Paper mulberry

Paper mulberry has recently been detected in Northern NSW and appears to be in an early stage of invasion. It is a deciduous tree that can grow up to 15m tall and has milky sap. It was once thought to be a useful plant, but it is now regarded as a weed. Paper mulberry (Broussonetia papyrifera), a native of Asia, was promoted in the 1980s as a permaculture species for paper making.

It is a significant invasive weed in several countries where it threatens local native vegetation. In addition to its environmental impacts, its pollen is thought to cause inhalant allergies in Islamabad (Pakistan), where it is listed among the country’s six worst plant invaders. In Ghana it escaped from cultivation and poses a threat to native vegetation communities.

With separate male and female plants and a habit of suckering profusely, this fast growing tree readily spreads. Birds and bats carry seed further afield and the plant can appear along creek banks, neglected gullies, roadsides and other disturbed areas, particularly after fire. Paper mulberry grows best in well-drained soils where rainfall exceeds 1,000mm a year. Its rapid growth and ability to sucker and form dense thickets give the weed a competitive advantage over native species and allow it to dominate.

Identification can be tricky as leaf shape is variable. It can be deeply-lobed, single lobed or not lobed at all.

  • Lobed leaves are more frequent on fast-growing young plants.
  • Leaves are alternate, opposite or whorled along the stem and between 8-20cm long.
  • The upper leaf surface is rough and the lower side has dense, soft hairs that distinguish it from similar native species.
  • When broken, the leaves exude a milky sap, which will stain clothing.
  • Male flowers are yellow-white and arranged in an elongated inflorescence up to 8cm long.
  • Female flowers are orange and take the form of a round inflorescence.
  • Fruit, which are between 1-4cm in diameter, are red to orange/yellow when mature and green when immature.

Paper mulberry can be confused with young native Flame tree (Brachychiton acerifolius), edible Fig fruit tree (Ficus carisa) and White mulberry (Morus alba).

If you think you have this plant, contact Rous County Council on 6623 3800.

Distribution map as at October 2016

Predictive mapping supplied by Queensland Biosecurity