This study aims to identify the key drivers of two garden-related environmental behaviors (GEBs): plant choice and bush-friendly behavior. This is important for biodiversity conservation threatened by weed invasion from domestic gardens. The effects of self-control, time pressure, and knowledge of weed-control initiatives were examined. A mail survey was sent to suburban residents living adjacent to native bushland in Wollongong, New South Wales. Regression analysis and structural equation modeling (SEM) were used. The path models for SEM were based on the theory of reasoned action. The results indicate that attitude, perceived harm, and knowledge of weed-control initiatives exert an effect on GEBs through intention; self-control influences intention to increase native garden plants; and time pressure influences bush-friendly behavior. The results emphasize the importance of searching for predictors that are specifically related to the examined behavior instead of only relying on a universal model to explain behavior. Behavior-intervention strategies for weed management are derived.