The need for action on the global environment is now well understood and governments, agencies, non-governmental organizations and botanic gardens have all been working in their various ways to promote environmental sustainability and reduce species and habitat loss for at least 10–20 years. The Global Strategy for Plant Conservation (GSPC) has been widely adopted, particularly by the botanic garden community, and has resulted in many successes despite failing to achieve its ultimate goal of halting the loss of plant biodiversity. The objectives and targets for Phase 2 of the GSPC, running from 2010 to 2020, mirror those of Phase 1 and had been largely agreed prior to their formal adoption at the Conference of the Parties to the Convention on Biological Diversity in Nagoya in October 2010. However, to be successful, the scientific contribution of botanic gardens needs to be strengthened, as does government policy and commitment. Botanic garden research to underpin conservation action, including the role of botanic garden horticulture, training and international capacity building, has a major part to play and needs to be better understood and better coordinated. We provide examples based on the experience of the Royal Botanic Garden Edinburgh in the UK and overseas. Government policy, at national and international levels, needs to reflect the fundamental importance of plant diversity in maintaining the biosphere and supporting humanity. The commitment of significant new resources is an essential prerequisite for success, but this needs to be well coordinated, inclusive of all stakeholders and carefully targeted. A further challenge is the need to integrate better the plant diversity-related activities of what are currently diverse and disconnected sectors, including agriculture, forestry, protected area management and botanic gardens.