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Common cord-grass (Sporobolus anglicus)

Common cord-grass is a highly successful invasive plant in intertidal and saline to subsaline coastal areas of southern Australia. It transforms saltmarsh, mangrove and beach habitats, affecting wading birds and small molluscs and crustaceans.

Key facts

Type: Weed, grass.

Native to: Europe; the fertile hybrid arose in Hampshire, the Isle of Wight and northern France..

Established in: VIC, TAS.

Other names: Rice Grass, Cord Grass, Spartina.

Best time to act: Common cord-grass flowers from December to March, and seed can mature as late as June.

Identification

  • It is a deep-rooted perennial grass that starts in clumps and can spread into extensive swards.
  • Its smooth, hairless leaves are flat or folded, taper to a hard point, and can reach 45 cm long and 15 mm wide.
  • Erect flowering stems are 30–130 cm tall and bear 2–6 yellowish spikes, each up to 25 cm long.
  • The flowers are arranged in two rows along the flower stem; Common cord-grass has fertile anthers longer than 8 mm.
  • Look-alike: Spartina × townsendii is similar, but its anthers are up to 8 mm long and contain no fertile pollen; Common cord-grass has larger, fertile anthers.
  • Look-alike: Native Common Reed (Phragmites australis) can resemble it before flowering, but is generally taller, has broader leaves on an erect hollow stem, and has a feathery flower head when in flower.

Where it grows

In Australia it occurs in coastal saltmarshes, mangrove shrublands, mudflats, and the edges of tidal streams and channels in Tasmania and Victoria.

Why it matters

  • It transforms saltmarsh, mangrove communities and sandy beaches into dense Spartina meadows.
  • Wader-bird use of invaded areas can decline, and changes to habitat structure and food availability can affect fauna that depend on small crustaceans and molluscs.
  • It can make boating and boat-launching facilities inoperable through sediment accretion, affect intertidal oyster farming, and change hydrodynamics.

How it spreads

  • It spreads by seed, which can survive immersion in seawater for considerable periods.
  • Water can disperse plant fragments and rhizomes to new sites; moved rhizome sections, known as runners, have also spread it in the past.
  • Seedlings may establish soon after dispersal, and seeds may remain viable for considerable periods before germinating.

Control options

  • Hand-weeding is suitable only for small infestations, as it can fragment rhizomes that may establish elsewhere.
  • Opaque plastic sheeting left in place for several months can kill up to 100% of plants in small infestations, but can also destroy animals and plants beneath it.
  • Grazing reduces biomass but generally does not destroy the plants.
  • Grass-selective registered herbicides may provide good control; no biological control agent is listed.

Hygiene and washdown

  • Avoid moving seed, plant fragments or rhizome runners between sites, including on boats or equipment, as fragments can establish elsewhere and water can disperse them.
  • Inspect and clean vehicles, plant and footwear before leaving an infested area, paying attention to tyres, radiators, belly plates, tracks and floor mats.
  • Wash down at a designated bay where runoff is contained and can be monitored for seedlings.
  • Record each washdown so the client has evidence of clean entry and exit.

Classification by state

  • Australia (national): No national listing. Managed under state and territory law.
  • Queensland: Not prohibited or restricted. Not listed as prohibited or restricted matter in Queensland. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Not a priority weed. Not a state or regional priority weed in NSW. The general biosecurity duty applies: anyone dealing with it must prevent, eliminate or minimise the risk it poses.
  • Victoria: Not declared. Not declared under the Catchment and Land Protection Act 1994. Other Victorian laws may still apply.
  • South Australia: Not declared. Not declared under the Landscape South Australia Act 2019. Other laws may still apply.
  • Western Australia: Not listed. Not found in the Western Australian Organism List. Check with DPIRD before moving or keeping it.
  • Tasmania: Not declared. Not a declared weed in Tasmania. Other laws may still apply.
  • Northern Territory: Not declared. Not on the NT A to Z weed list, and Weeds Australia does not list it as declared in the NT. Check the NT declared weeds list before moving or planting it.
  • Australian Capital Territory: Not declared. Not declared under the Biosecurity Act 2023 (ACT). A general biosecurity duty still applies.

Legal obligations

Every state and territory places a duty on landholders and people working on land to prevent the spread of invasive species, such as the general biosecurity obligation in Queensland and the general biosecurity duty in New South Wales. Declarations and control requirements differ between states and local government areas, so check the current official list before work starts.

  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • Tasmania: Biosecurity Act 2019 (Tas), administered by Biosecurity Tasmania

Sources