
| 1989 | Brooklyn Botanic Garden's Children's Garden |
| 1990 | Arboretum School of the Barnes Foundation |
| 1991 | University of British Columbia Botanical Garden, Plant Introduction Scheme |
| 1992 | The North Carolina State Arboretum, Plant Research, Evaluation and Introduction |
| 1993 | Minnesota Landscape Arboretum, Youth Education Program |
| 1994 | North Carolina Zoological Park, Sonoran Desert Collection |
| 1995 | Nebraska Statewide Arboretum, Community Landscape Improvement Program The National Tropical Botanical Garden, Growing Seed: The Wiliwili Project |
| 1996 | The Holden Arboretum, Conservation Program Santa Barbara Botanic Garden, Plant Scholars Program |
| 1997 | Harold L. Lyon Arboretum, Micropropagation of Endangered Hawaiian Plants |
| 1998 | Midwest Public Gardens Collaborative: Chicago Botanic Garden The Holden Arboretum Minnesota Landscape Arboretum Missouri Botanical Garden The Morton Arboretum |
| 1999 | Minnesota Landscape Arboretum's Andersen Horticultural Library |
| 2000 | EARTH University |
| 2001 | Dallas Arboretum & Botanical Garden |
| 2002 | Marie Selby Botanical Garden |
| 2003 | Brooklyn Botanic Garden |
| 2004 | Atlanta Botanical Garden North Carolina Botanical Garden |
| 2005 | New England Wildflower Society |
| 2006 | Albuquerque Biological Parks Rio Grande Botanical Garden |
| 2007 | Nebraska Statewide Arboretum |
