Agri-environment schemes (AESs) in England typically address environmental management at the farm- and field-scales, but there is increasing evidence that incorporating the landscape-scale would increase scheme effectiveness. Lessons on incentivising collaboration across farm boundaries are drawn from telephone interviews with holders of 18 Environmental Stewardship Scheme (ESS) agreements containing the Higher Level Stewardship (HLS) option HR8; “Supplement for Group Action”. This option is more likely to be included when (i) the ESS agreement replaces a previous AES agreement and when (ii) negotiations are assisted by an external organisation. The large degree of flexibility HR8 contracts are allowed is essential to successfully address the wide range of site-specific contractual problems encountered. The number of stakeholders and their range of interests, rather than the land area covered by the agreement are the major determinants of transaction costs on large-area agreements. Although most commonly used in upland moorland agreements, the use of HR8 in lowland agreements shows great inventiveness and demonstrates the potential for extending the use of boundary-spanning options. Suggestions are presented for developing boundary-spanning management options and for incentivising collaborative conservation through a revised ESS.