For a quarter century the Chicago Botanic Garden has sent plant experts to the far corners of the globe on exploration trips. Garden scientists have studied and collected plants within the United States and on 27 trips into 20 countries, including China, Korea, Russia, and other exotic locations. These expeditions have targeted regions with climates and ecosystems similar to that of the midwestern United States to best ensure the plants brought back will succeed under our challenging growing conditions.
Collecting sites are carefully selected, based on a scientific review of environmental factors that can influence the success or failure of plants from other regions and countries here at the Garden. In this quest to identify the best sites, Garden staff analyze a number of factors, including the following:
- Precipitation patterns (annual quantity and seasonality)
- Temperature patterns (seasonal averages, highs and lows)
- Ecosystem similarity (deciduous forests, grasslands, etc.)
- Diversity of flora
- Soil pH and composition
- Length of growing season
Plant exploration trips help the Chicago Botanic Garden diversify its collections. They provide germplasm of documented wild-origin, newer forms of plants currently in cultivation (perhaps with different flower colors), improved disease resistance or drought tolerance — in fact, these expeditions have provided plants new to cultivation, such as Trillium camschatcense, Brachybotrys paridiformis, and Kalimeris lautureana. These plants are used for education, conservation, research, and display. The trips also facilitate collaborative relationships with like-minded institutions around the world, which can improve scientific study and increase awareness of and understanding about plants and their communities.
While discovering plants of horticultural merit is primary, Garden expeditions also provide plants of other interest, such as medicinal plants for study by ethnobotanists; rare and endangered plants studied for conservation purposes; and food plants, such as wild apples and English walnuts. Sometimes a plant's usefulness isn't apparent until years after it has arrived at the Garden; a timely example is four foreign-collected ash species that may prove resistant to the emerald ash borer. This exotic insect pest has destroyed more than 30 million native North American ash trees since first being observed in 2002. No North American native ash seems resistant, but these foreign ash species hold promise and may provide clues to developing resistance to this devastating insect. In time the foreign ash trees or their progeny may substitute for the susceptible native ashes in our urban landscapes.
The Garden is a founding member of the Plant Collecting Collaborative (PCC). Formed in 1992 to fulfill common institutional goals, the Collaborative is a consortium of six major public gardens and arboreta:
Chicago Botanic Garden, Glencoe, Illinois
The Holden Arboretum, Kirtland, Ohio
Missouri Botanical Garden, St. Louis, Missouri
New York Botanical Garden, Bronx, New York
The Morton Arboretum, Lisle, Illinois
University of Minnesota Landscape Arboretum, Chanhassen, Minnesota
As a whole, the Collaborative combines staff expertise in conservation, plant identification, propagation, horticulture, and scientific research. This combined expertise ensures that plant exploration trips are conducted in a thorough and scientific manner, and that the germplasm brought back is adequately protected, displayed, and studied.
Sharing plants as broadly as possible is perhaps the best way of preserving them for future availability and use. Seeds and plants obtained on Collaborative expeditions are always collected on a sustained-yield basis, ensuring the longevity of naturally occurring populations. The strict importation guidelines of the United States Department of Agriculture (USDA) and regulations of the host countries are always followed. This valuable plant germplasm is then shared within the cooperative, and often with other botanic gardens and arboreta, along with the USDA's germplasm repository.
Following each expedition, Chicago Botanic Garden scientists evaluate plants new to the country for their potential to naturalize and/or become invasive; their adaptability to this area's growing conditions; and their ornamental qualities. Plants deemed ornamental will be incorporated into the permanent Display Collections. Plants with superior or unique ornamental attributes are utilized by the Garden's plant breeding program or commercially introduced through the Chicagoland Grows™ plant introduction program.
The Garden's plant exploration program provides critical information in the worldwide effort to protect and preserve plants, while benefiting from their remarkable and diverse qualities.