As the last days of summer start to fade and autumn takes hold, it is time to start planning ahead for next year. At Longmeadow, Monty Don adds some foxtail lilies to his dry garden for a touch of drama in May and June. Carol Klein is in Kent visiting salvia expert William Dyson to find out where these exquisite plants come from, how many colours there are to choose from and what they need to thrive in the UK. And we meet a remarkable woman from a family of gardeners on the eve of her 100th birthday.