As the growing season picks up a pace, Monty is sowing vegetables and planting out the scented plants which he brought back from the Malvern Spring Festival. Carol is delving into the hedgerows and rooting at the bases of walls, fences and trees as she begins her journey to investigate why plants thrive in challenging conditions and we return to Sissinghurst to find out about the changes Troy Scott-Smith is making to the world famous white garden.