The Corliss Knapp Engle slide collection contains 35mm slides of gardens, garden features, flower shows, and flora photographed by Corliss Engle, a self-taught photographer and horticulturalist. Much of the collection is comprised of photographic documentation of numerous private and public gardens that she visited throughout the United States. Of particular note are images of Engle's own garden in Brookline, Massachusetts, spanning three decades; they provide excellent insight into the development and evolution of a garden over time. Portions of the collection highlight Engle's involvement with the Garden Club of America and the GCA's Garden History and Design Committee. The collection also includes various notes, lecture scripts, brochures, programs and articles on garden and plant-related themes generated or compiled by Corliss Knapp Engle.

The Lewis & Valentine Company Collection contains records of the Lewis & Valentine Company dating from 1916 to 1971 including photographs, negatives, brochures, books, trade catalogs, company papers, letters from clients, customer lists and a history of the company written by Harold Carman Lewis. Photographs document the Rodin Museum in Philadelphia, estates in Long Island, New York, and the properties of Hugh D. Auchincloss, Eugene du Pont, Walter P. Chrysler, Otto H. Kahn, F. W. Woolworth, Pierre S. du Pont (Longwood Gardens), Charles M. Schwab and Edward T. Stotesbury. This collection contains only a sampling of the records of Lewis & Valentine and should not be considered comprehensive.

The J. Horace McFarland Collection includes over 3,100 photographic images of private and public gardens throughout the United States, as well as some from foreign countries, dating from 1899 to 1963. Many of these images, generated for Mount Pleasant Press (later the J. Horace McFarland Company), were used to illustrate trade catalogs published by the firm as well as journal and newspaper articles. The collection also contains color records that were used as reference aids during the printing process, plant patents, and various publications of the McFarland Company.

The Maida Babson Adams American Garden Collection documents the work of Molly Adams, a free-lance garden photographer who photographed hundreds of private and public gardens, many of them in the mid-Atlantic region, from the late 1950s through the mid-1990s. It includes slides, photographic prints, negatives and transparencies. A significant number of images document the work of landscape designers Nelva M. Weber, Alice Recknagel Ireys, and Friede Stege. Roughly 50 gardens do not have an identified location. Some images have captions and other information written on them.

The Thomas Warren Sears Photograph Collection documents examples of the design work of Thomas Warren Sears (1880-1966), a landscape architect and amateur photographer from Brookline, Massachusetts. Sears, who was based for most of his career in Philadelphia, designed a variety of different types of landscapes ranging from private residences, schools, and playgrounds to parks, cemeteries, and urban housing developments located primarily in Pennsylvania, Maryland, and New York. In addition to some of Sears' design work, images in the collection document Sears' domestic and foreign travels, design inspirations, and family. The collection includes over 4,800 black and white negatives and glass lantern slides dated circa 1899 to 1930. While most images show private and public gardens, there are a significant number of unidentified views and views photographed in Europe during two trips he took there in 1906 and 1908. Few images are captioned or dated. In addition, there are over 50 plans and drawings, most notably for Balmuckety in Pikesville, Maryland and Reynolda in Winston-Salem, North Carolina, and 3 monographs by or about Sears.

This collection contains over 37,000 35mm slides, 3,000 glass lantern slides and a small number of landscape architectural plans and drawings, all of which document the history of American gardens and landscapes. Garden files were compiled by Garden Club of America (GCA) members for most of the gardens included in the collection. These files may include information sheets, photocopied articles (from journals, newspapers, or books), planting lists, correspondence, brochures and other notes. Some gardens have been photographed over the course of several decades; others only have images from a single point in time. In addition to images of American gardens, there are glass lantern slides of the New York Flower Show (1941-1951) and trips that GCA members took to other countries, including Mexico (1937), Italy, Spain, Japan (1935), France (1936), England (1929), and Scotland.