News and Stories

Kentucky Clover is being grown, harvested, reintroduced, and frozen

CINCINNATI, OH (September 3, 2024) – Scientists and horticulture experts at the Cincinnati Zoo & Botanical Garden are working with the Office of Kentucky Nature Preserves (OKNR) with funding from the U.S. Fish & Wildlife Service to help restore populations of the endangered Kentucky Clover (Trifolium kentuckiense) that was once known to occur in two populations in the state but disappeared in more recent surveys.

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“Kentucky Clover is a newly discovered species and, because of its rarity, OKNR developed a plan for restoring populations of this plant,” said Dr. Valerie Pence, director of plant research at Cincinnati Zoo’s Center for Conservation and Research of Endangered Wildlife (CREW). “CREW was asked to propagate plants for these restoration projects and to produce seed for banking both at CREW and at other seed banks around the country.”

“CREW and the Zoo’s horticulture team have been instrumental in preventing the extinction of this globally rare clover.  With the plants they have grown, we have established populations of Kentucky clover on four protected sites in the bluegrass and continue to monitor survival rates and seedling establishment.  We are happy to report up to 60% survival rates in these newly established populations and are excited to continue to work with CREW on building up the seedbank to ensure long term success” Tara Littlefield, botanist and biological assessment branch manager at the Office of Kentucky Nature Preserves.

CREW is working on creating and maintaining a tissue culture collection, providing an ongoing source of plants. Shoots of the plant are propagated in test tubes on sterile medium.  These shoots can be rooted by changing the medium, and once they’re rooted, they can be removed from the tubes and acclimatized to soil.   Once they are able to handle being outside of a test tube, they are taken to Bowyer Farm where the Zoo’s horticulture team continues to grow them and establish them into larger pots.

“After we receive the plants from CREW, we let them fill out the pots that they came in, label them, and track each individual plants so we know exactly where the genetics are coming from,” said Brian Jorg, a horticulture manager at the Cincinnati Zoo & Botanical Garden. “Given time, water, and fertilizer, they fill into very nice plants.”

“The goals are to deliver 1500 propagated plants to Kentucky Nature Preserves over two years, to use for restoration, as well as at least 2500 seeds for direct seeding at the restoration sites.,” said Mairead Kennedy, plant lab manager/conservation horticulturalist at CREW. “We also are contracted to provide at least 5000 seeds for seed banking. This plant seems to be able to produce a large amount of seed under the conditions at Bowyer Farm, so we think we’ll be able to provide a substantial amount for banking as insurance, to keep this plant safe for the future.”

The Kentucky Clover Project, CREW, and the Zoo’s horticulture team are thrilled to be a part of this conservation effort and are getting closer to honing in on the methods that are necessary to store these long term and further conserve this species.

For more information on the Kentucky Clover Project and its conservation efforts, visit the Kentucky Native Plant Society¹.

If you’re interested in learning more about the work that Cincinnati Zoo & Botanical Garden is doing at Bowyer Farm, visit Cincinnatzoo.org or register (free) to attend upcoming

Native Plant Sales at Bowyer and see for yourself.  There are two sales in September and two in October.

Visit Cincinnati Zoo & Botanical Garden during regular zoo hours – 10 a.m. to 5 p.m. daily.  Members get Early Entry and are welcome to enter the Zoo at 9 a.m.

DID YOU KNOW…. You pay more than $10 less per ticket, on select days, when you purchase tickets online!  That’s a $40 savings for a family of 4!