The landscape at Sunnylands Center & Gardens was designed by The Office of James Burnett, with horticultural consultant Mary Irish. Inspired by the Annenberg collection of Impressionist and Post-Impressionist paintings, the gardens were designed to reflect the importance of these paintings to the Annenbergs, who bequeathed the collection to the Metropolitan Museum of Art in 1991.

Over 70 species of native and arid-adapted plants from North and South America, Africa, and the Mediterranean are displayed in the nine-acre gardens.

Although Leonore Annenberg did not live to see the Center's completion, it was influenced by her vision. The Los Angeles architectural firm of Frederick Fisher & Partners, which has restored three houses by the estate’s original architect, A. Quincy Jones, references the midcentury modern style of the historic house, with its signature roof, outdoor trellises, exposed wide-flanged columns, and circular driveway. Two 16-foot-high walls faced with lava stone from Utah are an homage to the 11-foot-high walls faced with lava stone from Mexico in the original house. The walls create a grand frame for the Center's interior space.