What does it look like?
Water poppy looks like a water lily. It has thick, glossy, floating leaves attached to rubbery creeping stems and distinctive yellow flowers with a purple centre. The flowers have three petals and are up to 8cm across.
Water poppy can grow in still or slow-flowing water that is less than two metres deep, especially if the water is warm and well-lit. It is an aggressive coloniser of ponds, streams, farm dams and lake margins.
Why is it a problem?
Water poppy quickly forms mats that block waterways and drains, causing flooding. It is a particular threat to native species that cannot compete with its aggressive growth.
In New Zealand, water poppy is not thought to produce seed. It spreads from root fragments and new plantlets that are produced at the end of the growth season. These break away from the main plant and rise to the surface, where they are carried away by water movement to a new location before taking root in the mud.