Hawai'ian arrowhead

Hawaiian arrowhead is aquatic perennial herb that can grow up to one metre tall.

Description

• Plant dies back to underground parts over winter.

• Submerged leaves are narrow and strap-like, also produces floating oval leaves.

• Emerged leaves are glossy, and arrowhead shaped up to 16cm long.

• No flowers have been observed in New Zealand.

• Creeping runners have round walnut-shaped tubers growing on them.

• It spreads via seed and vegetatively from tubers, runners, and rhizome fragments.

• Habitats include static or slow-moving shallow freshwater like drains, streams, and pond margins.

What you need to know

Forms dense stands, displacing native aquatic vegetation. Traps sediment, infilling channels and blocking drainage ditches.

Management approach

Hawai'ian arrowhead is declared an unwanted organism by the Ministry for Primary Industries (MPI) because it is capable of causing harm to the natural environment, physical resources or human health in Aotearoa/New Zealand.

These species pose a high risk to our environment, economy, recreation, and cultural values.

Rules

Any species declared a pest, including unwanted organisms, cannot be sold or be in a place where plants are being sold. Pest plants cannot be propagated, bred, or multiplied, communicated, released, or cause to be released, or otherwise spread.

Control

Do not attempt to undertake control of Hawai'ian arrowhead yourself. Report any sightings to us.