Monty Don and the team celebrate the start of summer as they indulge in the stunning array of colour and scent beginning to take over our gardens. Carol Klein continues her celebration of great plants and the people who champion them. In this episode she's at Glendoick near Perth enjoying their wonderful collection of flamboyant rhododendrons. Joe Swift visits world-renowned opera venue Glyndebourne in Sussex. He meets the head gardener, and is given an exclusive, behind-the-scenes tour of their gardens only days before the opera season begins and the gates open to the public.