Limnobium spongia

Common Name(s): Frog's bit, American spongeplant

Native to Florida

Video ID segment (2-3 minutes / transcript below)

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For brief control information, see Efficacy of Herbicide Active Ingredients Against Aquatic Weeds by K. Langeland, M. Netherland, and W. Haller.

Video Transcript

Frog’s-bit, American spongeplant – Limnobium spongia
Frog’s-bit is a native plant that can be floating or rooted. It occurs in many water types throughout Florida. It can form dense mats that crowd out almost all other plants. Frog’s-bit leaves are very thick and leathery. They are either rounded or, in younger leaves, somewhat heart-shaped. The younger leaves tend to be bright and shiny above and reddish underneath, with rounded lobes. Undersides of young leaves have a central disk of red spongy cells. The leaf stalks have ridges on either side and are firm. In field situations, frog’s-bit can be confused with water hyacinth, Eichhornia crassipes. The best way to tell the difference between the two is to look at the roots and stems. Frog’s-bit has whitish roots. Water hyacinth has dark roots. Frog’s-bit has a slender, ridged leaf stalk. Water hyacinth has fleshy stems that are sometimes bulbous.

    Remember, frog’s-bit

  • has ridged leaf stalks.
  • Undersides of young leaves have a central disk of red spongy cells.
  • Frog’s-bit can be confused with water hyacinth.

Limnobium spongia blooms from summer to fall. Limnobium spongia is the only Limnobium species known to occur in Florida (Wunderlin, 2014). Frog’s bit is located in the southeastern U.S., as well as a few states in the north. In addition to water hyacinth, it is can also be confused with European frog-bit.