How about creeping thyme? Heard they're pretty low maintenance, no mowing, not much watering or care and can tolerate being walked on. They have lovely flowers too, smothering the whole of ground area. I don't know this for sure but they might give off nice fragrance when walked on. I had thought of having this for a shaded and narrow walkway not wide enough for lawnmower. The other option I had thought of was moss.

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