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White weeping broom (Retama raetam)

White weeping broom is an aggressive invader that can threaten natural vegetation and is a particular concern in dry regions because it is highly drought tolerant. It can infest grazing land, reduce access and carrying capacity, and poison domestic animals.

Key facts

Type: Weed, shrub.

Native to: Northern Africa, western Sahara, Sicily and the Middle East.

Established in: NSW, SA, WA.

Other names: White broom, Ratamals.

Best time to act: Look for flowers from late winter to mid spring and treat plants before pods are shed in late spring to early summer.

Identification

  • A densely branching, grey-green shrub that grows to about 3 metres tall and may reach 6 metres across.
  • It has many slender, drooping branches and is leafless for most of the year; its leaves are tiny, about 5 mm long and 1 mm wide, and drop quickly.
  • White, pea-like flowers, 8 to 10 mm long, grow in clusters of 3 to 15 along the branches; the calyx is dark red-brown.
  • Its wide, egg-shaped pods are 10 to 15 mm across, hairless and initially fleshy, later becoming leathery and smooth or wrinkled.
  • Each pod contains one or two kidney-shaped seeds, about 6.5 mm long and 5 mm wide.
  • Look-alike: Retama monosperma is extremely similar in appearance and is also a potential weed.
  • Look-alike: It may be confused with White Spanish Broom (Cytisus multiflorus) or Scotch Broom (Cytisus scoparius); Retama has inflated pods that do not split explosively, and plants are leafless for most of the year.

Where it grows

In Australia it is naturalised particularly around and east of Adelaide, on the Yorke and Eyre peninsulas, and around and north of Perth, with limited occurrences in NSW, Queensland and Tasmania.

Why it matters

  • It can invade natural vegetation and shade out native plants, particularly in dry regions and during drought.
  • It may infest grazing land, obstruct stock access and reduce the carrying capacity of grazing lands by more than 5%.
  • It is generally unpalatable but toxic; eating it can intoxicate and kill domestic animals, and plant toxins can taint milk and poison nursing animals.
  • It can invade vegetation around communities, especially small coastal communities, and spread along roadsides.

How it spreads

  • It reproduces only from seed, with each plant producing hundreds of pods and larger plants producing up to thousands of seeds.
  • Seeds fall when pods split open and can be further spread by water; seeds may also spread from gardens into suitable surrounding environments.
  • A hard seed coat delays germination, and seeds can remain viable in the soil for several years or more; the plant is not known to sucker.

Control options

  • Coordinate control with the relevant state or territory weed management agency or local council, and monitor treated areas for many years to destroy new plants.
  • Physical removal can suit isolated plants, especially before they have seeded; seedlings can be difficult to hand pull, so tools may help.
  • No herbicides are registered for White Weeping Broom; follow state or territory guidance and herbicide label information for any approved methods used on other brooms.
  • Bulldozing can spread seeds and disturb soil, while fire is generally not recommended in Australia because of out-of-control fire risk and the need for prolonged follow-up.

Hygiene and washdown

  • Seeds can be spread by water and persist in soil, so avoid moving seed-bearing material or potentially contaminated soil from infested sites.
  • Check and clean equipment and gear before leaving an infested area to reduce the chance of moving seeds.
  • 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): National Environmental Alert List. One of 28 weeds named on the National Environmental Alert List as early-stage invaders with serious potential to harm the environment.
  • 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: 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.

  • New South Wales: Biosecurity Act 2015 (NSW), administered by NSW Department of Primary Industries and Regional Development
  • 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