The rapid development of generative artificial intelligence (AI) technology is changing many fields. Accordingly, this study focused on ways to utilize basic generative text-to-image AI tools in the landscape design process with the aim to save time in the existing design study process. We compared three AI tools, Midjourney, Synthesys X, and Playground AI, using three prompts and determined that they have different advantages regarding the individual landscape elements. We identified which AI tool showed the highest score for each landscape element and the highest overall score. Synthesys X was found to perform well in paving and Midjourney in tree shape. In creating the desired space shape, Synthesys X and Playground AI showed strength. Thus, our study provides guidelines for the use of the various AI tools in the design study process.