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Developers Say People, Glade Cress Can Coexist In Louisville; Experts Doubt It

The largest remaining habitat for Kentucky glade cress will be developed into a subdivision whose profits will support the Parklands of Floyds Fork — a nearly 4,000-acre park next door.

The decision comes after the Louisville Metro Planning Commission approved plans in July to build on the existing subdivision, adding as many as 592 single-family lots and up to 350 apartments.

Developer 21st Century Parks Endowment says current plans will directly impact less than two percent of the on-site population of glade cress — a plant that grows nowhere else in the world. The developer has pledged to adjust and remove lots where glade cress occurs and create open spaces to protect the plants.

But that will still leave some of the nearly 800 identified plants close to, and at times surrounded by, streets and single-family homes.


When the U.S. listed the plant as “threatened” under the Endangered Species Act, it noted development as the most significant threat facing glade cress.

There are only about 50 distinct glade cress populations in the world — and all of them are in Jefferson and Bullitt counties. Glade cress grows in shallow soils atop rocky dolomite outcrops — two to four inches high — producing miniature white and lilac blossoms.

The delicate, annual plants will face the same threats that accompany any new development including erosion, shading, invasive species and suburban runoff, which can carry herbicides and pesticides.

That’s why conservationists, professors and scientists say it’s critically important the endowment take precautions to ensure known glade cress populations can survive long-term.

It only takes one bad season to kill the plant and prevent its seeds from spreading, said Jeff Frank, Friends of Floyd Fork founder.

“It’s an annual so it just takes one event of herbicide or pesticide or somebody being careless and taking the plants out before they’ve had a chance this year to bloom and set seed,” Frank said.

Plans To Protect Glade Cress

21st Century Parks Endowment acquired the Oakland Hills subdivision after sales slumped during the Great Recession, said Joe Daley, architect and project manager.

“We thought about it long and hard and about the third time we were asked, the endowment decided to purchase the land and saw it as an opportunity to raise some funds to support the park next door,” he said.

The endowment surveyed the property this spring using consultants that included U.S. Fish and Wildlife, Daley said. They identified 786 plants in 27 patches spread among the 462-acre property, he said.

Legally, the endowment isn’t required to protect the glade cress, though it intends to, said Daley.

“The glade cress issue really isn’t a requirement on private development, it’s required when you have a federal permit,” Daley said. “But we obviously have been concerned about it.”

The endowment is now working on designs to protect the glade cress, Daley said. They have not offered specifics, but say plans will include buffer zones that could be 100 feet.

Daley said runoff is unlikely to be an issue because of the topography where plants usually grow, but Frank, with Friends of Floyd Fork, said many of the glade cress populations he’s identified are perched at the edge of ridge tops below land where developers plan to build.

Giving Glade Cress A Fighting Chance

Cutting glade cress off from its habitat and surrounding it with suburban and urban development would be a recipe for a slow death, according to a group of five scientists, professors and conservationists who spoke to WFPL News.

“A glade cress population that is surrounded by residential homes and apartments, it’s unlikely that glade cress will be able to persist there,” said Deborah White, a botanist and one of the state’s foremost experts on glade cress.

She also said a 100-foot buffer is not enough to protect the glade habitat from weeds, invasive plants and disturbance from neighbors.

White and other experts who spoke with WFPL News said the endowment has so far taken positive steps to protect the glade cress population, but added it’s difficult to know the future impact development will have without seeing plans.

Chair of the Kentucky Land Trust Coalition Don Dott said he would like to see future plans include long-term maintenance and nature corridors between patches of glade cress.

“Despite being a small plant, it does travel across the landscape to some extent and cross pollinate with the other flowers because it is an annual,” he said. “So if it gets surrounded, even if you protect it to the best of your ability, it’s probably going to eventually do it in.”

Ryan Van Velzer is WFPL's Energy and Environment Reporter. Email Ryan at rvanvelzer@lpm.org.

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