All three gardens use natural settings so artfully that it’s sometimes hard to tell where the landscaping ends and nature begins.

Farrand, the sole woman among the founders of the American Society of Landscape Architects, was born in New York in 1872 and died in Bar Harbor in 1959. She designed gardens for the White House, consulted at Princeton and other institutions, and had many prominent private clients, including John D. Rockefeller Jr. and his wife Abby.

Farrand worked with Abby Rockefeller to design the private garden in Seal Harbor between 1926 and 1930. The property is still owned by the Rockefeller family. Each summer, the garden opens to the public one day a week, but reservations fill up fast. As of mid-July, only a handful of slots were left for late August and early September. And there’s no sneaking in: To be admitted, your name must be on a checklist at the entrance, which is virtually unmarked and hard to find even with directions. Photos are permitted only for personal use.

Once inside, most visitors head to the rectangular lawn, where the borders burst with colorful flowers and plants familiar to any backyard gardener, from bright purple clematis vines to gray-green dusty miller. But in some ways the Rockefeller garden is at its most stunning away from the sunny flower beds, where the landscaping melts into the woods. Forested paths are carpeted by velvety moss; giant hostas and feathery ferns offer contrasting textures and a palette of greens. A stone wall punctuated by doorways shaped like the full moon or a bottle give the feeling of stepping into a secret garden hidden in a magical forest. The property also displays centuries-old Asian art, ranging from Buddhas to tall stone figures lining the walkways.

David Bennett, a landscape architect in Washington D.C., has visited the Rockefeller garden as part of his research for restoration of Farrand’s kitchen garden at The Mount, the country estate in Lenox, Mass., created by Farrand’s aunt, writer Edith Wharton. Bennett says Farrand wanted her gardens to “fit into their natural settings. She had a strong appreciation for the natural character of the land and the appropriate way of integrating a designed landscape with its natural context.”

She used plants to create “impressionistic” effects of texture and color, and was also known for creating outdoor “garden rooms,” with “the idea of moving through a landscape in a sequence, from one space to another, where each space has its own character,” Bennett said. “One space may be very shady and enclosed, and you pass through a hedge or a row of trees or through an actual gate in a wall to enter a very sunny and open space.”