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Paper mulberry (Broussonetia papyrifera)

Paper mulberry is an introduced, fast-growing tree recorded around Nimbin, Lismore and Upper Wilson’s Creek in northern NSW. It can outcompete native plants, form dense stands and produce pollen that causes allergic reactions in some people.

Key facts

Type: Weed, tree.

Native to: South-east Asia.

Established in: QLD, NSW.

Other names: Aute.

Best time to act: Treat with herbicide in spring and summer, when the plant is actively growing.

Identification

  • A deciduous tree that can reach 20 m tall, though it is usually less than 12 m.
  • Leaves are 6–18 cm long, oval or heart-shaped, toothed and often have 3–5 lobes on young plants; they are rough above and hairy underneath.
  • Male flowers are yellowish-white and hang in cylindrical spikes; female flowers are green and form round clusters.
  • The roundish, fleshy fruit is green when young and orange to reddish-purple when ripe, measuring 15–30 mm across.
  • Stems are pale brown and smooth or shallowly grooved, with horizontal trunk markings; small stems are densely hairy and reddish-brown, and broken stems exude milky sap.

Where it grows

In NSW it grows in riparian areas, forest and vine-thicket margins and gaps, and disturbed open sites such as unmanaged farmland.

Why it matters

  • It can outcompete native plants and form dense stands.
  • It can reduce habitat and food for native animals.
  • Its abundant pollen can cause allergic reactions in some people.

How it spreads

  • When male and female trees are present, fruit can form and seeds can be spread in the droppings of birds, bats and other animals.
  • Seeds can also spread in moving water and dumped garden waste.
  • Root suckers and new plants from broken plant parts can spread the tree; broken stems and roots can move in water or dumped garden waste.

Control options

  • Report suspected plants to the local council weeds officer for identification, control and removal advice.
  • Dig out young plants and remove as much of the root as possible to prevent regrowth.
  • Herbicides can be effective when applied in spring and summer while the plant is actively growing; follow the product label and any permit conditions.
  • For cut stump treatment, apply herbicide to the stump within 15 seconds of cutting; on larger plants, scrape the cut stem and above-ground roots and treat the scraped areas within 15 seconds.

Hygiene and washdown

  • Broken stems and roots can spread in moving water, and plant material can spread in dumped garden waste.
  • Avoid moving paper mulberry plant parts in water or garden waste.
  • 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: Restricted matter, categories 3, 5. Do not give it away, sell or release it into the environment; do not keep it. Everyone must also take all reasonable and practical steps to minimise its risks (the general biosecurity obligation).
  • New South Wales: Regional priority in 1 of 11 regions. Regional priority weed in North Coast. 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: Declared pest (C1), prohibited. C1 Exclusion: to be kept out of WA, or out of the parts of WA where it is not established. Report any sighting to DPIRD. It must not be brought into WA (prohibited organism).
  • 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

Sources