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Small-flowered tamarisk (Tamarix parviflora)

Small-flowered tamarisk is a non-native tamarisk with weedy tendencies reported in New South Wales and Western Australia. Tamarisks can damage riverine environments and pastoral land, and infestations can be difficult and costly to control.

Key facts

Type: Weed, tree.

Native to: Southeastern Europe and the eastern Mediterranean.

Established in: NSW, VIC, SA, WA.

Other names: Tamarisk, Four-stamen tamarisk, Tamarix parviflora.

Best time to act: Spring flowering can help crews locate and identify plants; plan treatment for conditions suitable for the chosen method and follow local advice and herbicide label directions.

Identification

  • A deciduous shrub or small tree with slender, arching branches.
  • Its tiny, scale-like leaves closely clasp the stems.
  • Small pink flowers grow in dense spikes, usually in spring.
  • The flowers have four stamens, a useful feature for distinguishing this species from some other tamarisks.
  • Look-alike: Athel pine (Tamarix aphylla) is another introduced tamarisk, generally a larger tree with jointed branches and minute leaves; its flowers are usually white to pink and appear in summer.
  • Look-alike: Native she-oaks can also have a fine, needle-like appearance, but have segmented branchlets and hard, woody fruit resembling small cones.

Where it grows

In Australia it is associated with inland and riverine areas, including infestations reported on the Gascoyne and Avon Rivers in Western Australia, and it can grow in saline conditions.

Why it matters

  • Tamarisks can form dense stands along rivers and use water that would otherwise be available to native plants and watering sites.
  • They can increase soil salinity beneath plants, disadvantaging salt-sensitive native vegetation.
  • Infestations can alter vegetation and river structure, contribute to erosion or flooding, and hinder mustering.
  • The guide identifies Tamarix parviflora as a weedy tamarisk with potential impacts similar to athel pine.

How it spreads

  • Tamarisks produce small seeds that can be carried by wind and water; water movement can help spread them along rivers.
  • Plant material may also be moved by floods, so avoid transporting potentially viable fragments or contaminated soil.
  • Check waterways and nearby disturbed areas for new plants, particularly downstream of known infestations.

Control options

  • Remove small seedlings by hand where the soil allows, taking care to remove roots and avoid leaving viable plant material behind.
  • For established trees, use an appropriate physical or chemical method suited to the site; cut-stump or stem-treatment methods may be options where permitted.
  • Use only herbicides registered for the target and site, follow the product label, and take particular care near waterways and non-target vegetation.
  • Revisit treated areas to control seedlings and regrowth, and contact the relevant state or territory biosecurity agency or local council for site-specific advice.

Hygiene and washdown

  • Clean soil and plant material from machinery, vehicles, boots and tools before leaving an infested site, and dispose of the material where it cannot spread.
  • Avoid carrying plant fragments or contaminated soil along waterways, and clean waterway equipment before moving to another site.
  • 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: Declared plant. Depending on the declaration, it can be an offence to move it on public roads or sell it, and landowners may be required to control it on their land.
  • 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.

  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development
  • 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
  • Western Australia: Biosecurity and Agriculture Management Act 2007 (WA), administered by the WA Department of Primary Industries and Regional Development

Sources