Rhiwlas Hall, a twentieth-century house on a more ancient site (nprn 28709), is located within a small but well-preserved landscape park on the east bank of the Afon Tryweryn (700264). The house is surrounded by gardens which date largely from the nineteenth century. In uneven terrain its walled gardens occupy a flatter area to the east of the house, on the north side of an informal garden area (265327).

The garden comprise two conjoined areas, aligned east by west, enclosed all round in brick and stone. They are likely to be contemporary with the early nineteenth-century (predecessor) house though the hand-made brick used suggests a possible earlier date. The smaller, western one is now disused and inaccessible. It is an irregular quadrangle, its walls lower than the east garden walls (2m), with entrances from the neighbouring garden area and from outside. It contained a glasshouse and still has some fruit trees growing.
The main, eastern, garden is larger and rectangular, its long axis east by west, walls 2m-3m high and showing much evidence of collapse and repair. Still in use, there are original entrances in all walls aside from the east. The interior was, and still is, laid out by perimeter and cross paths dividing it into quadrants, the two northern areas smaller because of several large glasshouses along the north wall of which only bases remain. They included a pear house, a vine house, and a sunken melon pit. The eastern half is now rough grass with a few old fruit trees. The south-west quadrant is also rough grass with a few fruit trees and a small duckpond.
At the central crossing of the paths is a raised circular bed with an ivy-covered retaining wall and ornamental planting. Three parallel paths lead off to the north creating two wide borders between them, an arrangement shown on the 1901 map.
A range of buildings outside the north wall included a boiler house which has now gone, but there remains a fine post-War concrete-framed greenhouse.

Sources:
Cadw 1998: Register of Parks and Gardens of Special Historic Interest in Wales: Conwy, Gwynedd & the Isle of Anglesey, 292-5 (ref: PGW(Gd)25(CON)).
Ordnance Survey second-edition 25-inch map: sheet Merionethshire XIV.15 (1901).
Additional notes C.S.Briggs.

RCAHMW, 18 June 2022