Parrots feather
Haloragaceae - Myriophyllum aquaticum

What does it look like?

Parrot's feather is a submerged, bottom-rooted perennial aquatic herb.  The top 10cm of foliage can be emergent, standing above the water. Sprawling foliage is pale grey-green, and stems are up to 2m long.  Leaves are finely divided, feathery, and arranged in whorls of 4-6.  Emergent and submerged leaves differ in form.  It flowers from September – February.  Only female plants are present in New Zealand so no seed is set. 

Still or slow moving water bodies including wetlands, lakes, streams, rivers, drains and ponds to a depth of approximately 5+m.  It is unlikely to be severely problematic in large exposed lakes.  Tolerates slightly brackish conditions.  Favours water bodies with high nutrient (especially nitrogen) and light levels.  Tolerates fluctuating water levels, including complete exposure of sediment.  Growth rates increase in response to increases in carbon dioxide.  May benefit from climate change.

Why is it a problem?

History of invasiveness overseas.  Taller growing form than native Myriophyllum species.  Rapid growth rate and highly variable growth forms. Allelopathic - releases chemicals that affect the growth of other species.  Growth from fragments provides competitive advantage in dynamic environments.

Does not set seed in New Zealand.  Grows from small fragments.

Control Methods

Please contact your local regional council's Biosecurity department for advice on controlling this plant.

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