Crested floating heart
The numerous small heart-shaped leaves of Nymphoides cristata float on the water surface while roots grow into the hydrosoil. Five-petaled white flowers rise on small stalks above the leaves. A white ruffle lining the middle of each petal distinguishes the plant from the two native species in the same genus.
Nymphoides species have escaped from the ornamental plant trade over the past decade and become established in South Florida canals. The native Nymphoides species (N. aquatica and N. cordata) are usually found in shallow wetlands and littoral areas of lakes and not considered a problem.
The exotic N. cristata and Nymphoides indica are widely sold in the nursery and water garden trade and come from Asia. Of these, N. cristata is rapidly spreading. It occurs in south Florida canals, stormwater treatment areas, several central Florida canals, and north into South Carolina in the Santee-Cooper reservoir. It has become a serious weed problem in south Florida canals. The introduced species may look just as lovely, but it quickly covers the water surface with a canopy of leaves and shades out the plants below.
Plants have been confirmed in Broward, Collier (in Big Cypress National Preserve), Hillsborough, Lee, Orange, Palm Beach, Sarasota, Osceola, and St. Johns Counties (Wunderlin 2011). In 2010, it was found growing in scattered locations in Lake Okeechobee (Renney, personal communication 2011).Out of state, it is found growing abundantly in Lake Marion, South Carolina.