Weeds and Aliens (Collins New Naturalist Library, Book 43)How and why a well managed garden plant or an introduction from abroad will suddenly become an aggressive weed. This edition is exclusive to newnaturalists. com This long awaited book is more than a key volume in the New Naturalist series: it is a work of the first importance by the leading authority on the subject. For though Sir Edward Salisbury is best known to the public for his thirteen years' work as Director of Kew, and for his outstandingly