I would like to extend my thanks to everyone who has supported my research so far. Without your generous support this work would not have been possible: Dr. Greg Kenicer, Rafaela Trad, Kirsty Wilson, and all the staff at RBGE, Opal Rowe, Ruth Vichos and Jonathan Starkey from SRUC, Cambrige University Botanic Garden, Oxford Botanic Garden, Joe Richomme and the Royal Botanic Garden Kew, Glasgow Botanic Garden, John David, Kalman Konyves and the Royal Horticultural Society, including the RHS Bursaries Committee, Kelly Dodson and Sue Milliken of Far Reaches Farm and Far Reaches Botanical Conservancy, Tim Fuller of The Plantsman’s Preference, Kevin Hughes of Cally Gardens, Joe Sharman of Monksilver Nursery, Hans and Miranda Kramer of Kwekerij de Hessenhof, Robert Herman formerly of the Gräfin von Zeppelin Nursery, Nick Macer of Pan Global Plants, Bob Brown of Cotswold Garden Flowers, Christopher Hallsworth former National Collection Holder, Benita and Irisa Branaburga, Kristina Scheller and the Karl Foerster Garten, Steve Marshall and the staff at Beth Chatto Plants and Gardens, Brendan Sayers and the Irish Garden Plant Society, Hardy Plant Society, Dr. Konrad Näser, Annemarie Eskuche, Anne Repnow, Alan Furness, and most of all to my friends and family. Special thanks to John Fielding, Gareth Stanfield and Nick Wood.