Water mimosa

• Floating perennial weed that attaches to bank at water's edge and sends down taproot.
• Stems to 1.5m long, grow out over water and form spongy, fibrous covering between nodes.
• Leaves have leaflets, 8–20 pairs per pinna. Leaflets are very sensitive to touch and close quickly.
• Flowers are yellow, ball-shaped, 30–50 per spike and each flower is 7–16mm long, 0.5–1mm broad.
• Seeds are oval and brown, 4–8 per legume. Each seed is 4–5.1mm long, 2.7–3.5mm broad.
• On land, has smaller leaves and flowers, no spongy floating tissue.

• Grows on land in damp soil or on water as thick floating mats.
• Commonly found in and around freshwater pools, swamps and canals.

• Found in South East Queensland.

• Grows from seeds and stem sections that break free from parent plant.
• Flowering begins in early summer.

Environmental

• Restricts water flow in creeks, channels and drains.
• Increases water loss through evapotranspiration.
• Reduces water quality by preventing light penetration and reducing oxygenation of water.
• Creates favourable habitat for mosquitoes.
• Reduces fish activity.
• Kills native, submerged water plants and fish.
• Replaces native wetland plants.

Social

• Impedes recreational water sports and boating access.

• Has been subject to sale and distribution through Asian communities and gardeners.
• Floating rafts of dense inter-woven stems can be dislodged by water movement (especially during floods) and re-establish further downstream.

• Find out how farmers can prevent weed spread.
• Find out how gardeners and outdoor enthusiasts can prevent weed spread.

• Call 13 25 23 if you find a plant you suspect may be water mimosa to seek advice on control options

Biological control

• No known biological control agents.

• Water mimosa is a category 2, 3, 4 and 5 restricted invasive plant under the Biosecurity Act 2014.
• You must not keep, move, give away, sell, or release into the environment. Penalties may apply.
• All sightings of water mimosa must be reported to Biosecurity Queensland within 24 hours of the sighting.
• You must take all reasonable and practical measures to minimise the biosecurity risks associated with dealing with water mimosa under your 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 water mimosa. Some of these actions may be required under local laws. Contact your local council for more information.