Monty starts his plans for his revamped courtyard garden when he plants bare root trees and gives advice on climbers which will thrive on east-facing walls. Nick Bailey explores the strange world of lichens and finds out how these plants grow and thrive on trees, wood and stone, and Frances Tophill meets the enthusiastic gardeners of Barbados who fill their gardens, however small, with colour, foliage and world-class flowers. And as part of the programmes 50th anniversary, Flo Headlam reveals the plant she thinks has had the most impact on British gardens over the last half century.