News and Stories

Happy National Roots Day! The scientists in the Plant Division at the Center for Conservation and Research of Endangered Wildlife (CREW) want to celebrate both our plant roots and our history! For over three decades, CREW’s Plant Division has developed propagation protocols for dozens of threatened species using plant tissue culture. One step in that protocol is producing healthy roots, so that the plant can be moved to soil and eventually back to the wild. For some species, rooting occurs readily, while others require further research to determine the conditions that will coax that species to produce roots. It took two years of testing to find a medium on which the four-petal pawpaw, Asimina tetramera, a threatened species found only in Florida, would produce roots. That same procedure has since been used for rooting other threatened Florida pawpaws, including Beautiful pawpaw (Deeringothamnus pulchellus) and Rugel’s pawpaw (Deeringothamnus rugelii), producing plants that have been used to help restore those species in the wild.

Once the plants growing in tissue culture have developed strong roots, the next step in the protocol is to acclimatize them to soil. Acclimatization is a step-down process that prepares plants to transition from growing inside a test tube to growing outdoors. Scientists at CREW work with a large variety of species, all of which have different light, humidity, and watering requirements. To best accommodate each plant, researchers conduct experiments to find the optimal growing conditions for each species. Some species are easier to acclimatize than others, but finding the ideal methodologies for acclimatization of our endangered species at CREW allows us to provide healthy plants for in-situ conservation efforts.

While some species, like Asimina tetramera, require extensive research to produce roots in tissue culture, others develop strong roots rapidly. Despite being critically imperiled, the Kentucky clover (Trifolium kentuckiense) is one of the fastest rooting plants in tissue culture at CREW. A new propagule will start putting out roots in just a couple days, and in 2 weeks, many of the plants will be ready to be acclimatized and moved outdoors. In 2025, scientists at CREW mass-propagated the Kentucky clover for restoration in their native habitat. Plants were propagated onto rooting media in February 2025, acclimatized in CREW’s greenhouse, then sent to Bowyer Farm, where they were repotted and cared for until the outplanting in April 2025. In just two months, CREW produced almost 1,000 Kentucky Clover plants that were strong enough to survive an outplanting in the wild. At CREW, we are always “rooting” for a brighter and greener future!