This research examines the impact of VR/AR-enhanced representations on Design Communication (DC) between professional landscape designers and other consultants involved in real-world design practices. Fourteen experienced landscape designers and design consultants are invited as participants and work on two different projects for six weeks. One group of them uses traditional design representation methods to support their work while the other group adopts both traditional approaches and VR/AR-enhanced representations. Surveys and in-depth interviews are arranged to understand their design perception, design cognition, and experience in overall DC process during the project phase of site analysis, concept initiation, and design development. In this way, the impacts of VR/AR technologies and project phase on DC among professional LA designers and other design consultants can be discussed. The findings indicate that VR/AR-enhanced design representations can significantly improve design perception of design details but show no obvious impacts on design cognition. VR/AR technologies also enhance the cross-disciplinary collaboration and reduce conflicts by providing immersive, interactive, and enjoyable DC experience for multidisciplinary designers. Overall, this research explores the potential of immersive technologies to improve DC in complex, collaborative, and practical LA projects, suggesting approaches to optimizing conventional design practice workflows and representation methods in landscape architecture.