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Home / Robert J. Armstrong Collection on New Guinea Impatiens

Robert J. Armstrong Collection on New Guinea Impatiens

New Guinea Impatiens hybrid cv. Juggler, introduced by Longwood Gardens’ plant geneticist Robert J. Armstrong in February 1977


On December 7, 1990, Dr. Robert J. Armstrong donated to the National Agricultural Library materials related to his role in breeding Impatiens species collected from New Guinea in 1970. The eleventh, plant exploration trip co-sponsored by USDA and Longwood Gardens resulted in the collection of over 800 ornamental plants, the most popular of which became the New Guinea impatiens. Both organizations studied these plants over several years and shared hybrid cuttings with commercial growers and the public.

The collection is 2 linear feet and fills 3 archival manuscript boxes. Dates of the material range from to 1971-1990. Materials include a pedigree book from the Longwood Gardens Breeding Program; slides showing the original New Guinea impatiens and the progeny developed from them at Longwood; and letters, memoranda, reports, and press releases concerning the breeding program. Katherine St. John arranged, inventoried, and described the materials in 1996. Sara Lee completed arranging and describing the collection in 2018.

Historical Sketch

Date Event
1886 New Guinea impatiens first introduced in Europe
Early 1900s Begonia mite infestations on plants caused limited cultivation
1956 Agreement made between Longwood Gardens (Longwood), Kennett Square, Pennsylvania and the U.S. Department of Agriculture (USDA), Agricultural Research Service, Horticulture Crops Research Branch, Beltsville, Maryland to co-sponsor plant exploration trips
January 4 – April 14, 1970 USDA plant explorers Harold F. Winters and Dr. Joseph J. Higgins embarked on a 10-week joint plant exploration trip to New Guinea to collect ornamental plants, resulting in 840 live collections of seeds, plants and cuttings
1971 USDA Germplasm Laboratory, Beltsville, Maryland provided Longwood with propagated plants from the plant exploration trip after a period of quarantine and inspection at the USDA Plant Introduction Station at Glenn Dale, Maryland

Longwood's geneticist Dr. Robert Armstrong selected New Guinea Impatiens for breeding because of their short life cycle
February 1972 USDA released and distributed the original collection of twenty-three New Guinea impatiens plants to public and private institutions; over one hundred universities and commercial plant breeders received them
1972 Mikkelsens Inc. in Ashtabula, Ohio released progeny of the original collection for sale to the public

Dr. H. Marc Cathey, Chief of Florist and Nursery Crops at USDA assigned research geneticist Dr. Toru Arisumi to study breeding behavior, genetics, and chromosome numbers and characteristics of New Guinea impatiens
April 1973 Winters, Head of the USDA Germplasm Laboratory, studied differences in flower longevity in plants grown in the greenhouses
1974 First set of ten, unpatented Longwood cultivars named the Circus Series released to selected gardens and growers

First USDA cultivars released under the Rainbow Series and made available to anyone who requested them
1975 USDA introduced two more cultivars to the Rainbow series
1976 USDA introduced a seed variety ‘Sweet Sue’
1977 Dr. Armstrong developed ten more Circus Series cultivars and released them to Longwood cooperators

USDA introduced the Painted Impatiens Series

Winters’ study published
1978 Longwood’s breeding program ended

At least sixty New Guinea Impatiens cultivars from various breeders were released by this point; popularity as a bedding plant
1979 Longwood made a final release of six Circus Series cultivars
1980 The cooperation of Longwood, USDA, other not-for-profit organizations, and commercial growers contributed to bringing the plant out of obscurity and making it the best-selling bedding plant in the United States in 1980 (Voigt 1989)
1986 Dr. Arisumi retired and the USDA New Guinea impatiens program was phased out; some of his plants were propagated and grown at the University of Maryland for electrophoretic research conducted by Ph.D. candidate Virginia Lerch

Scope and Content Note

The collection consists of 2 linear feet of materials gathered by Dr. Robert J. Armstrong in the course of research, development, and distribution of hybrids of New Guinea impatiens at Longwood Gardens. He recognized the importance of documenting the history of the breeding program and Longwood’s partnership with the U.S. Department of Agriculture. He provided to the National Agricultural Library his materials from Longwood, including a pedigree book he maintained for the breeding program, letters, notes, and slides of his work. Additionally, he contacted other participants involved in researching and distributing New Guinea impatiens to ask for their notes, reports, brochures, correspondence, and photographs for the collection.

In conducting research of New Guinea impatiens at Longwood, Armstrong used a shotgun approach to breeding. He bred each plant in every combination possible, resulting in over 1,200 color slides of plants grown in plots outside and in the conservancies. The slides are numbered and correspond to numerical entries in the breeding book. To locate the pedigree of an impatiens plant shown in a slide, one would note the identification number on the upper left-hand portion of the slide, then refer to the pedigree book and find the corresponding identification number.

Because of the showy look of the flowers and variegated foliage, Armstrong gave the first set of ten plants circus-related names. The Circus Series was released to selected gardens and growers in 1974, followed by ten more in 1977, and finally a set of six in 1979. The collection contains brochures of the hybrids released in 1977 and 1979. See the appendix for a list of all releases made by various breeders during this time period.

Armstrong received numerous letters from plant breeders, public horticulture institutions, commercial growers, and private plant collectors about Longwood’s research program, requests for cuttings of hybrids, and responses about the performance of the cuttings. Longwood staff distributed excess plants to their cooperators with the agreement that the cooperators would provide spare plants of interest to them. Correspondence between Armstrong and USDA plant explorer Harold F. Winters provides particular insight into the New Guinea impatiens breeding program.

Publicity materials in the collection consist of advertisements, USDA release notices, and distribution lists. Both Longwood and USDA developed commercial plant source lists to send in response to general requests for the plants as their purpose was developing the plant for display uses and distributing information about breeding and culture. At least one commercial grower, Mikkelsens Inc. in Ashtabula, Ohio, released progeny of the original plant exploration trip for sale to the public.

Other items of note include and a bibliography of articles written on New Guinea Impatiens and a copy of Joan Marie Benjamin’s comprehensive history of the development of New Guinea Impatiens in which she interviewed the key players involved in the partnership. Benjamin wrote this master’s thesis as a student of the University of Delaware’s Longwood Graduate Program, which was developed to train future leaders in the field of public horticulture.

Container List

Robert J. Armstrong Collection on New Guinea Impatiens. 3 boxes.
Box Folder Title/Description Date(s)
001 1 Donation letters from Robert J. Armstrong 1990
001 2 Thesis: The History and Development of New Guinea Impatiens by Joan Marie Benjamin for University of Delaware 1990
001 3 New Guinea impatiens bibliography 1978
001 4 Outline of seminar on the domestication of New Guinea impatiens 1985
001 5 Pedigree book for the New Guinea Impatiens Breeding Program at Longwood Gardens, Kennett Square, PA 1971-1978. 1984
001 6 Impatiens received from the USDA 1971
001 7 Impatiens color listings 1972
001 8 USDA distributed notice to plant breeders and nurserymen relative to the release of 23 Impatiens introductions 1972
001 9 USDA produced list of nurserymen who received propagation material of the New Guinea Impatiens collections 1972
001 10 Impatiens short day and temperature study 1973
001 11 Longwood-named hybrid impatiens 1973, 1976, 1979
001 12 Form letter from Armstrong to special distributors  
001 13 Notice of naming and release of 10 new hybrids of Longwood New Guinea Impatiens hybrids 1974
001 14 New Guinea Impatiens distribution lists 1974, 1977, n.d.
001 15 Special distribution order form for the Longwood New Guinea impatiens hybrids 1974, 1977, 1979
001 16 Letters and shipping receipts for plants sold to Longwood Gardens 1974-1979
001 17 New Guinea impatiens hybrid cultivar names used as of December 1975 1975
002 18 USDA distributed notice to cooperators among florists and nurserymen of the release of three new seedling cultivars of the painted impatiens series 1977
002 19 New Guinea impatiens hybrid brochures from Longwood Gardens 1977
002 20 New Guinea impatiens hybrid brochures from Longwood Gardens 1979
002 21 Brochure and catalog for New Guinea impatiens hybrids from other breeders 1979, n.d.
002 22 Source list for the Longwood New Guinea impatiens hybrids n.d.
002 23 Longwood New Guinea impatiens cultivars likely to be available commercially n.d.
002 24 Correspondence – Outgoing - Robert J. Armstrong 1971-1974
002 25 Correspondence – Outgoing - Robert J. Armstrong 1975-1980
002 26 Thank you notes to Robert J. Armstrong 1971-1983
002 27 Correspondence – Russell J. Seibert, Director, Longwood Gardens 1972-1975
002 28 Correspondence regarding requests for cuttings and distributor addresses 1972-1982
002 29 Correspondence. Miscellaneous. 1973-1984
003   New Guinea Impatiens slides  

Selected Bibliography

Sources Used for Finding Aid

Arisumi, Toru and H. M. Cathey. "About Our Cover, the New Guinea Impatiens." HortScience 11, no. 1 (February 1976): 2.

Armstrong, Robert J. "An Impatiens Circus, the Longwood New Guinea Hybrid Impatiens." American Horticulturist 53, no. 1 (Spring 1974): 14-18.

Benjamin, Joan Marie. The History and Development of New Guinea Impatiens. Thesis, University of Delaware, August 1990.

Creech, John L. "The ARS--Longwood Plant Explorations." Plants & Gardens 23, no. 3 (1968): 50-55, 86.

Winters, Harold. "New Impatiens from New Guinea." American Horticulturist 52, no. 3 (Fall 1973): 16-22.

_____. "Flower Longevity in New Guinea Impatiens." HortScience 12, no. 3 (June 1977): 261-263.

Related Collections at the National Agricultural Library

Harold F Winters Oral History, National Agricultural Library. To be released in 2019.

Related Collections at Other Institutions

The University of Delaware’s Longwood Graduate Program is a partnership that aims to train future leaders in the field of public horticulture. Below are theses related to the partnership of USDA and Longwood Gardens:

Benjamin, Joan Marie. The History and Development of New Guinea Impatiens. Thesis, University of Delaware, August 1990.

Tschanz, Eric Nathan. "A History: The U.S.D.A.--Longwood Ornamental Plant Exploration Program." Thesis, University of Delaware, 1977.

Longwood Gardens ARC - Archives. “Joseph Higgins papers on New Guinea Impatiens 1963-2004.” Accessed December 12, 2018.