The quantitative data were not suitable for meta-analysis, as the study designs lacked appropriate control groups and the data from the 2 comparable randomized controlled trials (RCTs) on the garden intervention would have had limited generalizability. Therefore, the quantitative data were tabulated and summarized narratively. A process of thematic analysis was used to synthesize across the qualitative studies, as they were largely descriptive in

nature with little additional interpretation of findings. Data in the form of quotes (first-order concepts) and themes and concepts identified by the study authors (second-order concepts) were extracted. The articles and the extracted data were read and re-read and the findings organized into third-order concepts by the

reviewers. We have TSA HDAC chemical structure used participant quotes to illustrate the concepts in the synthesis. The electronic searches identified 1295 articles of which 85 were retrieved as full text. Seventeen studies met the inclusion criteria (see Figure 1 for reasons for exclusion): 9 quantitative, 7 qualitative, and 1 mixed methods. Fourteen included articles reported on gardens, 3 reported on horticultural therapy, Ibrutinib order and 1 reported on both interventions16 (Supplementary Table 1). The description of the interventions was generally poor in all studies, lacking detail of the garden designs and the nature of resident engagement. One garden second was designed with specific characteristics, such as memory boxes, continuous wandering paths, scented but nontoxic plants, and viewing platforms, to enhance the experience of residents with dementia.17 The remaining gardens were not specifically designed for residents with dementia but contained features such as a mixture of grass, concrete, and decking; raised beds (of flowers or vegetables); gazebos; fish ponds; and benches (Supplementary Table 2). In some studies, residents were allowed to be in the garden for only approximately 30 minutes per day18 and 19 accompanied by nursing home staff or a researcher, with the doors to the garden otherwise locked. In other

studies, residents were allowed to wander unaccompanied17, 18, 20 and 21 and in some it was unclear if the residents were accompanied or not.16, 22, 23, 24, 25, 26 and 27 The components of horticultural therapy varied across the studies in structure, duration, content, frequency, and length of follow-up. Therapy sessions varied from 30 minutes to approximately 1 hour per day, were one-to-one or group based, and were followed-up from 2 to 78 weeks. Sessions involved activities such as seeding, planting and flower arranging, singing, and making jam. Details of the personnel running the sessions were provided in only one study,28 in which a specialized horticultural therapist was involved (Supplementary Table 2).