Spartina anglica, S. alterniflora
Also known as
American spartina, hybrid spartina, cord grass
Where is it originally from?
North America, England
What does it look like?
Perennial, clump-forming grass (<1 m) with rhizomes and fibrous roots and erect stems (4-9 mm diameter) with many brownish leaf sheaths. Alternate leaves (5-45 x 4-15 mm) are deeply wide-ribbed on upper surface and have ligules (1-3 mm long). Seedheads are occasionally seen, and seed is occasionally produced at some sites.
Are there any similar species?
Only grass species found in the inter-tidal zone apart from the small native non-grass Zostera. Tall fescue, couch and other grass species are similar to spartina but none of these are found in the intertidal zone.
Why is it weedy?
Colonises the bare inter-tidal zone where it forms dense clumps and traps sediment. Tolerates all weathers and temperatures, fire, grazing, and other damage. Rhizomes spread slowly and broken fragments resprout easily.
How does it spread?
Livestock, propellors, nets and so on dislodge rhizome fragments, which are then spread by tidal and current movement. Also spread through intentional planting. Can survive long-term at sea, which means that it can travel long distances with the currents.
What damage does it do?
Traps sediment, raising the level of the ground above the high tide mark and destroying the inter-tidal zone and habitat. Other weedy grasses succeed spartina, creating dry 'meadows'. It can reduce large estuaries and shallow harbours to thin drains surrounded by rough pasture, resulting in an immense loss of biodiversity.
Which habitats is it likely to invade?
Estuaries, mangroves and other intertidal zones with soft sediment.
What can I do to get rid of it?
Spartina is controlled by the Department of Conservation - contact your local office for more information.