Alisma plantago-aquatica

Water plantain

Family: Alismataceae

Origin: Africa, Australia, Eurasia

Water Plantain emerging from water surface with young flower spike.
If water plantain is spotted in Aotea / Great Barrier Island, you must report it to Auckland Council. Dense plant parts can impede water flows and trap debris, increasing the chance of flooding.
Photo credit: Jackie Miles and Max Campbell

Regional Pest Management Plan (RPMP) status

  • Aotea — Eradication
  • Hauraki Gulf Controlled Area Notice pest

View more about the RPMP statuses

General description

Emergent, perennial aquatic herb < 1 m tall. Leaves are basal, < 10 x 20 cm and broad ovate, with a long petiole. Flowers are pale lilac/pink/red/white and borne on large, multi-branched panicles in summer. Achenes are held in a dense circular head and produced in summer-autumn.

What you need to know

To help protect our environment:

  • You must not breed, distribute, release or sell water plantain on Aotea/Great Barrier Island group.
  • You must not plant water plantain on Aotea/Great Barrier Island group.

Auckland Council will control water plantain at all sites within the Aotea/Great Barrier Island group where it is known to occur.

If you see water plantain anywhere on Aotea/Great Barrier Island group, please report it to Auckland Council at


Still or slow-moving water body margins, wetlands.


Seeds dispersed by waterfowl and water movement.

Impact on environment

Potential to displace native species. Impedes water flow and traps debris, causing silt build-up. May exacerbate flooding.


Site Management

Consider engaging an aquatic pest plant control operator. Contact Auckland Council for control options.

Recommended approaches

Do not attempt to undertake control of this species on Aotea/Great Barrier Island group. Please report to Auckland Council if seen on Aotea/Great Barrier Island group.

Physical control

Method: Dig out.

Plant parts requiring disposal: All parts.

Disposal options: Remove to greenwaste or landfill.


Biocontrol is currently not available for this species.

Community agrichemical control recommendations

Certified Handler/Experienced agrichemical user: Foliar spray of 100 ml glyphosate green per 10 L of water.

Caution: When using any herbicide or pesticide please read the label thoroughly to ensure that all instructions and safety requirements are followed.

Water Plantain emerging from water surface with young flower spike.
Water plantain is an aquatic weed that has the majority of its leaves just under the surface of the water. Seeds are carried to new waterways by flowing water and birds.
Photo credit: Antonie van den Bos,
Water Plantain plant in a plastic tray.
Plant can grow from fragments so care must be taken during removal. Water plantain can be transported on recreational boats if plant parts become trapped.
Photo credit: Doug Benson, Royal Botanic Gardens Sydney