During the 1890s, as part of a belief in “moral treatment” of psychiatric patients, patients were thought to derive to benefit from being outdoors and involved in farming activities. From 1835 to 1905, the State Hospital for the Insane (now the Augusta Mental Health Institute) purchased and consolidated several neighboring farms. For more than a century, the hospital farm provided crops and livestock as well as occupational therapy and exercise for hospital patients.
Formerly known as the Pine Tree State Arboretum, the botanical garden boasts of 224 acres of plants belonging to more than 300 different species of plants and trees. There are nature trails at the site, which can be used for pleasure strolls and biking and which lead to woodlands, forests, and ponds, as well as farmland which once served as a State Hospital farm.
A visitor can still see the valve station used for controlling water flow from the earthern cistern (now the Pavillion) to the hospital. The granite quarry just beyond the Rock Garden is one of the areas where granite was cut from a quarry deposit and used for various projects including
foundations of the hospital. There are also the remains of the animal stalls along the trail to the bridge at Viles Pond.
The Maine Forest Service began development of the Arboretum in 1981. During that year, 120 trees were planted and construction of fences, bridges, trails, and a boardwalk began. A board of directors to manage the 224-acre preserve, then called the Pine Tree State Arboretum, was formed in 1981, and in 1992, a 99- year lease was signed with the Department of Conservation, administered by the Bureau of Parks and Lands. The Arboretum was renamed the Viles Arboretum in 1992 to honor William Payson Viles and
his wife, who were instrumental in establishing the Arboretum. An education wing was built in 2003. The Arboretum is continuously adding to its collection of trees and plants, its educational activities, programs, events and its trail system.