"I like the easiest kind of plants, a garden that grows by itself," she said. "That's the kind I like."
That may seem a simple philosophy, but it was "revolutionary" in 1959 when she began to create her home's surroundings, garden manager Marsha Bode said.
Back then, neat and tidy tract homes were multiplying in post-war neighborhoods, with neat and tidy yards around them.
Miller and her husband Oscar moved to Laguna Beach from the Midwest, because, according to Hortense's own account, she fell in love with bougainvillea while on a trip to Mexico.
Oscar died of a lengthy illness only months after the house was completed, leaving Hortense to live on for many years.
"He wanted her to have the house," Bode said.
Hortense had her own ideas about gardening and, at 50, was ready to put them into practice in her new California home.
Born in St. Louis, Hortense had studied at the Art Institute of Chicago, developing a meticulous folk-art style that is found throughout the house and gardens.
Her artwork decorates the house and the patio walls, and some furnishings. Murals and wood carvings of mermaids ? her favorite motif ? astrological signs, and symbols of air, earth, fire and wind are found throughout the property. Colors are earthy rather than bright.
"She was mostly self-taught," Bode said of Hortense's art. "The house is frozen in time. It has not changed since she moved in."
The house's modernistic style is evident with its open courtyards, huge windows and lean lines. Meandering pathways with stone and railroad-tie steps crisscross the slopes below and above, leading to solitary benches with wonderful ocean views.
The garden home ? and the gardener herself ? has a magical quality, a presence that is not lost on visitors, who have numbered in the thousands since Miller opened the gardens for public touring in the mid-1970s.