Fonmon Castle, a building with twelfth-century origins (nprn 300300), is located to the west of Barry. It situated in grounds on the western lip of a steep ravine below the gardens and castle in which the Fonmon Brook runs northwards to join the Kenson river (700191). Fonmon is notable for its walled, terraced and informal gardens form an attractive setting for this ancient castle, continually occupied since the mediaeval period.

The gardens originated in the second half of the seventeenth century with modifications made over the following centuries. They occupy a roughly rectangular area, elongated north-south, to the south and west of the castle. Most of the area is level, but on the east the ground drops steeply down to the ravine of the Fonmon Brook and the gardens extend part of the way down the slope. The gardens fall into two main areas: the lawn, walled garden and kitchen garden to the west of the castle, and the informal garden to the south, truncated at the south end by the B4265 cutting.

North of the drive is a level lawn flanked by a row of five yew trees, remnants of a former hedge. Near the house the ground rises in two steps to the level of the main part of the lawn and a flight of steps leads up to it, with further steps up to a raised platform in front of the Venetian window of the house. Along the east side of the lawn a stone wall forms the upper part of a substantial revetment wall bounding the garden.  The lawn is bounded on the north by a hedge which divides it from the kitchen garden (700192). On the other side of the hedge is a circular stone-edged pool, box hedge around it, and nearby rose and shrub borders. The west side of the lawn is bounded by a 3m high wall beyond which is a small walled garden.

The garden south of the house and drive is mostly lawn, large and level, part planted especially to the south, and with flagstone paths near the house and flower borders along the east side and against the stable block. Plantings include sweet chestnuts, cedar and plane. The lawn here is bounded on the east by a crenellated stone revetment wall with a parapet about 1m high, reducing to a lower revetment wall to the south. Below is a steep drop into the wooded valley and views out across it from the terrace. Near the castle a flight of steps, flanked by low walls, lead southwards down the slope to a sloping path against the revetment wall and, eventually, down into the wooded valley. Features in the garden include a disused quarry ornamented with a pond and a small informal rockwork cascade fed from a tank in the stables; and in the south-east corner stands a tall, narrow, battlemented tower or keep, called the Watch Tower (37541).

The garden incorporates the line of the old drive, still visible, and part of the ha-ha.  

Sources:
Cadw 2000: Register of Parks and Gardens of Special Historic Interest in Wales, Glamorgan, 240-44 (ref: PGW(Gm)39(GLA)).
Ordnance Survey first-edition 25-inch map, sheet: Glamorgan L.1 (1877).

RCAHMW, 23 May 2022