Mexican bean tree

Alert

Have you seen Mexican bean tree?

Be on the lookout for Mexican bean tree and report it to Biosecurity Queensland. Early detection and reporting are the key elements in controlling Mexican bean tree.

Call us on 13 25 23.

Native to tropical America, Mexican bean trees are among the most abundant weed species across large parts of Central America. These fast-maturing trees are quick to colonise open, disturbed sites or cyclone-damaged forests. They can cause serious and irreversible damage to native ecosystems.

An unknown number of Cecropia specimens were given away or sold by a private plant collector, possibly the original importer, near Mission Beach, north Queensland.

Mexican bean tree is a restricted invasive plant under the Biosecurity Act 2014.

Scientific name

Cecropia pachystachya, C. palmata and C. peltata

Similar species

  • Snakewood, pumpwood, trumpet tree, wild pawpaw, tree of sandpaper

Description

  • Fast-growing tree 10-20m tall, sometimes up to 25m tall.
  • Leaves are alternate, 10-50cm wide, resemble paw-paw leaves.
  • Lower leaf surface is densely covered with white hairs.
  • Leafstalks are usually 23-30cm long.
  • Hollow stems, flowers and fruits are key features.
  • Yellow flowers are arranged in clusters of spikes, 12-18cm.
  • Fruit is cylindrical, ovoid to oblong-ovoid, somewhat flattened, 3.3-3.7mm long, with soft, sweet flesh around many small seeds.

Habitat

  • Naturalised specimens are most likely to be found in wetter habitats such as riparian zones and dry rainforest remnants.

Distribution in Queensland

  • Garden specimens found in Mackay, Cairns,Brisbane and the Gold Coast.

Life cycle

  • Matures in 3-5 years.
  • Recorded to flower as early as 3.3 years of age.
  • Flowers are wind-pollinated and produce about 18% viable seeds.

Impacts

Environmental

  • Potential to invade and dominate moderately moist forest ecosystems in north Queensland, possibly causing serious and irreversible damage.

How it is spread

  • Seeds spread by fruit bats and birds.

Control

Herbicide control

  • Permit no. PER11463 allows triclopyr 240g/L + picloram 120g/L to be applied using basal bark or cut-stump method, and glyphosate 1:1 to water to be applied using frill or stem injection method.
  • Basal barking or cut-stumping with access in diesel at 1:60. If felling tree for cut-stumping, take care that trunk and stems in contact with ground do not coppice and give rise to new plants.
  • Vigilant Herbicide Gell (Active: 43g/kg Picloram as potassium salt) and cut-stump is also effective.

Legal requirements

  • Mexican bean tree is a restricted invasive plant under the Biosecurity Act 2014. All other Mexican bean tree species are prohibited invasive plants
  • It must not be given away, sold, or released into the environment without a permit.
  • All sightings of Mexican bean trees must be reported to Biosecurity Queensland within 24 hours of the sighting.
  • The Act requires everyone to take all reasonable and practical steps to minimise the risks associated with invasive plants and animals under their control. This is called a general biosecurity obligation (GBO).
  • At a local level, each local government must have a biosecurity plan that covers invasive plants and animals in its area. This plan may include actions to be taken on certain species. Some of these actions may be required under local laws. Contact your local government for more information.

More information