While the authors are primarily researchers and other plant professionals, all are encouraged to write with a narrative and explanatory style that is accessible to a wide range of readers.

Other than the addition of illustrations, however, the publication continued to be a seasonal guide filled with information on the phenology, history, and culture of the Arboretum's plants.

Edgar Anderson, best known for his later work at the Missouri Botanical Garden, edited the publication for the next four years, and while "plants of current interest" remained a regular feature, staff members began to contribute longer articles, with new interdisciplinary topics including ethnobotanical uses of plants, botanical art, and landscape history.

[2] This thematic expansion was encouraged by Oakes Ames, a Harvard professor of botany who had been appointed the managing supervisor of the Arnold Arboretum in 1927.

[4] A remembrance in 1993 recognized his contributions: "More, perhaps, than any other single person, certainly of his era, he advanced the knowledge of hardy woody plants through his articles published in Arnoldia and elsewhere .