It is clear that many thousands of species are at present vulnerable or endangered by human activities (Frankel & Soulé, 1981; Primack, 1993, 2010; Given, 1994; Meffe & Carroll, 1994; Frankel, Brown & Burdon, 1995). Broadly, two conservation options are available. Plants may either be conserved ex situ, in such places as Botanic Gardens, or in situ in their native habitats. Here we consider, briefly, the early history of conservation, and how theory and practice have changed – from protection, management, to reintroduction/restoration and creative conservation.

Ex situ conservation

Endangered species, including those at the very edge of extinction, are often conserved ex situ in Botanic Gardens and arboreta (Briggs, 2009; Hardwick et al., 2011), of which there now more than 2700 worldwide (Ali & Trivedi, 2011). The scale of the holdings of Botanic Gardens is impressive: perhaps 25–30% of all vascular plants are represented in the collections (Wyse Jackson & Sutherland, 2000). Some gardens hold very large general collections (e.g. Kew with c.10% of the world's plants), while others have specialist collections (e.g. The Arnold Arboretum, Boston, USA, grows several hundred species of temperate tree). Botanic Gardens Conservation International (BGCI), Richmond, England, organises and coordinates the conservation efforts of gardens (www.bgci.org/). Regrettably, most Botanic Gardens are located in temperate areas of the world, and it is costly to grow tropical plants in the glasshouses of Europe and North America. However, there are some notable Botanic Gardens in the tropics (Heywood & Wyse Jackson, 1991), and, if the number could be increased, it would be possible to conserve many tropical species of plants cheaply out of doors, and provide important centres for economic development and exploitation of plant biodiversity.

Other specialist gardens also play a key role in ex situ conservation. In England, the National Trust has now relocated its conservation activities from Knightshayes Court, Devon. It was necessary to move to another site because of an outbreak of Sudden Oak Death (caused by the fungus Phytophthora ramorum). The new ex situ facilities are designed to secure the future of the rare and endangered plant species that grow in the Trust's ‘200 gardens, 100 landscape parks’ and ‘in the many wild places it manages’ (Morris, 2012).