Fringed water lily

Previously eradicated lily found in Tararua.

Nymphoides peltate (Fringed water lily), also known as Entire marshwort, yellow floating heart has been found in the Mangaone catchment.

Thought to have been eradicated in 1998, a recent eDNA test carried out by Mangaone River Catchment group indicated its presence. We need your help to stop it spreading. We are asking people to check their ponds for any unusual lilies or plants growing that have never been seen before.

While native in the UK, and its original spread from deliberate plantings, the origin of the lily in the Tararua is unknown. The weed poses a high risk of dispersal, and our freshwater does not need more invasive species.

Its unchecked growth can choke water bodies, outcompeting natives, and disrupting ecological balances. Swift action is imperative to preventing its further spread.

The discovery of the weed underscores the valuable role of community engagement in environmental stewardship and enabled the catchment to quickly deal with its discovery, working closely with Horizons who were proactive in allocating funding and tackling the issue head-on. Their view was this was an opportunity to eradicate the plant before it became a real problem. Under respected scientist and aquatic weed specialist Dr Paul Champion guidance the council proceeded to take the water away from the plant, disestablishing the pond in a way that didn’t cause any potential contamination or spread.

What you need to know

Perennial bottom-rooted aquatic herb. Stems are long, branched and creeping below the water’s surface, with adventitious roots. Leaves are floating, heart-shaped, < 15 cm in diameter and green, with purple undersides and scalloped margins.

Flowers are yellow, borne singly or in clusters on emergent stalks, and have fringed petals. Seed capsules are green, flattened and contain many hairy-edged seeds. The top of the leaf is green, while the underside is purplish in colour.

To help protect our environment:

You must not breed, distribute, release or sell fringed water lily. Fringed water lily is a National Pest Plant Accord species, these restrictions apply across the whole of New Zealand.

Habitats

Rivers, lakes, ponds, reservoirs, wetlands, dams, ditches.

Dispersal

Seeds dispersed by water and waterfowl. Human-mediated dispersal through deliberate plantings, ornamental pond escapes and movement of contaminated boats and equipment.

Impact on environment

Potential to form dense mats, outcompeting native vegetation and impeding access to waterways.

Control

Contact Horizon’s Biosecurity Plants Team on 0508 800 800