Eerie figures sculpted from yew have entranced visitors to the famous Mount Stewart gardens for decades.
And it looks like they are now a key element in the battle against cancer, according to the National Trust.
The topiary figures, under a painstaking regime of clipping to keep them in shape, are inspired by creatures from Celtic myth and historical symbols representing Northern Ireland.
Those surrounding the shaped hedge around the Shamrock Garden tell the story of how the Stewart family arrived in Ulster from Scotland to hunt for a stag.
Until now, those mountains of yew clippings were destined for the compost heap – but it turns out they have a vital role to play in the fight against cancer.
Limehurst Ltd, which specialises in the harvesting of medicinal plants, is now collecting Mount Stewart's yew clippings for the manufacture of anti-cancer treatment drugs paclitaxel (Taxol) and docetaxel (Taxotere). The common yew contains an enzyme which can be processed and used to reduce tumor size and facilitate surgery. Artificial synthesis has so far proved elusive and the only source is from varieties of yew.
Peter Talbot of Limehurst Ltd, who collects the clippings, said: "Limehurst has been harvesting plants in the mainland for use in medicine for 20 years, but the operation in this part of the UK only started recently.
"The National Trust does great work in preserving our heritage and it's great to see such an outstanding level of craftsmanship in the topiary here. We are delighted that the conservation charity is collecting their yew clippings at Mount Stewart to help us in this important work."
James Dorrian, the gardener responsible for Mount Stewart's topiary, said: "My uncle Terry created much of the iron framework for the topiary. It's great to think that years later I'm involved in helping maintain and fine-tune these fantastic pieces.
"Visitors are often telling me that the topiary at Mount Stewart is unique in that it tells a story. Now we can also tell the story of how the clippings are used to create such an important medicine."