Myriophyllum aquaticum

Parrot's feather

Family: Myriophyllaceae

Origin: South America

Close up of a cluster of parrot's feather in the water.
Parrot's feather can out-compete native aquatic plants and can reduce the holding capacity of stormwater ponds leading to flooding. It is usually controlled using herbicide safe to use in water.
Photo credit: Holly Cox

Regional Pest Management Plan (RPMP) status

  • Aotea — Exclusion
  • National Pest Plant Accord Species
  • Whole region — Sustained control

View more about the RPMP statuses

General description

Submerged, bottom-rooted, stoloniferous, sprawling aquatic herb. Leaves are finely divided, feathery, arranged in whorls of 4-6 and heterophyllous. Flowers are minute, female and produced in September – February.

What you need to know

To help protect our environment:

  • You must not breed, distribute, release or sell parrot's feather. As parrot’s feather is a National Pest Plant Accord species, these restrictions apply within the Auckland region and across the whole of New Zealand.
  • You must not plant parrot's feather within the Auckland region.
  • You must destroy any parrot's feather on land that you occupy if it has been planted in breach of the above rules and you are directed to do so by an authorised person.

If you see parrot's feather anywhere on Aotea/Great Barrier Island group, please report it to Auckland Council at pestfree@aucklandcouncil.govt.nz.

Habitats

Still or slow-moving water bodies.

Dispersal

Vegetative spread from rhizome and stem fragments, dispersed by water movement. Human-mediated dispersal through contamination of machinery, boats and equipment.

Impact on environment

Displaces native plant species, decreasing native plant species’ richness. Decreases invertebrate abundance and diversity in invaded water bodies.

Control

Site Management

Follow up treated areas 3 times per year. Encourage natural regeneration of native plants or replant treated areas where possible after 2-3 treatments to establish dense ground cover and minimise reinvasion.

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: Rake up and pull out between November and January.

Disposal options: Leave onsite to rot down away from the water.

Biocontrol

Biocontrol is currently not available for this species.

Community agrichemical control recommendations

Certified Handler/Experienced agrichemical user: Follow up in summer after pulling out plants with a foliar spray of 100 ml glyphosate green per 10 L of water.

Foliar spray emergent foliage with 100ml glyphosate green per 10L of water in October/November. Respray before foliage reaches 50mm high approximately every month.

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

Parrot's feather floating in the water.
Parrot's feather prefers to root into the soft silts that form on the base of ponds and lakes and slow moving drains. It can re-grow from pieces of stems and stolons that break off during storms.
Photo credit: Holly Cox
Hand holding Parrots Feather stem.
An aquatic weed that generally grows under the surface of ponds, streams and lakes. Parrot's feather leaves are bright green and feathery and can sometimes grow above the water surface.