In subsequent years he became a collector for Sargent at the Arnold Arboretum, and made further expeditions to China in 1907, 1908, and 1910, as well as to Japan (1911–1916), where he collected 63 named forms of cherry blossom.
Over the following years, he served as a collector for Sargent at the Arnold Arboretum; in 1907, 1908, and 1910, and from 1911 to 1916, he conducted additional expeditions to China and Japan. During these journeys, he gathered 63 distinct forms of cherry blossom.