fit into the existing natural landscape.
Interestingly, it'll be a garden with no edges.