Kenneth D. Cochran
Current studies and diverse samplings of information concerning Ginkgo biloba are indicants that the marketing of this species has capacity for growth. Marketing will depend on production meeting demand. The adaptability and heritage of Ginkgo is highlighted, and the importance of asexual propagation from superior staminate trees is emphasized. Production and marketing of cultivars of Ginkgo should be based on selecting:
The East-West ties with Ginkgo biloba circle the globe. It probably originated in the temperate mixed mesophytic forests of Asia. The species was introduced into Europe through the Botanic Garden of Utrecht, Holland, in 1730, and then, in 1785 into North America from England to "Woodlands," the estate of William Hamilton (2).
In their search for tomorrow's plants, it is doubtful that early collectors knew the potential importance of this species to landscape horticulture. It is probable that their driving force was a passion for the species, whether for its legendary history, its charm, or its pattern of longevity. The Ginkgo has a noble heritage that has played a role in medicine, religion, and science.
Basic studies, observations, and current views are presented to indicate that the marketing potential for Ginkgo biloba in the United States and beyond has capacity for growth. This study is not comprehensive but rather a compilation of diverse samplings of information from horticulturists in California, Oregon, Ohio, New Jersey, and other states (3).
It has been closely associated with human beings for more than 5,000 years. Most Americans are familiar with Ginkgo either through childhood, school, or nature studies.
Yet seldom is it found growing in the residential landscape. Today, it is considered a tree for collectors. People are startled when they come across a Ginkgo and generally their first reaction is "Where do you get a ginkgo?" The acceptance of Ginkgo in the home landscape has developed slowly.
For more than 50 years, horticulturists in parks and public places, commercial landscapes, and street tree plantings have made use of Ginkgo (4). The species is particularly useful because of its resistance to insects and diseases (5). Therefore, it is appropriate for this species to be marketed as an environmentally friendly tree because pesticides are not needed in general tree management.
Trees in America have not always been recognized for their adaptive use, but rather have been selected for shade or aesthetic qualities. Adaptability of a tree means that it is tolerant of varied soils (modified soils other than shallow or poorly drained) and environmental conditions (temperature and precipitation). The trend toward recognizing the importance of adaptability started with the decline and death of various species of trees under stress. Ginkgo is considered one of the toughest and most adaptable of all cultivated trees in the temperate zone (4).
It is difficult to gauge the potential acceptance of Ginkgo in U.S. markets because nurseries have not produced enough trees of this species to test the market. Full recognition of this potential will only occur when nurseries produce and distribute enough trees so the public's reaction can be evaluated. Currently, wholesale nurseries report that demand exceeds supply (3).
The major opposition to Ginkgo is the abscission of the malodorous ripening fruit. The use of staminate cultivars from 50- to 60-year-old trees would overcome this objectionable characteristic. An enterprising municipal arborist in East Orange, New Jersey, had firemen use firehoses to knock the fruit from pollinated trees and then cleaned up the fruit before it fell under the onslaught of foot traffic (6).
A checklist of cultivated ginkoes lists 23 valid cultivar names (7). To that list the following cultivars are added: 'Magyar' (8), 'Firehouse' (9), 'Maytown' (10), 'Halka' (11), 'Tremonia' (12), and 'Horizontalis'(13). Today, the most frequently listed cultivars in U.S. nurseries are 'Princeton Sentry' PP#2720, 'Magyar,' and 'Autumn Gold.'
There is confusion about the verification of cultivar names. The cultivar 'Lakeview' originated at Lakeview Cemetery, Cleveland, Ohio. Nurseries asexually propagated from various ginkgoes at Lakeview and used the cultivar name 'Lakeview' for their progeny. Therefore, there are various clones of Ginkgo under the single cultivar name 'Lakeview.' This also happened during propagation of the cultivar 'Fairmount.'
It is interesting to note the origin of a few cultivar names. For example, the cultivar name 'Magyar' was selected in reference to a tree growing in front of the Magyar Bank in New Brunswick, New Jersey; 'Sinclair' was discovered in front of the Sinclair gas station in Princeton, New Jersey; and 'Princeton Sentry' was named for a tree selected from a row of ginkgos in a Prince-ton Cemetery (8). There are cultivars with non-valid names such as 'Cleveland,' 'Canopy,' and 'Umbraculifera' (7).
Many U.S. cultivars of Ginkgo have been selected and asexually propagated from superior staminate trees found in existing landscapes. Asexual propagation is the recommended technique to assure duplication of a parent plant.
Five to 15 centimeter caliper trees from asexually propagated cultivars of Ginkgo biloba have shown enough form variation in their branch structure that it is doubtful whether tree form can be predetermined in vegetative propagation. The following replicated cultivars were used in this study: 'Autumn Gold,' 'Princeton Sentry,' 'Sinclair,' and 'Lakeview.' Each cultivar replication showed variation in branch structure. In asexually propagated trees, one would expect similar branch structure within a cultivar.
The cultivar variation in Ginkgo may be answered by the work of Peter Del Tredici of the Arnold Arboretum of Harvard University. Dr. Del Tredici has demonstrated topophytic effect in Ginkgo biloba (14). His work indicates that vegetatively propagated lateral branches of ginkgoes will result in propagules that will continue in a lateral direction. It seems certain the cultivar 'Horizontalis' originated from a 90-degree angled branch of a Ginkgo biloba.
Ginkgo has varied branch orientation on a single tree. Scionwood collected from three branch structures will produce a comparable number of trees, each with a different formation.
William Flemer III of Princeton Nurseries, New Jersey, states that "it is hopeless to expect spreading forms of Ginkgo to be asexually reproduced and developed with a central leader and a whorl of spreading branches" (8). Scions selected from spreading trees for budding or grafting need to be staked to develop a central leader. Mr. Flemer's experience reveals that when the staked central leader grows beyond the stake, the leader grows horizontal. As a result of this experience, Princeton Nurseries will not grow cultivars that originate from a spreading clone. They grow 'Prince-ton Sentry' and 'Magyar' which have acute and rounded, angled branch formation. Princeton Nursery has grown quite a few spreading males, but none of these cultivars remain in production today.
Barrie D. Coate, former director of horticulture at Saratoga Horticultural Research Foundation, reports that they have made selections of Ginkgo cultivars from seedling trees growing along streets and backyards in California (15). One of the finest selections was chosen for autumn color. It was named cv. 'Autumn Gold.' The parent tree is not alive today, but it originated as a spreading form. Coate says that he found that asexually propagated trees of this cultivar are erratic in trunk and branch formation. He also noted that cv. 'Saratoga' originated from a symmetrical parent tree, but of all the progeny that he has seen, none are like the parent tree.
Keith Warren of J. Frank Schmidt and Son Co. in Oregon says, "We are new at the Ginkgo game," but the company has moved from the experimental to the production stage (16). He said he suspects that in propagating from lateral branches, the meristem will maintain lateral growth. However, Warren noted that he has not yet replicated enough trees for confirmation. He said he has seen trees of Ginkgo cultivars that fail to meet the horticulture forms under which they are registered.
A rather striking use of Ginkgo in the city landscape is evident at Cleveland's Gateway, Jacob's Field (Cleveland Indians Baseball Stadium), and Gund Arena in Ohio. Two hundred and sixty male cultivars of Ginkgo biloba are planted around the perimeter. Ginkgo was chosen by the site planners because of its autumn color; its more vertical than spreading habit, and the unifying element and scale that the species provides in this urban landscape. Darrell Bird, landscape architect, said, "I do not know what other tree we could have used on the Gateway project to get the effect we wanted" (19).
The production and marketing of Ginkgo in the United States and beyond is believed to have a definite capacity for growth.
Here's why: Ginkgo:
Marketing of Ginkgo directly depends on:
One might consider experimenting with a branch bending technique early on in production by hanging weights on young side branches, or inserting "spreaders" to develop a little more width to the overall tree. This technique has been used successfully in the orcharding of apple trees (17).
I am proposing an international exchange of Ginkgo scionwood based on the criteria outlined in this paper. From an experimental point of view, my initial desire is to contribute scionwood from an outstanding Ginkgo more than 75 years old (18).
Secrest Arboretum would welcome the exchange of an outstanding Ginkgo from Poland. Perhaps this exchange will result in a cooperative venture for marketing Ginkgo internationally. This is a small step for the Ginkgo, but could be a big step for nursery marketing internationally.
1. A meeting at the Ohio Agricultural Research and Development Center, Secrest Arboretum, Wooster, Ohio, July 1, 1997, which included Karol J. Piatkowski of Konin and Wojtek Grabczewski of Warszawa, Piotr Goraczko and Leszek Stanislaw and Ryszard Zwierowicz of Olsztyn.
2. This estate later became the Woodlands Cemetery of Philadelphia, Pennsylvania.
3. Discussions with horticulturists including nurserymen in California, Oregon, Illinois, Ohio, Michigan, Pennsylvania, and New Jersey.
4. "Ginkgo and People - A Thousand Years of Interaction," Peter Del Tedici, Arnoldia 51 (2) 2-15, 1991.
5. "The Ginkgo, The Most Ancient Living Tree," Randolph T. Major, Science 157: 1270-1273, 1967.
6. Reported by Harry J. Banker of West Orange, New Jersey.
7. "Checklist of Cultivated Ginkgo," Frank S. Santamour Jr., Shan-an He, and Alice Jacot McArdle, Journal of Arboriculture 9(3): March 1983
8. Conversation with William Flemer III and Louise Gross, Princeton Nurseries, Princeton, New Jersey.
9. Conversation with Robert K. Sieben-thaler, The Siebenthaler Company, Dayton, Ohio.
10. Conversation with Tom McCloud, Appalachian Nurseries, Inc., Waynesboro, Pennsylvania.
11. Conversation with Chet Halka, Halka Nurseries Inc., Englishtown, New Jersey.
12. A plant received at Secrest Arboretum from C. Klyn and Company, Boskoop, Holland, through Walter Sutcliff, Glen Head, New York.
13. Plant name verified by the Botanical Garden of Leiden, Leiden, Holland.
14. "Topophysis in Gymnosperms: An Architectual Approach to an Old Problem," Peter Del Tredici, Combined Proceedings, International Plant Propagators' Society, 41:406-409, 1991.
15. Conversation with Barrie Coate, Barrie D. Coate and Associates, consulting arborist, Los Gatos, California, and member, Board of Trustees, Saratoga Horticultural Research Foundation, San Martin, California.
16. Conversation with Keith Warren, Horticulturist, J. Frank Schmidt and Son Co., Boring, Oregon.
17. "Influence of Training Stakes and Various Pruning and Bending Techniques on Early Performance of 'Fugi' Apple Trees," D. C. Ferree and J. C. Schmid, Ohio Agricultural Research and Development Center, Research Circular 298, pp. 11-17, June 1994.
18. Located in Wooster, Ohio, USDA Hardiness Zone 5b, originated from a seedling sent to the United States from Japan; currently 37 inches DBH and 65 feet in height (measured by Jim Karcher, Wooster, Ohio).
19. Conversation with Darrell R. Bird of Sasaki Associates Inc., Watertown, Massachusetts.