<p>Peter Gibbs and the GQT panel have traded parks and community gardens for a visit to the Oxfordshire home of Dame Mary Berry. On this week's panel are Matthew Pottage, Christine Walkden and Bunny Guinness.</p><p>Among today’s questions, the panellists troubleshoot evergreen roses plagued by black spot, unravel the mystery of why clematis keep failing on one side of a small London garden, and help a listener planning a late‑August wedding by suggesting plants that peak at the tail end of summer.</p><p>Later in the programme, Mary shares her own gardening triumphs, from peaches ripened under winter covers, to treasured raised beds of herbs, strawberries and asparagus.</p><p>Producer: Dan Cocker Assistant Producer: William Norton Producer: Matt Smith</p><p>A Somethin' Else production for BBC Radio 4</p>