Salvinia molesta, Giant Salvinia

Invasive Species December 16, 2015 Print Friendly and PDF

Invasive Species: Salvinia molesta, Giant Salvinia

Giant salvinia is an aquatic fern with floating leaves that are 0.5 to 1.5 in. (2.5 to 3.8 cm) long and oblong and vary in color from green to gold to brown. The surfaces of the leaves have rows of arching hairs that look like little eggbeaters. When the plant is young, leaves are smaller and lie flat on the surface of the water. After maturing, giant salvinia forms chains of leaves that run together to form thick mats on the surface of the water. These mats restrict oxygen and light availability, causing death of the primary producers and disrupting the aquatic food chain. Submerged fronds are "stringy" and resemble roots. Plants reproduce by spores and by budding of broken stems or attached nodes. Giant salvinia is on the Federal Noxious Weed list and can invade most types of aquatic systems. The plant is native to South America and was introduced in North America as an ornamental plant.

What are invasive species, and why should we be concerned about them? 


Taxonomy: Scientific and Common Names for This Species

Hydropteridales > Salviniaceae > Salvinia molesta D. S. Mitchell

Synonym(s): kariba weed, salvinia, water fern, aquarium watermoss

Salvinia molesta - USDA PLANTS Profile

Distribution Maps

giant salvinia - The reported distribution of this invasive species across the United States (Source: Invasive Plant Atlas of the United States)

Up-to-the-minute distribution maps and why they are important 

Reporting This Invasive Species

What is the best way to report the occurrence of an invasive species? 

 How to report an invasive species sighting to EDDMapS - Early Detection & Distribution Mapping System

EDDMapS - Report an invasive species to EDDMapS.

County Extension Offices - Find your county Extension office on this map provided by USDA.

How to Identify

This invasive species can be identified by looking for the characteristics described in the paragraphs that follow.

Plant

Giant salvinia is an aquatic fern with floating leaves that are 0.5 to 1.5 in. (2.5 to 3.8 cm) long and oblong. When the plant is young, leaves are smaller and lie flat on the surface of the water.

giant salvinia (Salvinia molesta) giant salvinia (Salvinia molesta)
Scott Robinson, Georgia Department of Natural Resources, bugwood.org Mic Julien, Commonwealth Scientific and Industrial Research Organization, bugwood.org

Foliage

After maturing, giant salvinia forms chains of leaves that run together to form thick mats on the surface of the water and vary in color from green to gold to brown

giant salvinia
giant salvinia (Salvinia molesta)
giant salvinia
Scott Robinson, Georgia Department of Natural Resources, bugwood.org Scott Bauer, USDA Agricultural Research Service, bugwood.org

Foliage

The surfaces of the leaves have rows of arching hairs that look like little eggbeaters.

giant salvinia (Salvinia molesta)

giant salvinia (Salvinia molesta)
Troy Evans, Great Smoky Mountains National Park, bugwood.org Barry Rice, sarracenia.com, bugwood.org

Plants

Plants reproduce by spores and by budding of broken stems or attached nodes.

giant salvinia (Salvinia molesta) giant salvinia
Victor Ramey, University of Florida, bugwood.org Barry Rice, sarracenia.com, bugwood.org

Native species That Resemble Giant Salvinia

Azolla caroliniana, Carolina mosquitofern - Images at invasive.org

Carolina mosquitofern Carolina mosquitofern (Azolla caroliniana) Willd

Graves Lovell, Alabama Department of Conservation and Natural Resources, bugwood.org

Graves Lovell, Alabama Department of Conservation and Natural Resources, bugwood.org

Marsilea villosa, villous waterclover - Images at invasive.org

villous waterclover (Marsilea villosa) villous waterclover
Forest & Kim Starr, Starr Environmental, bugwood.org Forest & Kim Starr, Starr Environmental, bugwood.org

Additional Images for Giant Salvinia

Salvinia molesta images

Learning Resources for Giant Salvinia

Recognition Card - University of Florida, Institute of Food and Agricultural Sciences (IFAS) Extension

Field Notes: Biocontrol of Giant Salvinia: Video - Texas Parks and Wildlife

Fighting Invasives: Video - Texas Parks and Wildlife

Additional Information, Biology, Control and Management Resources

Control and management recommendations vary according to individual circumstances. Location, habitat, weather, and a variety of other conditions are factors that help determine the best treatment choice. To find the safest and most effective treatment for your situation, consult your state's land-grant institution. If you will use chemicals as part of the control process, always refer to the product label.

United States Land Grant University System - Find your Land Grant University's College of Agriculture, University Cooperative Extension Service, or other related partner on this map provided by USDA.

Pest Alert - USDA APHIS PPQ

Plant Invaders of Mid-Atlantic Natural Areas - National Park Service and U.S. Fish and Wildlife Service

Biological Control of Invasive Plants in the Eastern United States - USDA Forest Service

Domestic Programs Pest Evaluation - USDA Animal and Plant Health Inspection Services (APHIS) Plant Protection and Quarantine (PPQ)

Invasive Plant Atlas of New England - University of Connecticut

Federal Noxious Weed Disseminules of the United States - USDA APHIS

Global Invasive Species Database - Invasive Species Specialist Group

Center for Invasive and Aquatic Plants - University of Florida IFAS Extension

Invasives Database - TexasInvasives.org


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This work is supported by the USDA National Institute of Food and Agriculture, New Technologies for Ag Extension project.