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Lippia (Phyla canescens)

Lippia forms dense mats that can dominate pasture and reduce grazing productivity. It is also a serious environmental weed in parts of the Murray-Darling system, where it can increase erosion and damage waterways.

Key facts

Type: Weed, herb.

Native to: South America (reported native range).

Established in: QLD, NSW, ACT, VIC, SA.

Other names: Carpet weed, Fogfruit, No-man grass, Condamine couch.

Best time to act: Lippia flowers in spring, summer and autumn when soil moisture is favourable, and control with herbicide alongside mechanical methods may be more effective while plants are actively growing and soil moisture is good.

Identification

  • A fast-growing perennial herb that forms dense, low mats along the ground, sometimes reaching 20 to 30 cm tall when competing with other plants.
  • Stems are green to purple when young and can become grey and woody with age; roots grow from leaf joints and the plant develops a woody taproot up to 2 metres deep.
  • Leaves grow in pairs, are 10 to 30 mm long and 3 to 7 mm wide, and have fine greyish hairs and blunt teeth near the tip.
  • Small flowers grow in tight heads about 10 mm across on stalks 15 to 45 mm long; they range from white or cream to purple, pinkish or pale lilac.
  • At maturity, the small fruits release two tiny, brown, oval, flattened seeds.
  • Look-alike: Phyla nodiflora is similar, but its leaves lack the fine grey hairs and have sharper, more pronounced teeth; Lippia leaves are hairy and have blunt, short teeth.

Where it grows

In Australia it occurs in temperate and subtropical areas, especially floodplains, seasonally wet open ground, waterways and adjacent higher ground, across NSW, Queensland, South Australia, Victoria and Western Australia.

Why it matters

  • Dense infestations can out-compete pasture plants, reduce pasture productivity and stocking rates, and provide little grazing value.
  • Sheep grazing on Lippia can develop copper deficiency, which can reduce wool quality.
  • Loss of perennial grasses and plant diversity can increase soil erosion and reduce stream-bank stability.
  • Its deep roots can contribute to banks breaking away into waterways, and dense growth can prevent other riparian vegetation from establishing.

How it spreads

  • Lippia spreads both by seed and vegetative fragments, with much of its spread occurring during floods.
  • Seeds can remain viable for many years; wet conditions, light and fluctuating temperatures can support germination.
  • Fragments and seeds can also be carried by vehicles, machinery and animals.

Control options

  • Long-term management is best approached by combining herbicides, mechanical control, pasture improvement and grazing management over many years.
  • Registered herbicides can suppress Lippia, but no herbicide provides long-term control; multiple applications within a season have given better suppression than a single application.
  • Ploughing or harrowing may provide short-term control in paddocks, but is unsuitable on creek banks and other riparian sites because of erosion and soil-loss risks.
  • Avoid herbicide use in riparian areas where it could pollute waterways, and establish new pasture grasses before grazing them.

Hygiene and washdown

  • Wash machinery used in infested areas before it leaves, as machinery can spread Lippia.
  • 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: Not declared. Not a declared weed in Tasmania. Other laws may still apply.
  • Northern Territory: Check NT list. There is no NT weed profile for it. Check the NT declared weeds list for its current status.
  • 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.

  • Queensland: Biosecurity Act 2014 (Qld), administered by Biosecurity Queensland (13 25 23)
  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development
  • Australian Capital Territory: Biosecurity Act 2023 (ACT), administered by ACT Biosecurity
  • Victoria: Catchment and Land Protection Act 1994 (Vic), administered by Agriculture Victoria
  • South Australia: Landscape South Australia Act 2019 (SA), administered by the regional landscape board

Sources