Charlie Dimmock , Tommy Walsh , Kirsty King and Will Shanahan face their last ever challenge. The team have three days to transform an empty plot outside the British Museum into a horticultural project symbolising Africa's diversity. The planting is to reflect the desert lands of North Africa, the Tropics and the temperate regions to the south, while a water sculpture by Sokari Douglas Camp captures the continent's vibrancy and drama.
Producer John Thornicroft ; Executive producer Carol Haslam
Postponed from 7 July Alan Titchmarsh 's 30-minute Gardener: page 37; Amaryllis belladonna and border penstemons offers: page 38