The Dderw is located a short distance to the north-west of Rhayader. It is a nineteenth-century house on a more ancient site (nprn 81174). It is notable for its well-preserved wooded grounds, around the house, with its fine Arts and Crafts terraced garden established by the 1920s. House and grounds form part of a small parkland estate, an area open parkland located south of the house (700150). Once the centre of a vast estate the property remains in the hereditary ownership of the Prickard family.

The gardens lie to the south and east of the house. They cover about three acres (1.2 ha) and are enclosed on the north, west and east by ornamental mixed woodland belts which extend to the park boundary. The house is approached from the west to a forecourt partly bounded by yew hedges with topiary. On the south side of the house are two wide open grass terraces accessed by steps from a hardcore terrace alongside the house. Their east and west sides are flanked by shrubberies blending into woodland beyond. The upper grass terrace is revetted, the lower one, which extends east along the full legth of the garden, terminates at a ha-ha with a sundial on its south-east corner.

On the east side of the house is a rectangular Arts and Crafts Italianate terraced garden descending the south-facing hillslope in five tiers. The uppermost is a lawn surrounded by narrow borders and  enclosed variously by high stone walls, a yew hedge, and a raised walk on the north. Late nineteenth-century maps show the residence and garden with glasshouses forming an integrated range to the north of the lawned area with a sundial. 

An ornamental iron gate on the south connects the remaining four levels on a central axis, linking them by flights of steps, in addition to steps down the west side. The second level is a wide stone-flagged terrace enclosed on the south by a low wall, a narrow border along its north side. From this level the garden is enclosed on the west by a high clipped yew hedge. The third and fourth levels are similar, both with narrow strips of grass set between narrow borders on each side of the central path. The fifth, lowest, level is a lawn set with small box-edged beds around a central sundial on a stone column, enclosed on the south by a high yew hedge with an iron footgate as well as a gate on the west. Like the forecourt, the angles of the garden hedges are marked with clipped topiary balls. The plantings within the terraced garden is typically 'English' including lavender, old roses, fuchsias and heathers. This garden area may replace a more formal predecessor, the new design possibly dated by an inscribed stone of 1810 ('J.Jones 1810 H.T.') on the eastern garden wall.

No significant changes to the gardens are believed to have taken place since the 1920s.

North-east of the house, conjoining the garden area, is the kitchen garden (700151).

Sources:
Cadw 1999: Register of Parks and Gardens of Special Historic Interest in Wales, Powys, 52-5 (ref: PGW (Po)2(POW)).
Ordnance Survey first-edition 25-inch map, sheet: Radnorshire XV.9 (1888).
Additional notes: C.S.Briggs

RCAHMW, 11 May 2022