Andy Clayden is a landscape architect, garden designer, and a lecturer at the University of Sheffield, England.

Nigel Dunnett is a Reader in Urban Horticulture in the landscape department at the University of Sheffield, where he has developed innovative research programs on naturalistic and ecologically informed planting for gardens and public landscapes. He is director of The Green Roof Centre, Sheffield, and acts widely as a consultant on green roof design and planting, and sustainable garden and landscape design in general.

He writes regularly for landscape and garden publications, including Gardens Illustrated and The Garden. With Noël Kingsbury he wrote Planting Green Roofs and Living Walls; with Andy Clayden, Rain Gardens: Managing Water Sustainably in the Garden and Designed Landscape.