Alien plant invasion causes both economic and environmental damages severely, and then it has been recognized as a worldwide issue. In terms of invasive flora, species composition or major life form of those invasive plant species looks different between countries and/or regions. Major source of alien invasive plant is garden escape typically in Oceania countries, and officially declared invasive species are mainly escaped garden plant in those countries, which includes perennial herb, tree/shrub or vine species. For example, in New Zealand, about three-quarters (74%) of terrestrial weeds were deliberately introduced as ornamental garden plants, with a further 14% deliberately introduced for agriculture, commercial horticulture or forestry (Owen 1998). Only 10% were introduced accidentally as contaminants with soil, animals or other plants. Japanese invasive flora is contrast to those countries. In the list of officially declared invasives, ca. 70% of invasive plants are grass or herbaceous species. Moreover, many of them are annual and unintentionally introduced to Japan, and only 20% of plants in the list are recognized as garden escape (excluding aquatic plant). In this presentation, I would like to discuss about the reason of the difference, based on FAO trading data and the invasive plant lists of Japan, New Zealand and east coast of the United States.