Nah, just look at NY City's Centeral park. it looks natural, with rock out croppings streams, ponds, forests, meadows and field.. and all of it is carefully landscaped!

the "ponds" are semi natural, ie, there were wetland/marshy areas in the park boundries.. but now, the ponds have paved edges, with little docks (you can rent a row boat and paddle about) and the stream? all man made.. but as you walk along its meandering path, you'd swear it was all natural... a synthetic natural environment.

and the "bio sphere" or green houses or lots of other places could be catogorized the same way....