The Romans had gardens in various forms, both in the cities and in the countryside. They are known to us primarily from Pompeii and Herculaneum near Naples, the cities destroyed in ad 79 by the eruption of Mount Vesuvius, where the volcanic material covered and preserved extensive finds. In Rome itself they are attested for the middle of the fifth century bc, inasmuch as the Law of the Twelve Tables made provision for the boundaries of neighbouring properties (Tab. 7.2): an olive or fig tree might be planted no nearer than 9 feet from the property line, and other trees no nearer than 5 feet (cf. Tab. 7.9a/b and 10; Plin. nat. 16.15). The garden formed a central economic base so that, at that time, a farmstead near Rome was not yet called a villa, but rather a hortus (garden) (Plin. nat. 19.50).

The kitchen and vegetable garden was the oldest form of Roman garden. It is attested since the fourth and third centuries bc, and was widespread in Pompeii up to the second century bc. In private homes one passed through the tablinum (picture room) of the atrium into a small vegetable garden (hortus). The garden was thus in the back part of the lot, and grew not only vegetables, but also fruit trees and some vines, as in the House of the Surgeon or the House of Sallust. Even smaller houses had at least a corner for herbs and flowers, which shows the general desire for green space. The peristyle garden had its origins in the peristyles (arcades) of Greek houses, which the Romans adopted in the late second century bc, and greened by means of artificial irrigation (House of Sallust, House of the Vettii, House of Polybius). These gardens were now no longer only kitchen gardens, but also decorative and pleasure gardens, for which the plural word horti was common, even if the Romans did not make the distinction until the height of the imperial era. If one or several porticos (columned halls or arcades) enclosed the garden, it was called a xystus, which often extended as a terrace in front of the longitudinal facade of a country house. The walled garden was called a viridarium (pleasure garden or park).