The mountains and moorlands marking the borders of England and Wales are carved up by wooded river valleys, verdant farmlands and a rich seam of outstanding and highly regarded private gardens.

Country Life’s tailor-made, exclusive tour, in the soft light and residual warmth of mid September, will be hosted by Helena Attlee, the engaging author of The Gardens of Wales, who has lived in the region for many years.

From the relaxing comfort of our base at Gliffaes Country House Hotel, we will venture forth to a stimulating collection of private gardens, including Brilley Court, surrounding a 16th-century farmhouse, the plantsman’s paradise of Lower House on the edge of Hay-on-Wye, atmospheric Llowes Court and Sir Roy Strong’s reworked garden at The Laskett.

Medieval Allt-y-Bela, with its ochre render, is the home of garden designer Arne Maynard and Brockhampton Cottage has a hillside garden by Tom Stuart-Smith. At Wyndcliffe Court and High Glanau Manor, we find a pair of superbly restored Arts-and-Crafts gardens connected with H. Avray Tipping, who was famously Country Life’s architectural historian in the formative decades of the early 20th century.

Run by garden-holiday specialist Boxwood Tours, our borderland sojourn runs from September 14 to 18 and costs £2,348 per person (01341 241717; www.boxwoodtours.co.uk).