Monty welcomes a special guest, the Duchess of Cornwall, to Longmeadow, where she shares her love of gardening.Also in this programme, Monty carries out some seasonal maintenance on the mound, demonstrates how to plant a fragrant lavender hedge and catches up on the progress of his aubergines and chillies in the greenhouse.Nick Bailey visits Knoll Gardens in Dorset and gives his tips on the tall perennials which give a burst of colour in borders towards the end of the season, when other flowers have started to fade. JJ Chalmers heads to the Royal Botanic Garden Edinburgh and discovers the vital role it plays in the local community. And we get plenty of inspiration and tips from our viewers' own gardens.