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Giant Salvinia

Scientific Name

Salvinia molesta D. S. Mitch. (ITIS)

Common Name

Giant salvinia, kariba-weed

Native To
Date of U.S. Introduction
Means of Introduction

Horticultural trade (McFarland et al. 2004)


Forms dense mats that block sunlight and reduce oxygen levels (McFarland et al. 2004)

Giant salvinia
Image use policy

Giant salvinia, plants


Photo by Scott Bauer; USDA, Agricultural Research Service

Find more images


  • Fungus Fights Oxygen-Sucking Water Weed

    • Aug 12, 2019
    • USDA. ARS. Tellus.

    • In parts of the South, there are stories about an invasive floating weed, which forms such a dense mass that it enables small animals to walk across water. This weed, called giant salvinia, is an exotic fern from South America that invades ponds, lakes, and other waterways in the United States. It damages aquatic ecosystems by outgrowing and replacing native plants that provide food and habitat for native animals and waterfowl.

      Agricultural Research Service (ARS) scientists are testing a naturally occurring fungus (Myrothecium spp.) against giant salvinia to help control it. Initial tests have found that the fungus stops this problematic weed from growing and even can kill it.

Distribution / Maps / Survey Status

Federally Regulated

  • Noxious Weeds Program

    • USDA. APHIS. Plant Protection and Quarantine.

    • Includes species listed as a Federal Noxious Weed under the Plant Protection Act, which makes it illegal in the U.S. to import or transport between States without a permit.


Selected Resources

The section below contains highly relevant resources for this species, organized by source.

Federal Government
International Government
State and Local Government