Summer-house & Walled Garden with Ha-ha and Gate Piers at Trevor Hall

The summer-house and walled garden at Trevor Hall date back to the 18th century. The summer-house is located in the southwest corner of a walled enclosure, which is bordered on the south side by a ha-ha. It is a small pavilion designed in the Georgian style, featuring a low, three-centred arch made of ashlared stone with impost capitals, and it is open to the east front. The outer piers are also made of ashlar and topped with ball finials, connected by a moulded cornice above a rubble stone spandrel. The roof is a patterned tiled lean-to with a coped gable at the rear.

Attached to the summer-house is a high boundary wall made of rubble stone, which was originally the orchard wall. This wall has flat copings and runs west to the rear, featuring a single arched opening. It then returns uphill to the right, meeting a red brick north wall that extends back towards the main house.

To the east of the summer-house, there is a masonry ha-ha topped with ironwork railings. This ha-ha connects to a garden boundary wall that runs north and then returns inward to meet twin rusticated gate piers, also topped with ball finials, at the entrance to the driveway.

Inside the summer-house, there is a high-backed, curved timber seat. The plaster ceiling is noted to be in poor condition as of the last inspection in March 1997.