Use low walls and a floor to establish the room's footprint
An outdoor room can be located almost anywhere in your yard, but there are a few guidelines for creating one. They typically require some sort of floor, such as crushed stone, brick pavers, or even a patch of steppable ground cover. You'll also need walls: A simple hedgerow, picket fence, or adjoining trellises can create a boundary.
What was done here: The remains of the 5-foot stone foundation Bruce found on his property are tall enough to provide a sense of enclosure but not so high that you can't peek over them and take in the view. Working with Tim Cleary, he laid a bed of pea gravel to form a stone floor, then outfitted the space with a table and chairs and a bar cart for an outdoor dining and entertaining room.
More take-home tips: You could build your own sitting wall of mortared stacked stone. At just 17 or 18 inches high and 1 to 1½ feet deep, topped with flat capstones, it easily doubles as a bench.
For a planted border, consider evergreens such as boxwood, holly, or privet. All-season greenery will help define the space and prevent the spread of loose gravel into the grass—and vice versa. Choose dwarf varieties to keep pruning to a minimum.