A walled garden is a garden enclosed by high walls, especially when this is done for horticultural rather than security purposes, although originally all gardens may have been enclosed for protection from animal or human intruders. In temperate climates, especially colder areas, such as Scotland, the essential function of the walling of a garden is to shelter the garden from wind and frost, though it may also serve a decorative purpose. Kitchen gardens were very often walled, which segregated them socially, allowing the gardeners, who were usually expected to vanish from the "pleasure gardens" when the occupants of the house were likely to be about, to continue their work. The walls, which were sometimes heated, also carried fruit trees trained as espaliers.

A garden is a planned space, usually outdoors, set aside for the cultivation, display, and enjoyment of plants and other forms of nature. The single feature identifying even the wildest wild garden is control. The garden can incorporate both natural and artificial materials.