Hensol Castle mansion, a house with seventeenth-centry origins but remodelled and extended from c.1735 onwards (nprn 18963) is situated within an eighteenth-century landscape park (700161) in rolling countryside on the west side of the Ely valley, to the south of Pontyclun. The mansion is now used as a hospital (since 1927) and hospital buildings have been erected on parts of the estate.
The pleasure grounds fall into two main areas: first, the gardens immediately around the house, and second the wooded grounds around the north end of the lake west of the house.

The gardens comprise informally laid out areas east and west of the house; and the formal garden south of the house. The informal areas probably followed the 1838 phase of alterations and were in place by 1877 when there was no garden on the south. The gardens are informally planted with mixed deciduous and coniferous trees and shrubs, with winding paths through them, bounded by the lake on the west, with level or gently sloping lawns and groups mixed trees and ornamental shrubs. Around the house are clipped golden privet and laurel bushes, and hydrangeas. To the east a sloping lawn above the drive is sparsely planted with a few specimen trees. West of the house are many fine mixed specimen trees
The formal garden south of the house (post-1927) is a large level lawn with a central north-south path, ornamented with clipped box, on the axis of the front door of the house, its north end covered by a modern rose pergola. At its south end steps descend to a drive to the hospital complex. On the south the lawn is bounded by a shrub border.

Around the north end of the lake is strip of wooded grounds accessed via a path across the top of the lake dam. It is an area of mainly beech and oak woodland underplanted with ornamental shrubs, with a path, the 'Tulip Walk', running through the wood, looping around its western margin. The wood is bounded on the north by a ha-ha suggesting an eighteenth-century origin. To the east of this area, adjoining the kitchen garden, was an orchard in 1877 but later became a conifer plantation.

Just north of the house is a walled kitchen garden (700162).

Sources:
Cadw 2000: Register of Parks and Gardens of Special Historic Interest in Wales, Glamorgan, 246-9 (ref: PGW(Gm)41(GLA)).
Ordnance Survey First Edition 25-inch map, sheet: Glamorgan XLII.5 & 9 (1877).

RCAHMW, 16 May 2022