Monty Don gets going on a new project as he begins planting a colour-themed, fragrant border and he offers on successional planting in the vegetable garden. Nick Bailey begins his ultimate guide to growing clematis, while Arit Anderson visits a new, free, public roof garden in London, which soars above the city space below. Plus, Carol Klein travels to Arundel Castle in West Sussex where alliums are taking centre stage and Joe Swift finds out about the restoration of one of country's most historic woodland gardens.