Mexican water lily

Mexican water lily is a bottom-rooted, aquatic weed that roots into the soft sediment at the bottom of lakes and ponds.

Description

• Leaves are floating, round, heart-shaped, and 20cm in diameter.

• When leaves mature they have brown flecks on top, with a pink/purple underside.

• Fleshy stems (stolons) have banana shaped tubers that are creeping.

• Flowers are star-shaped, yellow, and 15cm in diameter. They appear above the water surface between October-December.

• Rhizomes are stout and erect.

• Fruit is spherical to ovoid, 2.5cm in diameter, and ripens in summer-autumn.

• Rhizomes, tubers, and seeds are spread by water and fragments via boats, fishing gear, or machinery.

• Habitats include still and slow-moving freshwater bodies.

What you need to know

Mexican water lily forms dense mats and may displace submerged aquatic plants. It reduces dissolved oxygen levels, affecting fish, zooplankton and other native species.

Management approach

Mexican water lily is declared an unwanted organism by the Ministry for Primary Industries (MPI) because it is capable of causing harm to the natural environment, physical resources or human health in Aotearoa/New Zealand.

These species pose a high risk to our environment, economy, recreation, and cultural values.

Rules

Any species declared a pest, including unwanted organisms, cannot be sold or be in a place where plants are being sold. Pest plants cannot be propagated, bred, or multiplied, communicated, released, or cause to be released, or otherwise spread.

Control

Do not attempt to undertake control of Mexican water lily yourself. Report any sightings to us.