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Porcupine flower (Barleria prionitis)

Barleria forms dense, prickly thickets that can damage natural ecosystems and create problems for agriculture and recreation. It is difficult to eradicate once established, but early intervention can make it relatively easy to control.

Key facts

Type: Weed, shrub.

Native to: East Africa and tropical Asia.

Established in: QLD, WA, NT.

Other names: Barleria.

Best time to act: Look for seedlings after the first significant wet-season storms and target small infestations early, including newly emerged plants after mowing.

Identification

  • A robust, prickly shrub that grows up to 1.5 m tall.
  • Its hairless branches have 2 to 5 spines, each 10 to 20 mm long, at the base of leaves and branches.
  • The oval leaves grow up to 130 mm long and 40 mm wide, with smooth edges and a spine-tipped apex.
  • Yellow-orange, tubular flowers are about 40 mm long and grow in bunches at branch ends.
  • Hairless fruit capsules are about 18 mm long and contain two flat seeds covered in hairs that become mucilaginous when wet.
  • Look-alike: Barleria lupulina also has yellow flowers, but its leaves have a red midrib.

Where it grows

In Australia it occurs in the tropical north, including the Northern Territory, Queensland and Western Australia, in savanna, along river banks and in disturbed places such as roadsides and overgrazed pastures.

Why it matters

  • Dense, prickly thickets can be environmentally and economically damaging, and cattle do not eat the plant.
  • Thickets around waterways can impede the movement of cattle and other animals, and can provide refuges for feral animals.
  • In natural ecosystems it can be persistent and difficult to remove, becoming extremely vigorous with the onset of the wet season.
  • Its stems can cause injury, and infestations may restrict recreation and Indigenous peoples' access to natural resources.

How it spreads

  • Plants produce up to hundreds of seeds in a season; mature capsules can explode when wetted after a dry period and fling out the seeds.
  • Most seeds germinate within a few metres of the parent plant, but water can aid downhill spread and seeds may move more quickly along paths or roads.

Control options

  • Seek expert assistance before attempting control, as poorly performed or unfinished work can help spread the weed.
  • Chemical control can be effective; mowing followed by spraying newly emerged plants with a broadleaf herbicide is thought likely to work. Use registered herbicides only in accordance with their directions and expert advice.
  • For small populations, hand-pulling can be effective; wear gloves because the plant is spiny.
  • Dispose of pulled plants correctly and follow up to check for regrowth.

Hygiene and washdown

  • Treat Barleria garden waste before disposal, as the plant can probably grow roots from any node and discarded garden plants have started Australian infestations.
  • 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: 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: Declared weed. Weeds Australia lists it as a declared weed in the NT under the Weeds Management Act 2001. Check the NT declared weeds list for its class and what it requires.
  • 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)
  • Western Australia: Biosecurity and Agriculture Management Act 2007 (WA), administered by the WA Department of Primary Industries and Regional Development
  • Northern Territory: Territory Parks and Wildlife Conservation Act 1976 (NT), administered by NT Department of Lands, Planning and Environment

Sources