Research shows that contact with nature plays a vital role in our psychological wellbeing. Domestic gardening is common among older adults who spend more leisure hours gardening than any other age group. Despite this, few studies have systematically explored the significance of domestic gardens in relation to older adults' health and wellbeing. This study examined the perceived therapeutic benefits of gardening, and the effect of ageing in relation to older gardeners' continued participation in gardening, using quantitative and qualitative data from a survey of Australian older adult gardeners (N=331). The quantitative data, which included frequencies, were analysed using the PASW Statistics 18.0 package. The qualitative data, which included participants' responses to open questions, were analysed by deriving themes via Leximancer, an innovative text analytics software that uses word association information to elicit concepts, extracting the most important and grouping these according to themes. In relation to the reasons for gardening, several themes were identified including valuing the aesthetics of gardens, connecting with nature, achievement, and physical and mental activity. The benefits of gardening, and the variety of ways that respondents had adapted or modified their gardening activities in order to continue, are also reported. Gardening was more than a casual leisure pursuit for these participants, who saw it as critical to their physical and psychological wellbeing.