Limnanthemum peltatum S.G. Gmel., Nymphoides nymphaeoides (L.) Britton, yellow floating-heart, yellow floatingheart, floating heart, fringed water lily, entire marshwort

Stem/Roots: Nymphoides peltata is a rooted, perennial species with long branched stolons (up to 2 meters) that lie just below the water surface. Multi-leaved "plantlets" are produced at the nodes along with roots.

Leaves: Leaves are floating, round to heart-shaped (cordate) (3-12 cm in diameter) which resemble those of waterlilies (Godfrey and Wooten 1981; Newman 2000). Leaves are green to yellow-green and have slightly wavy margins. Undersides of leaves are often purple. 

Flowers: Two to five bright yellow, five-petaled flowers (2-4 cm in diameter) arise from each node as simple umbels with shallowly fringed petals borne above the water surface. Plants flower between May and October depending on water temperature (Godfrey and Wooten 1981; Sivarajan and Joseph 1993). 

Fruit/Seeds: Each flower produces one beaked capsule (2.5 cm), dispersing few to many smooth, flat, shiny seeds with margins of stiff hairs (Sivarajan and Joseph 1993).

Look-a-likes: Nymphoides cordata little floatingheart; Nuphar variegata yellow water lily

• Arizona: Guevavi Ranch Pond in Upper Santa Cruz drainage (University of Arizona Herbarium 2008)
• Arkansas: Lake Wedington in Illinois drainage (Stuckey 1973)
• California: Trout Lake in South Fork American drainage (Consortium of California Herbaria 2014) 
• Connecticut: Housatonic (Center for Invasive Species and Ecosystem Health 2015), Lower Connecticut, Shetucket (University of Connecticut 2011), and Quinebaug (Northeast Aquatic Plant Management Society 2009) drainages
• District of Columbia: US Fish Commission ponds in Middle Potomac-Anacostia-Occoquan drainage (Stuckey 1973)
• Florida: Near Lake Livingston and an Orlando retention pond in Kissimmee drainage (University of Connecticut 2011)
• Idaho: Emmett Park pond and the Payette River in Payette drainage (Center for Invasive Species and Ecosystem Health 2015)
• Illinois: Cahokia-Joachim (Missouri Botanical Garden 2007), Lower Rock (Stuckey 1973), Middle Wabash-Busseron, Shoal (Loyola University Chicago 2013), and Upper Kaskaskia (University of Connecticut 2011) drainages
• Indiana: Maxinkuckee Conservation Club pond in Tippecanoe drainage (Stuckey 1973)
• Louisiana: in Gretna in East Central Louisiana Coastal drainage (Stuckey 1973)
• Maine: private pond in Maine Coastal drainage (Center for Invasive Species and Ecosystem Health 2015)
• Massachusetts: Charles, Nashua, and Westfield drainages (IPANE 2001)
• Michigan: University of Michigan Dearborn Environmental Study Area pond in Detroit drainage (Kucher 2015)
• Mississippi: small private pond in Hattiesburg of Lower Leaf drainage (Stuckey 1973)
• Missouri: Cahokia-Joachim and Upper St. Francis drainages, and Newton County (Stuckey 1973)
• Nebraska: Benson Park Lake in Omaha of Big Papillion-Mosquito drainage (Steve Schainost, NE Game and Parks Commission, pers. comm.)
• New Jersey: Elmer Pond in Elmer of Cohansey-Maurice drainage (Stuckey 1973)
• New York: Hudson-Hoosic, Lower Hudson, Middle Hudson, Mohawk, Rondout (Stuckey 1973), Lake Champlain, Southern Long Island (Scott Kishbaugh NY DEC, pers. comm.), Lake George, and Mettawee River (Anderson 2009) drainages
• North Carolina: pond South of Crows Creek of Haw drainage (Wright et al. 2006)
• Ohio: Conneaut River of Chautauqua-Conneaut drainage (Mills et al. 1993), and Delaware (Cooperrider 1995) County
• Oklahoma: Bois D'arc-Island (Nelson and Couch 1985), Lower Washita, and Upper Little (Stuckey 1973) drainages
• Oregon: Applegate (Freeman 2008), Mckenzie, North Umpqua (Glen Miller, OR Dept. of Ag., pers. comm.), Tualatin (Center for Invasive Species and Ecosystem Health 2015), and Upper Willamette (iMapInvasives 2012) drainages
• Pennsylvania: Middle Delaware-Musconetcong (University of Connecticut 2011), Schuylkill (Stuckey 1973), and Upper Susquehanna-Tunkhannock (Pennsylvania Flora Database 2011) drainages
• Rhode Island: Tiverton Four Corners of Narragansett drainage (IPANE 2001)
• Tennessee: Lake Cheston in Sewanee of Upper Elk drainage (Center for Invasive Species and Ecosystem Health 2015), and Montgomery and Stewart Counties (USDA 2008)
• Texas: College Station of Navasota drainage, and San Patricio County (USDA 2008)
• Vermont: Lake Champlain (Stuckey 1973), Mettawee River (Countryman 1970), and Otter Creek (University of Alabama Biodiversity and Systematics 2007) drainages
• Virginia: private farm pond of Middle Potomac-Anacostia-Occoquan drainage (Wright et al. 2006), and Rappahannock County (Virginia Botanical Associates 2007)
• Washington: Hangman, Lower Columbia, Lower Willamette, Nooksack (University of Washington Burke Museum 2007), Lower Spokane (Stuckey 1973), Lower Yakima (Parsons 2007), and Strait of Georgia (University of Connecticut 2011) drainages 
• Wisconsin: Lake Gordon of Peshtigo drainage (Michigan State University 2015), and UW-Madison Botany Pond of Upper Rock drainage (Wisconsin Dept of Natural Resources 2010)

The small fruits contain hairy seeds that float in the water and can attach to animals (Benson et al. 2004, IL DNR 2005). Research by Cook (1990) shows dispersal mechanisms may include transport by waterfowl as well as chain-like rafts of floating seed. This species can also reproduce vegetatively; plant fragments (from nodes and leaves) and rhizomes can develop into new plants (MISIN 2013, OSIAP 2013).

Summary of species impacts derived from literature review. Click on an icon to find out more...

Environmental	Socioeconomic	Beneficial

The reduction in native plant species degrades the habitat and may reduce access to food for fish and wildlife (IL DNR 2005, OISAP 2013). If the population of yellow floating heart is large enough, fish and other wildlife may be forced to relocate (CEH 2004).
Dense stands of N. peltata can cause slow-moving water to become stagnant and the water beneath the mats to have a low oxygen concentration (DiTomaso and Healey 2003, IL DNR 2005, Lui et al. 2010, WI DNR 2012). Dense surface mats of N. peltata can hinder the air exchange between the water’s surface and the atmosphere (Kelly and Maguire 2009). These areas of stagnant waters can be an ideal location for mosquitos to breed (OISAP 2013).

Potential:
In large populations of yellow floating heart, sedimentation levels increase and could alter nearby hydrology (Kelly and Maguire 2009). In New England, dense stands of N. peltata have blocked waterways (IPANE 2013).

There is little or no evidence to support that Nymphoides peltata has significant socio-economic impacts in the Great Lakes.
Potential:
In locations outside the Great Lakes, dense mats of yellow floating heart have interfered with or even prevented recreational boating, canoeing, angling, water skiing, and swimming (CEH 2004, Lui et al. 2010, WI DNR 2012). The reduction in aesthetic and recreational value can lead to a decline in nearby waterfront property (Kelly and Maguire 2009).

Nymphoides peltata has a moderate beneficial effect in the Great Lakes.
Realized:
Nymphoides peltata is a popular ornamental plant for outdoor water gardens and is easily purchased via the internet or by mail-order (Benson et al. 2004, IL DNR 2005, OISAP 2013).

Potential:
Nymphoides peltata has the ability to move nitrogen and phosphorus up from the sediment into the aboveground biomass and back down into the root structure during the winter. This ability regenerates the nitrogen and phosphorus levels in the sediment (Brock et al. 1983).

The Great Lakes Life & Wildlife Commission has not found N. peltata in their ceded territories, but recommend immediate control upon detection (Falck and Garske 2003).

Nymphoides peltata is restricted in Ontario (regulatory amendments to Ontario Regulation 354/16 under the Invasive Species Act, 2015).

Note: Check federal, state/provincial, and local regulations for the most up-to-date information.

Control

Biological
There are no known biological control methods for this species (CEH 2004).

Physical
Hand-pulling and mechanical removal is possible because the stems are easily cut by hand tools (CEH 2004, MISIN 2013). Hand raking or using a rope and grapnel is effective when the bottom sediments are loose (CEH 2004). All plants pieces should be removed because new plants can grow from broken fragments and/or the decomposing plant material could decrease the oxygen levels in the water (CEH 2004, Kelly and Maguire 2009). Booms or nets can be used to catch and remove drifting plant materials (Kelly and Maguire 2009). Even with multiple harvests, 100% control is unlikely (CEH 2004).

Chemical
Aquatic labeled formulations of herbicides containing the active ingredient glyphosate provide best herbicide control for this speices.  The herbicide must be applied to the leaf surface when there is a minimal chance of rain or wave washoff.  Requires at least 4-6 hours of contact time to ensure optimal control.  Use of spray adjuvant is recommended. Usually requires several applications to be effective.  

Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.