It is not known exactly when this 800-metre-long yew hedge was planted, but photos taken before the First World War prove that it was much smaller and more regular in shape until the early 20th century.

The topiary yew hedge requires cutting at least once a year, and it seems that it may have run wild during the First World War when no men were available to cut it. Since then, the irregularly organic and undulating curves of the hedge have been kept; this form is sometimes referred to as a "cloud hedge".

Other examples of this organic and undulating form of cloud hedge can be seen at Audley End near Saffron Walden, and Walmer Castle in Kent, where the shape of the hedges is also thought to have resulted from a lack of pruning during the World Wars. Powis and Rockingham Castles also have fine examples.

Topiary, or the horticultural practice of training plants by clipping, is thought to have originated in classical antiquity — in Roman times. Yew is an ideal plant for topiarising.