Hydrocleys nymphoides

Common Name(s)

Water poppy


Hydrocleys nymphoides (Humb. et Bonpl.) Buchenau



Brief Description

Stoloniferous perennial with tufts of thick glossy, floating leaves attached to rubbery creeping stems and a distinctive showy yellow flowers with a purple centre.

Flora Category

Vascular - Exotic

Structural Class

Monocotyledonous Herbs


Locally naturalised in northern North Island south to the Rotorua lakes, eradicated from most known sites.


Still and flowing water bodies, including ponds, streams and lake margins to ca 2m water depth.


Underwater stem is elastic, creeping, or floating near the water surface. Leaves and roots attached at each node along the stem. Leaves are bright glossy green, oval, 7 cm long, and have an inflated main vein on the underside. The leaf sinus is shallow. Flowers consist of 3 yellow petals with a purple centre (filaments) and are up to 8 cm across.

Similar Taxa

Yellow water lily (Nuphar lutea), marshwort (Nymphoides geminata), and fringed water lily (Nymphoides peltata). 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 and fringed water lily do not have an inflated mid-vein on the underside of the leaves. They also have wings on the outer edges of their petals.


Late summer

Flower Colours



No seed production known in NZ

Year Naturalised



Tropical South America.

Reason for Introduction

Ornamental pond plant

Control Techniques

Notify regional council if found

Life Cycle and Dispersal

Vegetative spread by stolon fragments, deliberate planting. Water poppy produces new plantlets 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 (Ermert & Clapp 1998)


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.

Coffey BT, Clayton JS (1988).  New Zealand water plants:  a guide to plants found in New Zealand freshwaters.  Ruakura Agricultural Cente. 65pp.

Johnson PN, Brooke PA (1989).  Wetland plants in New Zealand.   DSIR Field Guide, DSIR Publishing, Wellington. 319pp.

Kasselmann C (2003).  Aquarium plants. Krieger Publishing company, Florida, 518pp.;                     

This page last updated on 21 Aug 2013