The designed landscape at Locust Grove is a living collection in two parts. The Park, created by Samuel Morse during his residency (1842-1872) is a rare survivor of the 19th century romantic landscape movement which advocated a painterly, idealized approach to nature. Trees, native and exotic are sited in naturalistic groupings along an oval drive. The mansion is gradually revealed as the visitor approaches through majestic maple, beech and oak trees.
The half acre ornamental garden reflects the pre WWI style and taste of its owner, Martha Young, an avid plant collector. It is organized within a rectangle, 150 feet in length, edged with boxwood and planted in a succession of large blocks, each devoted to a single type of plant. The largest collection, peonies, have grown here for more than a century. They are flanked by collections of heirloom dahlias, annual and perennial flowers extending seasonal interest from early spring to late fall.
In addition, a large vegetable garden exhibits heirloom varieties and growing practices from the 18th, 19th, and early 20th centuries.