Landholder adoption of conservation practices has been extensively researched in dryland areas, but there has been less research into the adoption of biodiversity conservation in irrigation areas. The Murray Catchment Management Authority (MCMA) and Murray Irrigation Limited (MIL) in south-west NSW offer landholders monetary incentives to enhance native vegetation management. However, uptake of the incentives and recommended practices has been slower in the irrigation areas than in dryland areas serviced by the MCMA. We explored landholder participation in native vegetation management in the MIL area using semi-structured interviews with landholders and extension staff. Our findings suggest there are important differences between irrigation and dryland contexts. Landholders in irrigation districts face higher opportunity-costs and are more likely to mistrust government intentions. Other constraints to adoption include lack of financial resources and time to carry out works and a high turnover of extension staff. Landholders adopted recommended vegetation management practices because those practices matched their values and goals. The importance of regular contact with a positive and enthusiastic extension officer was also evident. These findings have important implications for conservation policies and programs. Extension should move beyond arousing interest and include substantial follow-up contact to maintain landholder motivation and confidence, as well as provide recognition for past landholder efforts. Incentive programs should be designed to provide wider landholder support with different entry points allowing participants to adapt, learn and build confidence. Incentives should address the constraints experienced by landholders, particularly at times of peak workloads and during drought. Work targets set for field staff can be too high and result in program staff focusing on accomplishing on-ground work, rather than developing irrigators’ longer-term commitment to vegetation conservation.