Gymnocoronis spilanthoides

• forms floating mats, blocking irrigation ditches, shallow dams and waterways
• invades and degrades natural wetlands

• an aquatic perennial that grows over the water surface
• produces runners and floating stems up to 2.5 m long
• grows as a rounded bush
• shiny dark-green leaves are 5-20 cm long and grow in opposite pairs
• stems are hollow between the nodes, allowing the plant to float
• young stems are light green with dark-green blotches
• young round stems become six-sided as the plant grows
• flowers resemble white pompoms 15-20 mm in diameter
• seeds are yellow-brown and ribbed

• favours shallow and slow-moving water
• grows over water surface or in wet, marshy soils
• seeds germinate in spring and, if conditions are right, in summer
• becomes dormant when temperatures drop
• spreads by broken stem, leaf fragments and seed
• seeds spread by water, and in soil on vehicle tyres and animals' feet

• before attempting control, report weed to the Biosecurity Queensland (part of the Department of Employment, Economic Development and Innovation)
• remove mechanically
• place plant material in a sealed plastic bag, leave in sunlight to rot then burn or dispose of at a council-approved landfill tip
• do not leave broken plant pieces in the area
• apply herbicide
• see the senegal tea fact sheet for further information on control, including registered herbicide application rates

• 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

• local government office or Biosecurity Queensland, phone 13 25 23
• Senegal tea fact sheet (PDF, 190 kB)
• Publications
• Pest mapping
• Weedbuster - weed awareness program
• Land Protection (Pest and Stock Route Management) Act 2002
• Brisbane City Council weed identification
• Weeds to whack
• James Cook University North Queensland weeds