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Water mimosa
Pest alert
If you have seen this plant
Call QPIF 13 25 23
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- Water mimosa (Neptunia spp.)
Photo courtesy Bernard Loison
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- Water mimosa leaves and stem
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- Branching stems extending into water
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- Stems are covered with a spongy fibrous layer
General information
Water mimosa (Neptunia spp.) is a Class 1 declared pest plant in Queensland. Class 1 pests established in Queensland are subject to eradication from the state. Landowners must take reasonable steps to keep land free of Class 1 pests. It is a serious offence to introduce, keep, grow or supply a Class 1 pest without a permit issued by Queensland Primary Industries and Fisheries. Penalties of up to $80,000 apply.
Neptunia spp. are aquatic nitrogen fixing legumes. The release of nitrogen into water bodies can lead to increased algal blooms and increase the vigour of associated Class 2 pest plants such as water hyacinth, water lettuce and salvinia.
The release of nitrogen by Neptunia spp. into water bodies affects water quality and increases water treatment costs.
Overview
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Scientific name |
Neptunia oleracea and N. plena |
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Impacts |
- restricts water flow in creeks, channels and drains
- impedes recreational water sports and boating access
- increases water loss through evapotranspiration
- reduces water quality by preventing light penetration and reducing oxygenation of water
- creates a favourable habitat for mosquitoes
- reduces fish activity
- causes the death of native, submerged water plants and fish
- replaces native wetland plants
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Description |
- an aquatic-floating perennial weed
- stems grow out over the water and form a spongy-fibrous covering between the nodes
- yellow ball-shaped flowers appear in early summer
- olive-green leaves arranged in opposite pairs along the stem
- land form has smaller leaves and flowers, and has no spongy floating tissue
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Habitat and distribution |
- grows on land in damp soil or in water as thick floating mats
- commonly found in and around fresh water pools, swamps and canals
- found in South East Queensland
- Neptunia oleracea and Neptunia plena are native to Mexico, Costa Rica and to northern South America
- Neptunia plena grows in the coastal regions of southern North America, Central America, northern South America and tropical Asia
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Control |
- there are no chemicals registered for control
- mechanically remove the infestation by removing all plant matter from the infested water body and pulling plants out of the surrounding banks, ensuring to remove the attached root system
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Declaration details |
- a declared Class 1 plant under the Land Protection (Pest and Stock Route Management) Act 2002
- importation, possession and sale is prohibited
- landowners are required by law to keep their land free of this plant
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Further information |
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Page maintained by Sonia Jordan
Last updated 09 July 2009
