VEGETATIVE PROPAGATION AND EX SITU CONSERVATION OF CHAPMAN’S RHODODENDRON IN ATLANTA BOTANICAL GARDEN

Abstract

Rhododendron chapmanii is a federally endangered, Florida-endemic shrub with a highly restricted and fragmented distribution. Updated field surveys reveal steep population declines across its range due to habitat loss, fire suppression, hurricane damage and over-collection. In response, the Atlanta Botanical Garden (ABG) has implemented an integrated conservation strategy that combines in situ monitoring, demographic research, and comprehensive ex situ safeguarding. Conventional hardwood and semi-hardwood cuttings achieved 70–80% rooting success by ABG’s conservation horticulture team. A new, efficient micropropagation protocol was developed using Anderson’s Rhododendron medium supplemented with zeatin and indole-3-butyric acid, enabling rapid, genetically stable shoot proliferation and high rooting rates. These propagation techniques support the efforts to expand the species’ safeguarded genetic base, reduce pressure on wild populations, and provide high-quality plant material for planned reintroductions guided by species-distribution modeling. This integrated approach positions ABG as a key leader in the recovery of R. chapmanii, demonstrating the critical role of coordinated propagation, genetic safeguarding and habitat management in preventing extinction of narrowly endemic plants.