Peter Gibbs and the panel are at Highclere Castle for a correspondence edition of the show. Chris Beardshaw, Pippa Greenwood and Matt Biggs answer questions sent in by post, email and social media. This week, the panellists tackle questions on a mysterious Brussel Sprout killer, re-potting a large cactus, and an unusually colourful Wisteria. They also recommend climbing plants for a conservatory and discuss how to create a green driveway. In among the questions, the team wanders through the gardens of Highclere Castle with Lady Carnarvon and head gardener, Paul Barker. Producer: Darby Dorras Assistant Producer: Rosie Merotra A Somethin' Else production for BBC Radio 4