What does it look like?
Yellow water lily is a perennial aquatic plant, with both floating and submerged leaves. Floating leaves are oval, up to 30cm long by 40cm wide, with a deep indent at one end. Leaves are tough, leathery, and dark green. Stout tuber-like rhizomes up to 10cm in diameter grow on the bottom to a depth of 3m. Stalked, solitary buttercup-like 4-6cm diameter flowers rise well above the leaves. Flowers have a strong alcoholic aroma. Fruit are 2-3cm long, green and flask shaped and contain hundreds of long-lived viable seeds.
Why is it a problem?
Yellow water lily grows from the water's edge into slow-running water up to 2m deep and can invade permanent water of lakes and slow-flowing streams over mud and silt. Fast growing, along with its massive rhizomes that hold nutrient stores, enables it to outcompete all other aquatic plants.
Control methods
If you have seen or suspect the presence of yellow waterlily, you must report the sighting to us immediately.
More information
As of 2024, yellow water lily is considered eradicated from Hawke’s Bay. Previously, it only occurred in two sites in the Elsthorpe area.
Related links
- Hawke’s Bay Regional Council Pest Management Plan 2018-2038
- NPPA and the control of weeds | NZ Government
Notify Council
If you think you've found this pest, please get in touch with our Biosecurity Team at biosecurity@hbrc.govt.nz or call us on 0800 108 838.
Management Programme
Eradication Programme
An Eradication Programme attempts to reduce a pest's level of infestation to zero, across an infestation zone, over a specified time frame. To be successful; the rate of removal must exceed the rate of increase of the pest, reinvasion from other areas must be prevented, and all potentially reproductive individuals must be targeted. For these reasons, eradication programmes require robust design, efficient implementation, sufficient money, and trained field staff to be successful.
More informationNational Pest Plant Accord
All plants on MPI's National Pest Plant Accord (NPPA) are unwanted organisms under the Biosecurity Act 1993 whose formal or casual trade contributes significantly to their spread.
Plants on the Accord cannot legally be propagated, distributed, or sold in New Zealand. If allowed to spread further, these pest plants could seriously damage our economy and environment.
Unwanted Organism
An unwanted organism is any organism that's capable of causing harm to natural or physical resources (like forests and waterways) or human health. A number of introduced pests in New Zealand are classed as unwanted.
More informationRules
Sections 52 and 53 of the Biosecurity Act (1993)
No person shall knowingly communicate, cause to be communicated, release, or cause to be released, or otherwise spread any pest or unwanted organism, in accordance with Sections 52 and 53 of the Biosecurity Act 1993
More informationTaxonomies
TypePlants
GroupFloating
HabitatFreshwater
Management ProgrammeEradication ProgrammeNational Pest Plant AccordUnwanted Organism
