A survey of the introduction of <i>Rhododendron</i> from China to the United States during 1898-2023.

The United States has conducted extensive plant introduction activities worldwide since the 19th century. <i>Rhododendron</i> species received particular attention due to their high ornamental value. In the 20th century, the United States focused particularly on <i>Rhododendron</i> resources in China. To clarify the history of the introduction of <i>Rhododendron</i> from China to the United States, we compiled historical records to trace the history of American <i>Rhododendron</i> introductions from China between 1898 and 2023, and verified the botanical names, introduction times, locations, and collectors. The results showed that a total of 1406 records of American <i>Rhododendron</i> introductions from China were compiled, including 215 species (including 27 varieties and 12 subspecies), which accounted for 29.5% of the total number of <i>Rhododendron</i> species in China. The introduction activities covered 20 provincial administrative regions, and 10 collectors were involved, with Wilson and Rock standing out for their significant contributions. The American introductions of <i>Rhododendron</i> from China enriched the diversity of <i>Rhododendron</i> species in the United States and enhancing their application in American gardens.