The Manor House, Ayot St Lawrence, Hertfordshire. May 21–22, 11am–5pm

An outstanding six-acre garden around a delightful Elizabethan manor house (not open), designed for the present owners by Julie Toll. Memorable features include an immaculate parterre, borders of yellow bearded iris and a burgeoning one-acre walled garden complete with glasshouses, fruit and veg (www.ngs.org.uk)