Mexican water lily
The Mexican water lily (Nymphaea mexicana) is originally from Mexico and south-east America. The species is an environmental weed but is not listed in Queensland's Biosecurity Act 2014. Once established, this plant can be difficult to eradicate.
It is a perennial lily that has dark green leaves with a reddish tinge, often blotched with brown. The underside of the leaf has distinct, fleshy venations. Its leaves have a wavy margin, are often concave and are usually crowded and overlap.
The flowers are bright yellow and emerge above the surface of the water. The plant has vertical knobbly rhizomes that take root in the substrate and produce new horizontal stems (stolons). If these stolons break, they can re-establish elsewhere.
Case Study: Robina Lakes
In the past, we have harvested some of the exotic lilies inhabiting the lakes. Where appropriate, native lilies, for example Snowflake Lily (Nymphoides indica), are left in the lakes. These provide food and habitat for aquatic organisms and help to maintain water quality.
Some exotic species, such as the Mexican water lily, can have a negative effect on aquatic environments and water quality, particularly if growth is left unchecked and they outcompete native species, dominating the environment.
Experience shows that harvesting the Mexican water lily is an unsustainable approach to managing it. Residents and council officers have observed rapid and thick regrowth of this lily in some patches in Robina South Lake shortly after harvest.
We have implemented an integrated management program for the control of the Mexican water lily in Robina South and West lakes. Initially, the locations of this invasive lily were mapped. A registered herbicides was subsequently applied to the foliage. Decaying plants were then mechanically removed as part of the aquatic vegetation harvesting program. We implemented a monitoring program to ensure there were no detrimental effects to the environment, such as off-target damage or water quality impacts from decomposing plant material.
Our Vector and Biosecurity Services team manages the application of herbicide on selected patches in Clear Island Waters and Robina South and West lakes. Officers are highly trained in the use of herbicides and use a product registered for use in aquatic environments.
Report a sighting
If you find a plant that resembles the characteristics of the Mexican water lily, click on the following button and scroll down to 'Pest plants' to complete our online form.
Report a problem – Trees, plants & vegetation