Giant Salvinia

Giant Salvinia: Salvinia molesta

Salvinia in someones hand — Image Credit: R. Helton, Texas Parks and Wildlife Department Design and Production: Texas Sea Grant College Program

Giant salvinia is an aquatic fern prohibited in the United States by Federal law.

Oblong floating leaves, 1/2 to 1 1/2 inches long. Young plants have smaller leaves that lie flat on the water surface. As plants mature and aggregate into mats, leaves are folded and compressed into upright chains.

Leaf surfaces have rows of cylindrical hairs topped with four branches that are joined at the tips to form a "cage" (view with hand lens). These hairs give a velvety appearance and repel water. Distinguish from common salvinia, Salvinia minima, which has leaf hairs with branches always free at the tips.

Underwater root-like structures conceal stalks with egg-shaped spore cases attached. Spore cases are not found on young plants.

Habitat:

Salvinia Close-up — Image Credit: R. Helton, Texas Parks and Wildlife Department Design and Production: Texas Sea Grant College Program

This South American native is currently invading waterbodies in the Southeastern U.S. and has the potential to rapidly invade and infest Florida’s ponds, lakes, and rivers. Its introduction into the U.S. is linked to the importation of aquarium plants as an accidental contaminant. It has caused severe economic and environmental problems in Texas and Louisiana and in many countries including New Zealand, Australia, and South Africa.

Help protect our aquatic resources, watch out for and immediately report giant salvinia infestations. If you have seen this plant in cultivation or in the wild, please contact the Florida Fish and Wildlife Conservation Commission at 850-617-9430.

Behavior:

Salvinia leaves — Image Credit: R. Helton, Texas Parks and Wildlife Department Design and Production: Texas Sea Grant College Program

Giant salvinia grows rapidly to cover the surface of lakes and streams, spreading aggressively by vegetative fragments. It forms floating mats that shade and crowd out important native plants. Thick mats reduce oxygen content and degrade water quality for fish and other aquatic organisms. Mats impede boating, fishing, and swimming and clog water intakes for irrigation and electrical generation.

Additional Information:

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Giant Salvinia (Salvinia molesta)