ABSTRACT. Private gardens collectively comprise the largest green space in most cities and the greatest potential for increasing the extent of wildlife-friendly and native-dominated habitat, improving the quality of ecosystem services, and providing opportunities for urban dwellers to reconnect with nature. Because attitudes and values driving landscape preferences in gardens are complex and often not conducive to biodiversity, and a gap exists between the possession of knowledge or values and the expression of pro-environmental behavior, facilitating change in gardening behavior is challenging. We attempted to improve knowledge and influence values, attitudes, and gardening behavior of 55 householders in favor of native biodiversity and environmentally friendly practices, through a two-way communication process, or interactive dialog, during a process of biodiversity documentation of their gardens. Informative feedback on their garden with a normative component was also provided. Despite being well educated and knowledgeable about common species at the start of the study, an increase in knowledge and shift in attitude was detected in 64% of householders: 40% reported a greater understanding of wildlife, and 26% made changes in their gardens, 13% to support native biodiversity. The normative component of our feedback information was of particular interest to 20% of householders. Because neighborhood norms influence gardening practices, changes adopted by a proportion of householders should be perpetuated across neighborhoods. The process of biodiversity assessment, dialog, and feedback was effective in improving knowledge of wildlife and native species, and stimulated a shift in attitude that resulted in native-friendly gardening practices. These changes were detected primarily through open self-report questions, rather than quantitative measures.