THE HEART OF THE MATTER

From a distance, the yellow floating heart might seem like the perfect ornamental plant for your pond. But just below the water’s surface, the lily grows thick roots, develops mattes dense enough to stop a boat’s propeller, and outcompetes native plants.

The yellow floating heart originated in Eastern Asia and the Mediterranean, according to

the U.S. Geological Survey. This lily is characterized by floating, heart-shaped leaves and bright yellow flowers.

Oklahoma State University originally became concerned with the yellow floating hearts

when they started growing in Lake Carl Blackwell, said Karen Hickman, OSU environmental

science program director.

“Lake Carl Blackwell is owned and managed by OSU,” Hickman said. “It provides the

drinking water for the university campus and recreation, so it’s a vitally important body of water for OSU.”

Graduate students in the environmental science program in the College of Agricultural

Sciences and Natural Resources were the first to conduct research on the plant.

“It was assessed about three to five years ago,” Hickman said. “They mapped [the plants]

and found [they were] increasing at a rate close to two acres a year.”

The plant, which had covered up to 60 acres of the lake’s 3,350 acre surface area, was

resistant to treatments of aquatic glyphosate, commonly known as Roundup, Hickman said.

“There were concerns about treating the aquatic plant with a chemical because it had the

potential to contaminate a body of water that could be drinking water,” Hickman said. “When the glyphosate wasn’t very effective, [OSU] had to find something else.”

Hickman decided to make the yellow floating heart issue a project option in her

environmental science capstone course. In the year-long course, students spend the fall semester researching their topics and the spring semester developing potential plans of action.

Four students were assigned to the yellow floating heart project: Heath McDonald, Dallas Ladd, Shannon Wilson and Luis Martinez.

“There’s not a lot of detailed information on how to control the yellow floating hearts, so

we had to reach out to a lot of industry professionals and get their ideas of what they’d do in this situation,” McDonald said. “We did a lot of reading on the OSU library databases.”

Lack of information was the group’s biggest challenge, McDonald said. They based their

idea on research of similar lily species.

Collaboration with groups across campus gave the student team the opportunity to

improve their communications skills, Wilson said.

“We had to learn how to talk to not only our peers,” Wilson said, “but also to doctorate

professors and really important people who had a lot of influence on the project. [They were]

people who had a lot of knowledge about [yellow floating hearts] and were a lot smarter than us. So, learning how to communicate was a big thing.”

The undergraduate student team worked with the graduate students to gather data, Wilson

said.

“They were the ones going out and collecting samples, taking pictures and gathering

data,” Wilson said. “So, we had to communicate with them to get the research from them.”

The plants in Lake Carl Blackwell were tracked through satellite and drone images to

determine surface area coverage, said Andrew Dzialowski, an associate professor of integrated biology and aquatic ecologist involved in the project.

Eventually, the students’ research led them to organizations in Wisconsin and

Washington that had successfully dealt with the yellow floating hearts, Hickman said.

“They were able to connect with a company that had a chemical approved for use —

ProcellaCor,” Hickman said.

ProcellaCor, a selective herbicide, “specifically targets a hormone mechanism that is

unique to plants,” according to SePro, producers of the chemical, which allows the user to kill

nuisance plants while protecting wanted plants.

According to SePro, the product has less risk than other products and less needs to be

used to control nuisance plants.

By the end of the capstone course, the students had written a comprehensive plan for

dealing with the plant.

“The students identified the treatment,” Hickman said. “They came up with the plan on

how and when to treat it, how much it would cost and compared it to other treatment options.

Then, [OSU] treated [the plants] this summer, using the students’ recommendations.”

Before application, the university took precautions to ensure the safety of the water and

natural ecosystems, Dzialowski said.

“Management at Lake Carl Blackwell worked with a certified applicator in the state,”

Dzialowski said. “The Oklahoma Department of Environmental Quality was involved. The

Oklahoma Department of Conservation was involved. The planning brought in people of

different expertise.”

One of the biggest precautions taken was temporarily changing the campus’ source of

water while treatments were applied to Lake Carl Blackwell, Dzialowski said.

“That wasn’t required by law, but [OSU] thought it was appropriate,” Dzialowski said.

“We did some detection and water-quality testing. We collected samples at the water intake, and we did not detect [ProcellaCor] in the water.”

After the ProcellaCor application, the team saw a significant reduction in yellow floating

hearts’ coverage, Dzialowski said.

“The last time I checked, [yellow floating heart] covered between two and three acres of

surface area,” Dzialowski said. “So, it worked really well.”

Despite the treatment’s success, OSU will continue to monitor plant regrowth to

determine next steps, Dzialowski said.

“The treatments were really successful, but it’s going to grow back in some places,”

Dzialowski said. “There will probably be some need for additional applications, but I think we’re all really surprised at the success.”