Reed Canary Grass

(Phalaris arundinacea)

Progressive Control Pest

Reed Canary Grass is a tall perennial grass often found on the edge of waterbodies and growing up to 2 m tall with leaves up to 0.5 m long. The flowers are arranged in dense branched panicles up to 20 cm in length. It forms dense mats of rhizomes which produce large numbers of shoots. A native of North America, it has spread through parts of New Zealand where wet moist conditions prevail; it is tolerant of freezing conditions.

Reasons for the Strategy

Reed canary grass in a field.

Reed Canary Grass is an internationally renowned weed of wetlands, where it forms dense sprawling stands up to 1m tall that smother and impede the regeneration of other vegetation. The dense mats that impede access and drainage, causing silt accumulation and flooding. It can replace other aquatic margin vegetation and degrade habitat for aquatic fauna. It has the potential to take over wetland margins and the margins of other waterbodies and drains and represents a significant threat to wetlands in the Tasman-Nelson region. It can be spread by seed or rhizome fragments in mud on machinery, footwear, and livestock or in water.

Reed Canary Grass is tentatively assessed at “2” on the infestation curve. Given its limited distribution, the importance of remnant wetlands, and its potential impact on wetlands, placing it into Progressive Control will provide benefits that outweigh the costs.


To reduce the distribution and density of Reed Canary Grass in the Tasman-Nelson region during the term of the Strategy.

Alternative Measures

The option of “do nothing” or relying on voluntary control will not achieve the objective of reducing the density and distribution of Reed Canary Grass, and could result in significant loss of indigenous biodiversity and increased costs of control in the future. Requiring total control is not considered appropriate at this time with limited nformation on its distribution.

Strategy Rule for Reed Canary Grass

The occupier shall destroy all adult and juvenile forms of Reed Canary Grass on land in the Tasman-Nelson region that they occupy. A breach of Strategy Rule 5.x.5 is an offence under Section 154(r) of the Biosecurity Act 1993.

Biosecurity Act Requirement

No person shall knowingly sell, propagate, breed, release or display commercially, Reed Canary Grass, under Sections 52 and 53 of the Act.