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Orange sedge (Carex testacea)

Orange sedge is cultivated as a garden ornamental in temperate parts of Australia and has been recorded naturalised near Hobart, although those populations are thought to have been eradicated. It is regarded as a potential environmental weed in Tasmania and may also be naturalised in Victoria.

Key facts

Type: Weed, grass.

Native to: New Zealand.

Established in: TAS.

Other names: Carex, New Zealand sedge, Orange New Zealand sedge, Orange-green sedge.

Best time to act: Look for it when the elongated flower clusters are visible, and remove or treat plants before seed is produced.

Identification

  • It is a clump-forming sedge with narrow leaves that can show orange or copper tones.
  • Older foliage may be especially orange-brown, giving the plant a speckled appearance.
  • Its elongated flowering stems can trail along the ground and reach up to 3 m long.
  • The flower clusters are elongated and occur along the trailing stems.
  • Look-alike: It can be confused with the New Zealand sedges Carex buchananii, Carex albula and Carex flagellifera, and also resembles some native species.
  • Look-alike: These sedges can be difficult to distinguish when they are not flowering.

Where it grows

In Australia it is grown in temperate gardens and has been recorded naturalised near Hobart; it has the capacity to invade pastures, native grasslands and woodlands.

Why it matters

  • In Tasmania it is considered a potential environmental weed because it can invade pastures, native grasslands and woodlands.
  • Within its native range in New Zealand, it is regarded as a significant weed of pastures.

How it spreads

  • It is cultivated as an ornamental, which can provide a pathway for it to establish beyond gardens.
  • Avoid moving flowering or seed-bearing plants and any soil or plant material that may contain its seed.

Control options

  • For small plants, dig out the whole clump, including the crown and roots, and dispose of it so it cannot regrow or shed seed.
  • Use only herbicides registered for the target plant and the site, and follow the product label and any local requirements.
  • Revisit treated sites and remove regrowth or new seedlings before they produce seed.
  • If you find it outside cultivation, contact your state or territory biosecurity agency or local council for identification and advice.

Hygiene and washdown

  • Before leaving an infested site, remove soil and plant material from footwear, tools, machinery and vehicles.
  • Do not transport contaminated soil or plant material to clean areas.
  • 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: Permitted, not declared. Listed as a permitted organism in WA, so it can be brought in, but it is not a declared pest.
  • Tasmania: Declared weed. Property managers are required by law to control declared weeds, and their import and sale are prohibited.
  • 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.

  • Tasmania: Biosecurity Act 2019 (Tas), administered by Biosecurity Tasmania

Sources