Another approach: Your plant choices expand if you design a boardwalk low to the ground. In this case, you can pretty much work with plants of any height. Just don't impede foot traffic with aggressive, horizontal growers.
Love the mounding with stones in between.
garden in Japanese hotel courtyard
What's the Difference Between Geology, Geoscience and Earth Science?
Earth Art Gallery: Penjing is the ancient Chinese art of creating landscapes, including plants, water and miniature figures and structures, on stones. It's considered the ancestor of suiseki.
No Grass Landscaping Ideas | Landscaping Back Yards Design Ideas, Pictures, Remodel, and Decor