Urban greenspaces are public spaces, fulfilling multiple city functions, such as improvement of public health. They are also ecosystems which provide biodiversity as part of the green infrastructure. To evaluate greenspaces as ecosystems, seventeen urban greenspaces in Yokohama, Japan, were selected to conduct surveys of flora and construct a vegetation table. The present study investigated the number of woody plant species; their growth form (tree, shrub, or liana); the ratio of evergreen to deciduous plants; and whether plant species were native, exotic, wild, or planted. The greenspaces were compared with the control area, Enkaizan, a suburban greenspace within Yokohama and representative of Satoyama (a traditional landscape model with sustainable living space). The comparison used cluster analysis to match the correlation of identified species in each greenspace and split them into four groups: (1) natural, (2) quasi-natural, (3) quasi-artificial, and (4) artificial. The study found the natural greenspace group to have an intact hierarchical forest structure with trees, shrubs, and lianas; whereas artificial greenspaces missed either tree or shrub layers and had few lianas. The more artificial greenspaces had higher proportions of exotic and evergreen species.