fringed water lily, yellow floating-heart
Vascular – Exotic
Herbs - Dicotyledons other than Composites
Floating leaved perennial aquatic plant with ‘lily’ shaped leaves and yellow flowers, that can develop dense stands in still and slow flowing waters.
Nationally eradicated, previously known from Whangaparaoa, Auckland and pond sites in Hamilton.
Only known from a farm dam and ornamental ponds, but also grows in slow flowing waters overseas.
Underwater stem creeping or floating near the surface with leaves and roots at each node. The leaves are laternately arranged on the stems or oppostiely arranged on the flower stalks. Leaves are almost round, with a scalloped margin, deep sinus, and up to 10 cm across. The upperside of the leaf is green, while the under side is purplish. Two to 5 flowers arise from a flower stalk. The flowers are golden with 5 petals and solid marginal wings, and are 3 to 5 cm in diameter. The fruit is a beaked capsule.
Yellow water lily (Nuphar lutea), marshwort (Nymphoides geminata), and water poppy (Hydrocleys nymphoides). Yellow water lily has very thick spongy stolons (up to 10 cm) and much larger floating leaves (up to 40 cm long and 30 cm wide). Marshwort has entire leaf margins compared with the scalloped leaf margins of fringed water lily and no purple blotches on the upperside of the leaf. Water poppy has an inflated mid-vein on the underside of the leaves.
October - April
Vegetative spread by stoloniferous growth and by floating seeds which are fringed with many bristles. Huge potential for spread because seeds are adapted for water bird dispersal. Also deliberate plantings.
Europe and Asia
Reason for introduction
Ornamental pond plant
Can be controlled manually, mechanically or herbicidally depending on situation.
National Pest Plant Accord species
This plant is listed in the 2020 National Pest Plant Accord. The National Pest Plant Accord (NPPA) is an agreement to prevent the sale and/or distribution of specified pest plants where either formal or casual horticultural trade is the most significant way of spreading the plant in New Zealand. For up to date information and an electronic copy of the 2020 Pest Plant Accord manual (including plant information and images) visit the MPI website.
Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA).
References and further reading
Champion et al (2012). Freshwater Pests of New Zealand. NIWA publication. http://www.niwa.co.nz/freshwater-and-estuaries/management-tools/identification-guides-and-fact-sheets/freshwater-pest-species.
DiTomaso JM, EA Healy (2003). Aquatic and riparian weeds of the west. University of California Agriculture and Natural Resources Publication 3421, 462pp.
WSDE (2001). An aquatic plant identification manual for Washington’s freshwater plants. Washington State Department of Ecology, 195pp.