Amazon frogbit

Amazon frogbit is a declared Class C weed.

Another name for this plant is Limnobium laevigatum. It is also known as West Indian spongeplant, South American spongeplant and smooth frogbit.

Amazon frogbit


You should use this as a guide. There may be other plants or weeds that look similar.

If you are unsure, contact the Weed Management Branch.


These features describe the habit of this plant:

  • floating, perennial aquatic plant
  • up to 50cm tall
  • infestations can develop very quickly, forming dense mats across waterbodies and below shading plants.

Amazon frogbit - habit

Stems and branches

These features can identify the stems and branches:

  • floating rosettes that send runners out into the water, the end of which form juvenile plants
  • juvenile plants have an inflated stalk.

Amaon frogbit - stems and branches


These features identify the leaves:

  • smooth, round and fleshy
  • up to 4cm across
  • sponge-like sections on their undersides.

Amazon frogbit - leaves


These features can identify the flowers:

  • small, white and unisexual
  • about 1.3cm in diameter.

Amazon frogbit - flowers

Fruit and seeds

These features can identify the fruit and seeds:

  • fruit is a fleshy capsule 4 to 13mm long and 2–5 mm in diameter
  • seeds are 1mm long, ellipsoid, and hairy.

Amazon frogbit - reproduction


Amazon frogbit originates from fresh water habitats of tropical and subtropical central and South America.


Amazon frogbit can spread rapidly through quick seed production and vegetative growth. The small, floating seeds easily disperse via water and wind once produced.

Amazon frogbit has the potential to seriously degrade ecosystems if left untreated.


If you think you may have seen Amazon frogbit, or have this weed on your property, do not attempt to control it. Contact the Weed Management Branch immediately for assistance.

Last updated: 12 January 2018