Mimosa pigra, giant sensitive tree
Mimosa pigra, Fam. Mimosaceae
An erect many-branched spreading shrub to 6m, stems with rose-like thorns 5-10mm long. Young stems hairy.
| Weed Category: |
Restricted invasive plants Category 5 Plants declared invasive under the Biosecurity Act 2014, that are present in QLD.
Not to be kept.
 Thirty-two WONS (Weeds of National Significance) have been identified because of their impact on primary production and the environment, potential for spread and socioeconomic impacts.
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| Weed: | Yes |
| Form or habit: | Shrub |
| Family: | Mimosaceae |
| Leaf: | Compound Alternate Compound, alternate bipinnate fern-like, 200-250mm long, 6-16 pairs of pinnae with many pairs of tiny bright green leaflets, usually with marginal hairs; stalk and rachis prickly. Leaves sensitive, folding when touched and at night. |
| Flower conspicuous: | Conspicuous |
| Flower colour: |
Purple, Pink |
| Flower description: | Tiny, purplish to pink in fluffy globular heads, 10-20mm wide, borne in axillary pairs or singly. |
| Fruit conspicuous: | Conspicuous |
| Fruit colour: |
Green |
| Fruit: | Dry |
| Fruit description: | Pods olive green flat densely hairy with rusty bristles, 60-80 x 9-14mm, containing 14-26 seeds, and breaking up at maturity into one-seeded segments while leaving the outer frame behind. Seeds oblong, brown or green, 4-5 x 2mm. |
| Habitat: | |
| Distribution | |
| Food source for: | |
| Toxicity: | No toxicity known |
| Origin: | Tropical America |
| Notes: | Spread by: seeds retained in buoyant segments spread by water, contaminated soil and vehicles; segments adhere to ‘everything’. Seeds may pass through the gut of animals. Also spread by suckering. Invades/threats: wetlands, river banks, billabongs and spreading onto drier floodplains. Notes: introduced to the Darwin Botanic Gardens in the late 1800’s and only identified as a major problem in the 1950s. Forms dense impenetrable thickets that smother pastures and native habitat, impede access to water and provide habitat for feral pigs. The only known infestation in Queensland is at the Peter Faust Dam; where introduction is thought to be via boat trailers. An eradication program is in place. A fast growing and aggressive species; flowering begins as soon as 4 months after seed germination and a large plant may produce 220 000 seeds per year that may be viable for up to 20 years. Category 5 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). |
| Information sources: | Mackay Regional Pest Management Group (2018) Weeds of the Mackay Whitsunday Region Second Edition. |
