THE ISSUE: Yellow floating heart

Yellow floating heart (Nymphoides peltata) is an aquatic perennial weed, native to the Mediterranean and Eurasia. Its presence negatively impacts biological diversity, native plants, native ecology, and wildlife habitat.  

Yellow floating heart gets its name from large heart shaped leaves that float on the top of the water. The leaves are green to yellow green in color. Leaves are shiny and 2-6 inches across. Bright yellow flowers are formed in clusters of 2-5 flowers per cluster. Flowers have 5 fringed petals and are housed on stems about 3 inches above the water. Yellow floating heart is a dangerous weed because it spreads very easily. It can spread by seed (transported great distances by waterfowl), by rhizomes (runners under the water surface) and by broken plant parts that float to new areas. Unfortunately, this weed is a popular water garden plant and can still be purchased in some regions.

Integrated Pest Management (IPM) Options: 

• Prevention— Learn to identify this plant. Never dispose of aquarium contents in bodies of water. Always clean, drain, and dry watercraft before transporting to new locations. Report sightings to local authorities.

• Mechanical— Hand digging or pulling can be effective on small infestations, extreme care should be taken to remove as much of the plant as possible. This plant can spread by broken plant parts.

• Cultural— Control measures should be taken before flowering occurs. Waterfowl that consume seeds can transport them to new areas.

• Chemical—Unfortunately, this weed can be very difficult to control using chemicals. It has a thick waxy layer on its leaves that prevents chemicals from penetrating. Contact local authorities for chemical control options. Always read and follow herbicide label directions!

Justin Hatch, University of Idaho Extension Agriculture Educator in Caribou and Bear Lake County. 208-547-3205
[email protected]