Garden is a kind of landscape with plant designing as the main form.When designing a garden,plant morphology is the first factor to be considered,however,there is a lack of research on garden plant morphology.Based on the former research and the closure principle of Gestalt theory,we simplified,classified and refined the common garden plant forms,and summarized them into 5 primary forms according to geometric forms:round,cone,square,mound and other shapes.Combined with specific forms,we further subdivided 14 secondary forms,and established a garden plant form classification framework,we also summarized the representative plant and application characteristics of each form.Simultaneously,we conducted an in-depth analysis of exemplary practical cases,based on three primary types of garden plant combinations:herbaceous,woody,and a mixture of both.We also synthesized the principles of combining diverse plant forms and integrated the classification framework for garden plant forms into the design process.This study aims to provide new ideas and basis for the theory and practice of garden plant design,and to promote the application of formal aesthetics and modular design in the field of garden design.