Beatrix Farrand was one of the great landscape designers.  If you can get to only one of her gardens, make it Dumbarton Oaks in Washington, DC.  This is where I first became aware of her work. The moment I passed through the orangery into the Green Garden, one of many garden rooms and spaces, I could feel her brilliance.  She provides reassuring formal spaces, open naturalistic areas, and even works in a lovely orchard.  Each space flows seamlessly into the next.  And no detail is too small.