Shane's Castle Camellia House, Shane's Castle Park, Antrim, Co Antrim

Shane's Castle Camellia House is an early 19th century conservatory built in a delicately detailed castle style, designed by the prominent English architect John Nash as part of a group of additions to Shane's Castle. It was built for Lord O'Neill at approximately 1812 to 1816 and stands within a well-wooded demesne on a broad terrace overlooking Lough Neagh, enjoying an unspoiled setting of considerable architectural and historic interest.

The building is rectangular and single-storey, with an entrance at each end and a long arcaded glazed front. It is constructed in what appears to be Portland stone ashlar on its principal elevations.

The main front elevation faces south-east and consists of a crenellated ashlar stone façade containing thirteen moulded semi-circular arched openings. Each arch is carried on triple clustered columns rising from moulded bases to small scalloped caps. The bases stand on a deep sill projecting over a low plinth at ground level, and the arches are surmounted by a continuous arcaded drip moulding. The windows are of timber, each composed of two large rectangular lights with six rectangular pane divisions in each, and every division contains four panes that overlap the one below and are cut with a segmental shaped bottom edge. Above each window is a semi-circular fanlight, radially glazed with seven pane divisions, each division containing two panes of the same overlapping segmental type. The fanlights are bottom-hung and open inward. The windows are set in moulded timber frames rising from smooth rendered base blocks positioned behind the clustered columns, with smooth rendered panels between them. Above the arched drip moulding is a projecting moulded stringcourse, surmounted by a crenellated parapet. A number of the windows have broken glazing, and all have later timber-framed protective metal mesh panels affixed to them.

At the right-hand extremity of this elevation the walling is of exposed brickwork where an adjoining block remains incomplete, with a canted basalt and sandstone bay projecting from it and left unfinished. At the left-hand extremity is a slightly projecting rectangular end bay in finely jointed ashlar stone, with a projecting plinth and similar stringcourse and parapet; it contains a blind arrow loop slit.

The main entrance elevation faces south-west and is single-storey. The entrance comprises a central semi-circular arched doorway set in a rectangular panel of ashlar stone, which projects slightly from the centre of a bow with snecked basalt rubble sides curving back to join a taller flanking tower on each side. The flanking towers are of basalt rubble with stone quoining to the outer corners, and share the projecting moulded stringcourse and crenellations of the central element. Some ashlar parapet blocks have been repaired in brickwork and render. Each flanking tower contains a Gothic arched window at low level, with Gothic arched timber fixed lights having horizontal pane divisions, set in splayed reveals and sill with a moulded label. The doorway itself consists of a pair of rectangular timber glazed and panelled double doors, surmounted by a rectangular four-pane glazed panel and above that a semi-circular seven-pane radially glazed fanlight, all set in a moulded timber frame recessed behind a moulded semi-circular arch carried on twin clustered columns with scalloped caps matching those of the main elevation. The doorstep is of cement.

The rear elevation is of one storey over a basement storey, built in random rubble with some brickwork including brick dressings to small rectangular window openings. The parapet has sandstone crenellations. At basement level there are large rectangular recesses with timber lintels surmounted by flat brick arches. At the right-hand extremity is a projecting brick buttress at the junction with the side of the terminal turret of the main entrance elevation. At basement level of this turret there is a segmental brick arched open doorway leading into a vaulted chamber with an earthen floor; a narrow flight of stone steps at the rear is blocked off at the top. A number of truncated basalt rubble cross walls project from the rear wall at basement level, the remains of an adjacent basement area that has either fallen into ruin or forms part of an unfinished rebuilding of the main house.

The end elevation facing north-east is single-storey and three-bay, consisting of a central segmental arched entrance recess containing a semi-circular arched doorway flanked on each side by taller semi-circular arched recesses. The construction is of brickwork except for the upper portions, which are of basalt rubble surmounted by stone crenellations. The doorway contains a pair of rectangular two-panel timber double doors surmounted by a two-pane semi-circular fanlight. Three cast iron downpipes drain from concealed gutters. This elevation was originally intended to be an internal wall surface, forming part of the unfinished suite of new rooms planned along the south front of the castle. It now faces into a rectangular enclosure that leads on to other rooms laid out with internal doorways on axis with this one; the enclosing walls range from sill height to mid-storey height.

The building stands at the rear of a gravelled early 19th century battlemented terrace overlooking Lough Neagh. The ruins of an 18th century country house lie to the rear, and the unfinished ruins of the early 19th century country-house extensions are attached to one side.

The conservatory was designed by Nash as part of a broader scheme of additions to Shane's Castle that also included a battery and the terrace on which the conservatory stands, both of which were completed. A suite of rooms intended to provide a southern aspect to the old castle was begun but left in an unfinished state after work was abandoned in 1816 following a fire that destroyed the old castle. By the 1830s the building was described as stocked with rare exotic plants as well as notably fine orange and lemon trees, and as presenting a handsome front of thirteen Saxon windows. Camellias have been grown here from approximately the 1870s, and the building has been known as the Camellia House since at least 1970. The design is reportedly similar to the long conservatory Nash built for himself at East Cowes Castle on the Isle of Wight, begun in 1798. The building stands within the area of an ancient monument.