The Penllergaer estate is located to the north-west of Swansea, on the immediate south side of the M4 motorway. It is notable for the partial survival of a very important picturesque and romantic landscape of the mid nineteenth century. It was the creation of John Dillwyn Llewelyn (1810-1882), a polymath and a nationally important figure in horticulture, who transformed the river valley with the creation of lakes and waterfalls, combined with profuse and exotic planting, to produce a romantic and almost alien landscape. He was able to realise the dramatic and functional potential of what was already a very pleasing place in a relatively small compass, merging innovation, domesticity and wilderness.

The site is unusual in that there are numerous contemporary photographs of it, taken by Llewelyn who was also a pioneer of photography. Much of his exotic planting has gone but despite severe encroachment by post-war development the core of this landscape remains essentially intact. The structure of his landscaping survives, as do the ruins of his pioneering orchideous house (nprn 19644) in the kitchen garden.

The park was largely created from 1833 onwards. It is aligned roughly north by south along either side of the craggy valley of the Afon Llan which follows a winding course down valley to the south. It extends from Melin Llan in the north to Cadle Mill in the south, a distance of about 3km. The far north end has been truncated by the M4. Penllergaer House, rebuilt by John Dillwyn Llewelyn in 1835-36 but demolished and replaced by council offices, which in turn were replaced by housing (19645), occupied an elevated position at the northern end of the park, on the west side of the river. The location is dramatic with the ground below the house falling away steeply into the valley and to the upper lake. The main entrance was from the south, at Cadle Mill (24926), with a (restored) lodge of 1834, the Lower Lodge, at the entrance. The drive, now a track, follows a circuitous route north along the west side of the valley through scrub and light woodland. Below, in the valley floor, a large swampy area was formerly an informal lake with islands and which once occupied a large part of the southern end of the valley floor. Part way along are two ruinous lodges, Middle Lodge and Upper Lodge. Further on the drive passes a quarry, embellished as a picturesque landscape feature that was gardened and had a waterfall in the north-west corner with a log cabin, now gone, at the top of the waterfall, reached by paths from the walled garden (700390).
Beyond here the drive swings westwards to the site of the forecourt on the south front of the house, then north towards the modern A48. This and other drives west from the house have been largely destroyed but North Lodge and the adjacent School House survive as private residences.

The lake below the house site is dammed at its southern end with substantial rockwork of flat stones, made to look like a natural outcrop or cliff, over which three waterfalls cascade and with a viewing platform located on the west bank. Paths run down and across the valley, one leading to the west side of the former, lower, lake. Both lakes had boathouses, now gone, only footings remain. Llewelyn conducted experiments here with ‘a small electric galvanic apparatus’ to propel boats and was demonstrated to the British Association for the Advancement of Science on a visit in August 1848.

Much tree and shrub planting took place from 1833 onwards. The 1876 Ordnance Survey map shows the completed landscape, indicating clearly that it was almost completely wooded - the only open area was the field between the Middle and Upper lodges, which ran in a narrow tongue down to the north end of the lower lake. The same map portrays gardens created by Llewelyn around the house when it was rebuilt in the mid-1830s, but these areas have been lost to development. His equatorial observatory survives to the west of the house site in the green space at the centre of a new housing development (23083).

Sources:
Cadw. 2013. Register of Parks and Gardens of Special Historic Interest in Wales: (ref: PGW(Gm)54(SWA)).
Ordnance Survey first-edition six-inch map, sheet: XIV (1884).

RCAHMW, 25 July 2022