Fact Sheet

Fact Sheet: Yellow Floating Heart treatment planned at Lake Carl Blackwell


An invasive water lily called Yellow Floating Heart continues to spread at Lake Carl Blackwell. It is a non-native plant that could change the ecosystem and spread to other lakes. ProcellaCOR SC — an aquatic, species-specific herbicide — has been selected to control this invasive lily. ProcellaCOR SC is approved by the Environmental Protection Agency for use in drinking water. It is considered a reduced-risk herbicide that has no restrictions against recreation, including fishing and swimming, or drinking treated water.


Yellow Floating Heart is a native of Eurasia and the Mediterranean used as an ornamental and popular for outdoor water gardens. The plant (or plant fragments) can be transplanted to other areas during flooding or intentionally discarded into other large bodies of water. Waterfowl and other animals can also carry seeds to other bodies of water.

Damage Potential

Unchecked, this lily has the potential to continue to spread in water to a depth of 9-12 feet, according to OSU integrated biologist Dr. Andy Dzialowski, who has been tracking its growth. Today, the acreage of Lake Carl Blackwell affected is approaching 50. If untreated, over time, it may affect water quality, overtake native plant species, and reduce the recreational potential of the lake. If not controlled, Yellow Floating Heart is likely to spread from Lake Carl Blackwell to other water bodies. Yellow Floating Heart is prohibited in several states including Michigan, Minnesota, Wisconsin and others. It does not affect drinking water.

Proposed Treatment

ProcellaCOR SC is an aquatic, species-selective herbicide designed by SePro and has gone through eight years of laboratory testing. It uses a plant hormone-disrupting compound specific to broad-leaf plants. The EPA has labeled it with the lowest risk category possible — so low, in fact, that there is no requirement for water monitoring. ProCellaCOR SC is distributed 2 feet under the surface of the water from an airboat, where it will be absorbed through the roots of the plants. Only problem areas will be spot treated, not the entire lake. Less than 1% of the lake will be treated in all.

Treatment Date

Barring unforeseen issues with the weather, the application should start on July 9 and may take up to three days to complete. Additional treatments may be necessary. It may take up to seven weeks for the plants to die.

Public Safety Precautions

OSU will act with an abundance of caution. Before the ProcellaCOR application, university drinking water will be sourced from the city of Stillwater. Also, the water will be monitored at the intake near the dam every day that ProcellaCor is applied, plus daily tests for three days after the last application. The water will be tested weekly from the intake at OSU’s water treatment plant. The OSU Water Treatment Plant will not be in use until after tests show no measurable trace of the chemical.