As summer weather arrives, David visits Cherry Townsend at Kilcoan Gardens in Islandmagee, where she has a brilliant collection of flowering plants that bridge the gap between spring and summer. Geums, Trollius, Aquilegia and Tellima are among the highlights in the borders. One of the biggest gardens in London is found across the river from Westminster behind the walls of Lambeth Palace. It’s the home of the Archbishop of Canterbury but the 10 acre garden is opening for the National Garden Scheme later this month and head gardener Lindsay Schuman gives David a sneak peek. Gordon Finch joins David in studio to talk about his fascination with ferns and restarting the local group of the British Pteridological society. Robot mowers have been gaining in popularity – producer Nicola chats about her experience with one she has nicknamed ‘Mervyn’. And Oliver Shurmann reveals his perennial of the month. In studio, Anna Hudson will be chatting about her veg patch at Ballywalter and she’ll take questions live in studio. Contact the programme gardenerscorner@bbc.co.uk