The Historic Gardens Stereograph Collection includes 807 stereographs that depict various public gardens, parks, and tourist attractions throughout the United States, with an emphasis on features related to horticulture and landscape design, including plants, garden furniture, and topiaries. Most, but not all views, show exterior features. A number of stereographs indicate the photography studio on the recto or verso, as well as a series or image number. Many include a brief caption; some include a lengthy description on the verso. Few are dated.

The Historic Gardens Postcard Collection includes 200 postcards of historic views of various public gardens, parks, monuments, and buildings throughout the United States and some foreign countries, including Canada, France and Cuba. Some private gardens and estates and many Washington, D.C. attractions are also represented. Roughly half of the postcards were mailed; the remaining postcards were not written on or posted. Areas represented include Arizona, California, Colorado, Delaware, Florida, Illinois, Indiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Nebraska, New Jersey, New York, Ohio, Oregon, Pennsylvania, Texas and Virginia. Foreign views show gardens in Havana, Paris, and Canada. About a dozen cards feature various views of Smithsonian Institution museums along the National Mall in Washington, D.C.

This collection contains over 37,000 35mm slides, 3,000 glass lantern slides and garden files that may include descriptive information, photocopied articles (from journals, newspapers, or books), planting lists, correspondence, brochures, landscape plans and drawings. Garden files were compiled by Garden Club of America (GCA) members for most of the gardens included in the collection. 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. A number of the slides are copies of historic images from outside repositories including horticultural and historical societies or from horticultural books and publications. The GCA made a concerted effort in the mid-1980s to acquire these images in order to increase its documentation of American garden history. Because of copyright considerations, use of these particular images may be restricted.

The American gardens collection, a component of the Archives of American Gardens (AAG), includes holdings not associated with other major collections in the archives. The slides, photographs, plans, and files in this collection come from various private donors. Individual sub-units typically depict a single garden.

The Hollerith Family Collection includes approximately 2,200 35mm slides dating from 1952 to 1980 that document the horticultural interests and travels of sisters Virginia and Nan Hollerith, members of the Georgetown Garden Club in Washington, D.C. The images primarily show private and public gardens, plantations, and historic sites in the mid-Atlantic and the southeast regions of the United States. Included in the collection are slides documenting the activities of the Georgetown Garden Club and various floral arrangements.

The Lois W. Poinier Collection documents the work of Lois W. Poinier, a self-taught garden designer who designed scores of gardens, most of them in New Jersey.

The Frederic H. Leubuscher Collection contains 106 duplicate 35mm slides documenting examples of Leubuscher's landscape architecture design work in New Jersey, New York, North Carolina, Rhode Island and other locations.

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 Mildred N. Beauregard Slide Collection contains 1,249 35mm slides, dated circa 1947-1971, of gardens and castles in England, Scotland, France, Holland, Switzerland, Sweden, Norway, and Denmark, as well as American gardens, photographed by Mildred Napier Beauregard. Some slides show tourist sites and scenes including skylines, rock features, waterways, boats and ships, and unidentified individuals. The collection also includes two slide viewers.

The Ken Druse Garden Photography Collection contains approximately 45,000 film transparency and 35mm slide images, dating from 1978 to 2005, of gardens, garden features, and flora photographed by garden writer and photographer Ken Druse. The photographic images document numerous private and public gardens throughout the United States and a few in Canada. Many have appeared in Druse's own books and articles as well as those by other writers. Approximately half of the collection is arranged according to specific garden, the other half by garden feature. A small portion of the collection consists of slide lectures given by Druse. Some images are identified with general captions and dates. Images documenting specific gardens are sometimes accompanied by handwritten notes, garden descriptions, and articles. Annotations appearing on certain images indicate the publication in which they appeared. The collection includes 'outtakes' or bracketed images that give insight into Druse's photo shooting process.