Hairy senna

Native to tropical America, hairy senna is a perennial flowering shrub. It invades disturbed areas such as roadsides, fence lines, creekbanks, grazed pastures and the edges of rainforest.

Hairy senna is a restricted invasive plant under the Biosecurity Act 2014.

Scientific name

Senna hirsuta

Other names

Shower senna, slimpod glaberrima senna, stinking cassia, woolly senna

Similar species

Description

  • Perennial shrub up to 3m tall.
  • Single or multi-stemmed, becomes woody with age.
  • Leaves are pinnate with 2-6 pairs of hairy leaflets 4-9cm long.
  • Leaf stalks are ribbed with prominent conical gland at base.
  • Flowers are yellow and clustered in groups of 5-8 on upper branches.
  • Pods are hairy, cylindrical, 10-14cm long, each containing 50-90 round dull seeds.

Habitat

  • Occurs along roadsides, in disturbed areas, pastures, waterways and waste areas.

Distribution in Queensland

  • Found along northern and central Queensland coast.

Life cycle

  • Reproduces by seed only.
  • Flowering occurs during autumn and early winter.

Impacts

Environmental

  • Invades disturbed areas such as roadsides, fence lines, creekbanks, grazed pastures and rainforest edges.

How it is spread

  • Seeds can spread by water, animals, footwear, machinery and vehicles.

Control

Physical control

  • Hand-pull seedlings and small plants when soil is wet, making sure that all roots and stem fragments are removed.

Herbicide control

  • If plants are cut down, immediately treat stump with suitable herbicide, otherwise shrub will reshoot.
  • There is no herbicide currently registered for control of hairy senna in Queensland; however, an off-label use permit (Permit No. PER11463) allows use of various herbicides for control of environmental weeds in non-agricultural areas, bushland, forests, wetlands, and coastal and adjacent areas. Visit the Australian Pesticides and Veterinary Medicines Authority website for more information.

See the Hairy senna fact sheet (PDF, 422KB) for herbicide control and application rates.

Biological control

  • No known biological control agents.

Legal requirements

  • Hairy senna is a restricted invasive plant under the Biosecurity Act 2014.
  • It must not be given away, sold, or released into the environment without a permit.
  • 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