This study analyzed import quarantine statistics from the Animal and Plant Quarantine Agency and catalog data from three major importers between 2014 and 2023 to examine the scale, composition, and supply structure of foreign landscape woody plants (cultivated varieties) imported into Korea. Over the past decade, Korea's import market for landscaping trees has undergone a structural expansion in both total volume and taxonomic diversity, a trend that contrasts sharply with the stagnation or decline in domestic production since 2017. The top ten genera accounted for 73.5% of the total import volume, indicating a high degree of concentration. Among these, Thuja, Juniperus, Hydrangea, and Paeonia showed a clear upward trend over the past five years, while Hibiscus, Daphne, Acer, and Lagerstroemia exhibited slower growth or a downward shift. At the country level, the supply structure was heavily concentrated, with China and the Netherlands dominating the market. The number of source countries, which temporarily expanded during the COVID-19 pandemic, later re-converged to around 8-10 countries. Dependency analysis by genus revealed that Buxus, Lagerstroemia, and Daphne were almost exclusively imported from China, whereas Thuja, Juniperus, and Hydrangea were mainly sourced through the Netherlands as a hub country, and Paeonia was supplied jointly from China and Japan. Catalog-based morphological analysis showed that shrubs, broad-leaved species, and deciduous types predominated, with the genus Hydrangea ranking highest in cultivar diversity. Despite this expansion in volume and variety, Korea's foreign landscaping tree market remains structurally vulnerable due to its heavy dependence on a few genera and specific supplier countries. Such concentration heightens the sensitivity of the supply chain to potential disruptions, underscoring the need for diversification and adaptive import strategies.