2023     Pitzer College
2022     Los Angeles Pierce College - Fernando Garcia-Ibarra
             Los Angeles County Arboretum and Botanical Gardens
2021     Rancho Los Alamitos - Matthew Castner
             Mt. San Antonio College - Marisa Virgen
             The Huntington Library, Art Museum, and Botanical Gardens - Bridget Lee
2020     Theodore Payne Foundation - Sharon Zarate
2018     California State University, Northridge
             Rancho Santa Ana Botanic Garden
2017     Rancho Los Alamitos (deferred to 2021)
2016     LA County Museum of Natural History
             Virginia Robinson Gardens
2015     Rancho Los Cerritos
2014     Descanso Gardens
2013     Los Angeles Co. Arboretum
2012     The Huntington
2011     Theodore Payne Foundation
             South Coast Botanic Garden
2010     Rancho Los Cerritos
             Cal State University, Northridge
2009     Rancho Santa Ana Botanic Gardens
             Rancho Los Alamitos
             Pitzer College
2008     Virginia Robinson Gardens
2007     Descanso Gardens
             Los Angeles Co. Arboretum
2006     The Huntington
             Theodore Payne Foundation
2005     South Coast Botanic Garden
             Cal State University, Northridge
2004     Rancho Santa Ana Botanic Gardens
             Rancho Los Alamitos
2003     Mildred Mathias Garden, UCLA
             Virginia Robinson Gardens
2002     Descanso Gardens
             Los Angeles Co. Arboretum
2001     The Huntington
             Theodore Payne Foundation
2000     Mildred Mathias Garden, UCLA
             Los Angeles Co. Arboretum
1998     Theodore Payne Foundation
1997     Los Angeles Co. Arboretum
1996     Rancho Santa Ana Botanic Gardens
             Descanso Gardens
1995     Descanso Gardens
1994     Virginia Robinson Gardens
             Rancho Santa Ana Botanic Gardens
1993     The Huntington
             Descanso Gardens
1992     Los Angeles Co. Arboretum
             The Huntington
1991     Los Angeles Co. Arboretum