Species Overview

Native to: Southeastern Asia

Due to its attractive appearance, crested floatingheart has long been grown as a water garden ornamental. The species was first discovered in the wild in 1996, when it apparently escaped cultivation in southwest Florida, invaded the lake of a residential subdivision, and quickly spread throughout the drainage canals. By 2001, crested floatingheart had spread north to Sarasota and east to Palm Beach County and is now broadly distributed throughout the state, which spurred its addition to the Florida Noxious Weed List in 2014. The species was found in South Carolina’s Santee Cooper system in 2006 and continues to be one of the most vexing problems for resource managers there. In addition to Florida and South Carolina, active invasions of crested floatingheart exist throughout the southeastern United States (Biology and Control of Aquatic Plants: 2.9 Floatinghearts). 

Species Characteristics

Family: Menyanthaceae

Habit: rooted in the substrate and produce leaves and flowers that float on the surface of the water.

Leaves: heart-shaped; the upper surface is green, usually with a red margin, and the underside is smooth and reddish. Form at the terminus of long floating stems. Up to 8 inches long, and 6 inches wide.

Flowers: white, with yellow throats, five-petaled, and have a distinct erect fold of petal tissue, or “crest,” along the midvein of the upper surface of each petal lobe, up to 1 inch across.

Fruit: capsules (6 mm long) and contain up to 20 seeds.

Reproduction: primarily via spiky ramets, which float through the water column and eventually sink to the bottom where they can root and sprout to form new plants. A single founder plant can produce as many as 500 ramets over six months and 40% of these are likely to sprout.

Distribution in Florida: Reported from 11 counties in peninsular Florida

Impacts

Impairs flood control structures by obstructing water flow.  Alters water chemistry and displaces native species.  It also has the potential to disrupt navigation and recreational activities.  Crested floatingheart has been documented hybridizing with native Nymphoides species in South Carolina which alters the genetic population and can complicate management options. 

Thoroughly clean boats, motors, and gear when moving from one water body to another.  Do not purchase for use in water gardens.

Water draw down can reduce the viability of ramets. 

mechanical control measures are not practical for managing crested floatinghearts because it can reproduce via stem and leaf fragments and are thought to have the capacity to regrow from root crowns that remain in the soil after harvesting plant material in the water column. In addition, crested floatingheart produces many ramets which are left behind after harvesting and can quickly sprout to repopulate the system.

No known biological control agents

Although both foliar and water-column treatments can be utilized to control large infestations, water-column treatments tend to have better efficacy. Contact herbicides such diquat and endothall and systemic herbicides such as imazamox, imazapyr, and auxins (2,4-D, triclopyr and florpyrauxifen-benzyl) have been used for management of floatinghearts with varying levels of success. As with other floating-leaved species, herbicide efficacy is influenced by environmental conditions such as currents and wave action. It is important to consult an expert for assistance in developing the most effective and integrated approach to management.