Also known as
Where is it originally from?
What does it look like?
Perennial waterlily-like plant with thick, shiny, oval, bright green leaves (7 cm long) that float on the water surface and have an inflated main vein on the underside. Leaves and roots grow in clusters from nodes along the stems, which float just below the water surface. A distinctive poppy-like, three-petalled yellow flower with a purple centre (<8 cm across) is produced from November to April.
Are there any similar species?
Yellow water lily (Nuphar lutea) has thick spongy underwater stems (<10 cm) and larger leaves (<30 cm wide x 40 cm long). Marshwort (Nymphoides geminata) and fringed water lily (N. peltata) do not have an inflated main vein on underside of leaf, and they have wings on the outer edges of their petals.
Why is it weedy?
Rapid growth rate, covers waterbodies by developing a dense mat of stems.
How does it spread?
Spreads by plantlets or stem fragments carried by water, boats, fishing gear or machinery. No seed is produced in New Zealand.
What damage does it do?
Dense growth chokes streams, shallow ponds and lake margins, causing flooding. Shades out other plants, reduces nutrient availability, and alters the habitat for other organisms.
Which habitats is it likely to invade?
Still or slow-flowing water less than 2 m deep. Prefers open, warm, nutrient rich conditions, but will tolerate cool climates.
What can I do to get rid of it?
Contact your Regional Council if you think you have found this plant.