In 2031, the National Trust for Scotland will celebrate its 100-year anniversary and, to mark the occasion, it has asked Charlotte Harris and Hugo Bugg of the award-winning Harris Bugg Studio to create a Centenary Garden at one of its most impressive estates. Newhailes House & Gardens in Musselburgh, five miles east of Edinburgh, will get a new three-acre garden within its historic walled enclosure. The space was formerly the estate's Flower Garden, its most ornamental area. The new plans will draw on 200-year-old designs, dating back to a time when Newhailes was home to an independent, curious and progressive woman of the Scottish Enlightenment, Miss Christian Dalrymple. After inheriting the house in 1792, she commissioned horticulturist and garden designer John Hay to create a new garden in the early 1800s, and although it was never built, Hay's drawings survived.…