Red Hill at Archbold Biological Station, a remnant sandhill once slated to be the Roebling estate, is now the home of the Florida Ziziphus (also called Florida Jujube), one of the rarest plants in the state. Archbold researchers planted 73 Florida Ziziphus plants, a thorny shrub with glossy leaves, in August 2023 as part of an ongoing effort funded by the Florida Endangered and Threatened Plant Conservation Program to rescue the species from the brink of extinction.

Florida Ziziphus is narrowly restricted to the Lake Wales Ridge and known from just 13 wild populations in Highlands and Polk Counties. The species is so rare, in fact, that it was missed by many of the most prominent Florida botanists of the 20th century, and only described by science in 1984, at which time it was thought to be long-since extinct. Since then, expert botanists and amateurs alike have kept their eyes peeled for this enigmatic shrub, and its re-discovery likely saved it from the extinction, which was prematurely ascribed to it.

So how did Florida Ziziphus end up at Archbold? In the last 25 years, Archbold researchers have performed numerous introductions, that is, planting an endangered species on protected land in appropriate habitat where it was not present before, to essentially serve as a ‘back-up’ if wild populations don’t make it – indeed, most wild Florida Ziziphus are located on private land with no conservation protection. Researchers have introduced Florida Ziziphus to several state, federal, and non-profit protected lands throughout the Lake Wales Ridge. In addition, Florida Ziziphus was once thought to be restricted to the northern part of Highlands County, but the most recent wild Florida Ziziphus discovery in 2017 was made in Lake Placid, near the shores of Lake Apthorpe. This 12-mile range-extension opened up the possibility of new introductions in this area of the county, which included Archbold.

<Caption: Archbold and Bok Tower Gardens staff (Top L-R: Cheryl Peterson, Jeffrey Dosdall, Sterling Heron, and Chico Rivera; Bottom L-R: Aaron David, Hannah Bowen, and Vaughn-Jordan research intern Eric Liu) at the new Florida Ziziphus introduction site. Photo by George McKenzie, Jr.

Photo by: George McKenzie, Jr.

Caption: Archbold staff (Aaron David, Jeffrey Dosdall, Sterling Herron, and Vaughn-Jordan research intern Eric Liu) carrying Florida Ziziphus plants to the new introduction site. Photo by George McKenzie, Jr.

A great deal went into the successful establishment of the new Archbold introduction. Close collaborators of Archbold at Bok Tower Gardens (Lake Wales, FL) germinated Florida Ziziphus seeds from the annual fruit harvest of Florida Ziziphus located in the National Collections of the Center for Plant Conservation. Cheryl Peterson of Bok Tower Gardens has led these efforts and learned a great deal about the germination requirements of Florida Ziziphus and how to grow the plant in a horticultural setting. At the introduction site, irrigation lines deliver water to each individual plant on a regular basis. Irrigation is critical at this early stage, as drought during the early establishment of transplants is known to be a major cause of mortality.

This new Florida Ziziphus introduction represents a new sanctuary for the species and will also serve as a research opportunity. Much remains to be learned about Florida Ziziphus genetics, its reproduction, and how fire impacts it. Having Florida Ziziphus in Archbold’s “backyard” will allow future researchers and visitors ready access to this otherwise elusive plant.

Dr. Sterling Herron, the Archbold Plant Ecology Research Assistant who leads the project, summarizes, “The problem of saving the Florida Ziziphus remains a prickly one, with obstacles including very limited genetic diversity, lack of fruiting, and diminishing sandhill habitat, being a few. While setting up new introductions is pivotal to the long-term success of Florida Ziziphus, they appear to take decades to become established and form a full-fledged, self-sustaining population. Some may even compare the challenge of rescuing Florida Ziziphus to the toils of Sisyphus! Nevertheless, the careful establishment of these introductions now is an investment in the future conservation of this species, one we believe to be very much worthwhile. Species like Florida Ziziphus, occurring here and nowhere else on Earth are some of the most quintessential emblems of wild Florida, and we want to see them preserved for future generations to enjoy.”