The archive documents the professional career of southern California landscape architect Emmet Wemple and his firm, Emmet L. Wemple & Associates. The collection covers Wemple's entire career, however the bulk spans the 1970s to 1995, the year before the firm closed, representing approximately 2000 projects. The vastness and variety of the firm's commissions include those for large-scale civic centers, public parks, commercial buildings and shopping malls, and small-scale residential structures. Most of the archive consists of architectural drawings. There is also a substantial quantity of project files with various types of documents, slides of projects, articles about Wemple and horticultural research materials.

Series 1. Projects is the bulk of the collection, which is loosely organized alphabetically by project name and dated from the 1960s to 1996. Included are approximately 800 rolls of architectural drawings and plans, with about 20 or more in each roll, some of which are hand-drawn in pencil and/or color. Many different projects can be housed in a single roll. Approximately 170 rolls of drawings remain unlabeled and could include projects from the 1960s. They are segregated and will be closed to the public until identification can take place.

The related project files, most of which date from the early 1980s to 1996, include correspondence, engineering specifications, contracts, invoices, cost calculations, reports, proposals, and photographs. Material of this sort from the 1960s and 70s is generally not included and presumed lost. When applicable, project numbers are given next to project titles. The first two digits of a project number indicate the year the project began; the remaining digits represent a numeric order within a given year.

Series 2. Slides includes a large quantity of images of finished projects, generally arranged in alphabetical order in binders according to project type. Some of the images are of copies of drawings and plans, presumably made for presentation. There is also a box containing reference images of plants, and a very small quantity of miscellaneous photographic prints.

Series 3. Articles and Research contains articles about Wemple, including an entire box about the Getty, reports and plans by others, misc. publications, and magazines and books pertaining to plants.

Series 4. Miscellaneous includes ELWA resumes and articles of incorporation, various Wemple projects outside of ELWA, award certificates received for outstanding work in the field of landscape architecture, and personal letters received.