History in Structure

This site is entirely user-supported. See how you can help.

Grotto, Underground Garden and Bridge about 60m to west of Dewstow House

A Grade II* Listed Building in Caerwent, Monmouthshire

We don't have any photos of this building yet. Why don't you be the first to send us one?

Upload Photo »

Approximate Location Map
Large Map »


Latitude: 51.5961 / 51°35'46"N

Longitude: -2.7704 / 2°46'13"W

OS Eastings: 346729

OS Northings: 188868

OS Grid: ST467888

Mapcode National: GBR JH.BMTP

Mapcode Global: VH7BH.X4RR

Entry Name: Grotto, Underground Garden and Bridge about 60m to west of Dewstow House

Listing Date: 29 March 2000

Last Amended: 29 March 2000

Grade: II*

Source: Cadw

Source ID: 23061

Building Class: Domestic

Location: In Dewstow about 1km north of the centre of Caldicot and situated on the north east side of Dewstow Road.

County: Monmouthshire

Town: Newport

Community: Caerwent (Caer-went)

Community: Caerwent

Locality: Dewstow

Traditional County: Monmouthshire

Find accommodation in


The Dewstow estate was bought in about 1890 by the agriculturalist Henry Oakley (died 1940) who was mainly responsible for laying out the very elaborate gardens in the years round about 1900. He may well have been influenced in their design by E J Lowe (died 1900) who lived at the nearby Shirenewton Hall and was also a fern grower. The underground gardens, constructed mainly of concrete block, brick and artificial stone (perhaps Pulhamite), are large and remarkable. The three surviving areas are listed separately.


The main drive is carried by a balustraded segmental arched bridge which crosses a winding stream which emerges from a stonework Gothic arch. This arch leads to a small 'gorge' with tiered rockwork on either side and the stream running in small winding channels in the level artificial rockwork floor, creating stepping stones through the arch. In the east side is a small semi-circular pool. An arched entrance leads to a winding rockwork passage into an underground garden.


Just inside the entrance of the garden, on the right hand side, is a caved-in passage into the underground garden to the east. Most of the floor is taken up with a naturalistic pool, with stone steps across it. There are pillars of rockwork with niches for ferns, and at the north end is a waterfall which is said still to work. The chamber is top lit but the glazing has gone, leaving only the iron and re-inforced concrete framework. The water for the gardens was carefully controlled and there are various standpipes and water cocks hidden in the niches. This garden was intended for growing ferns, a speciality of Henry Oakley's.

Reasons for Listing

Included as the garden features of an early C19 villa with well preserved character which was occupied for a long time (c1890-c1940) by Henry Oakley, a well known horticulturalist and breeder of shire horses. The garden is principally his work and includes these exceptionally fine and well preserved grottoes from about 1900 which were designed for the growth and display of ferns, an Oakley specialism. It is highly graded for these reasons.

Other nearby listed buildings

BritishListedBuildings.co.uk is an independent online resource and is not associated with any government department. All government data published here is used under licence. Please do not contact BritishListedBuildings.co.uk for any queries related to any individual listed building, planning permission related to listed buildings or the listing process itself.

British Listed Buildings is a Good Stuff website.