In their introduction to the Plant Red Data Book of endangered species, Lucas and Synge (1978, 31) concluded: ‘Botanic gardens…are poised to play a major role not only in cultivating the [endangered] plants concerned, but also in their re-introduction, in habitat management and even in owning and maintaining small reserves for particular species.’ Moreover, they predict: ‘once the individual facts on threats, habitats sites and populations are known, successful conservation of most plant species is likely to prove far less difficult and costly than that of animals’. After 30 years, it is timely to review the role of botanic and other gardens in the conservation of endangered species, and to examine current views on these predictions.

The use of the phrase ‘poised to play a major role’ suggests that the use of botanic gardens for the conservation of wild endangered species represented something of a new direction for gardens in the 1970s and 1980s (Lucas & Synge, 1978). For what purposes were botanic gardens founded in the first place, and how have they developed historically? What have theoretical investigations and practical studies revealed of the ‘strengths and weaknesses’ of gardens in their proposed new role? Given the ‘costs’ associated with ex situ conservation, endangered species are generally grown in botanic gardens and arboreta. What are the likely consequences of such cultivation?