[1][2] The landscape garden within the park comprises 8 hectares (20 acres) and contains medieval ruins, several oaks, cypresses and poplars, grassy meadows, a wide range of exotic plants from various parts of the world, numerous watercourses and a large variety of rambling roses growing over the stone walls of the ruins.
The garden includes the ruins of the ancient settlement of Ninfa, whose name seems to derive from a classical era nymphaeum, a temple dedicated to nymphs, located on an island in the small lake; nymphs were believed to dwell in mountains and groves, by springs and rivers, and also in trees and in valleys and cool grottoes.
In 1171 the Holy Roman Emperor Frederick Barbarossa sacked and burned it, after the Pope, his enemy, had taken refuge in the town.
[6] During the Middle Ages Ninfa had more than 150 houses, several churches, mills, bridges, two hospices, a castle and a town hall.
The original structure most likely had a single nave with several lateral chapels and a semicircular apse, of which parts remain.
In 1765 the town hall was transformed into a barn by Francesco, Duke of Sermoneta, and, at the same time, Pope Pius VI started a reclamation of the marshes, but the project was abandoned.
The administration of the garden was left to a nonprofit foundation by Lelia Caetani and her husband, Hubert Howard, the last owners.
The plants thrived due to the favourable climate: the microclimate is very humid because of frequent rains and the river Ninfa.
Quest-Ritson's description of the site:The garden at Ninfa has a unique setting: the ruins of a medieval town near Rome.
[15] There are over a thousand varieties of plants and trees, such as American walnuts, several ornamental apples, yuccas, Cotinus coggygria, catalpa, cedar trees and many rose bushes, including multicoloured Rosa x odorata 'Mutabilis', the early yellow Rosa hugonis, and the pale pink 'Complicata'.
[16] Near the bridges are maples, poplars, Photinia serrulata, Gunnera manicata, papyrus, Casuarina tenuissima, jasmine, climbing hydrangea, purple flowered Clematis armandii, wisteria, Liriodendron tulipifera, cedars, wattle and a clump of bamboo from China.