Landscaping of the South Eastern University of Sri Lanka faces problem in achieving its standard quality due to, environmental challenges lack of planning and resource allocation. In order to improve the landscaping activities by adopting with ISO 21500:2021 project planning and portfolio Management-Concepts and practices were suggested as an appropriate practice. ISO 21500:2021 is a systematic method used in project planning and implementation. The objective of this study is to create improved lawn maintenance and landscaping method using ISO 21500:2021. In order to succeed in this project total landscaping area were divided into eight manageable plots and resources were reallocated in a way to attain the completion of grass cut and landscape cycle within a specified period. Accelerated process can be incorporated accordance with time to time requirements. According to the identified critical path and non-Critical path, the resources were allocated and used in optimum level. The cycle time has been reduced and the quality output has been achieved.