United States Botanic Garden(USBG) was taken for example to systematically demonstrate the role of formal composition in garden landscape design.Application cases were used to analyze formal composition of plant landscapes in USBG.Point plant landscapes lay the foundation of all other forms,concentrated and centripetal effects of which can form comparisons according to size of plant.Line is the trace of moving points,and linear plant landscapes indicate those formed by using thick,thin,long,short,square,round,curved and straight "lines".And surface plant landscapes are to form contrastive images or scenic areas by using plant clusters.Finally,concrete cases were given to analyze flowerpot selection and combination for creating point,linear and surface potted plant landscapes,and to provide detailed reference for the plant design of modern Chinese gardens.
