Water Lettuce

Water Lettuce

(Pistia stratiotes)
*Detected in Michigan*
WATCH LIST

This species is currently allowable for sale and possession in Michigan. If these plants are observed outside of cultivation, please report to:

DEQ Aquatic Invasive Species Program DEQ-WRD-ANC@michigan.gov 517-284-5593

If possible, please take one or more photos of the invasive species you are reporting. Also make note of the location, date and time of the observation. This will aid in verification of your report. You may be asked to provide your name and contact information if follow-up is needed.

- Or - use the Midwest Invasive Species Information Network (MISIN) online reporting tool 

- Or - download the MISIN smartphone app and report from your phone - http://www.misin.msu.edu/tools/apps/#home

Identification:

  • Free-floating – forms a rosette of leaves that resembles an open head of lettuce
  • Leaves are thick, ridged, rounded at the end, light green, and have short, white hairs
  • Produces small, white to pale green flowers
  • Many feathery roots dangle under the rosette

water lettuce
Troy Evans, Great Smoky Mountains National Park, Bugwood.org

water lettuce
Karen Brown, University of Florida, Bugwood.org

water lettuce invasion
USDA APHIS PPQ - Oxford, North Carolina, USDA APHIS PPQ, Bugwood.org

Habitat: Water lettuce can be found in ponds, lakes, rivers, and streams.

Native Range: Uncertain – likely tropical or subtropical

U.S. Distribution: Water lettuce has been introduced to the south and western United States, as well as Ohio, New York, New Jersey, Maryland, Delaware and Michigan.

Local Concern: This freshwater perennial creates thick mats that reduce oxygen levels, block sunlight, and prevent growth of submerged vegetation. Mats interfere with recreation and can have a negative effect on fish and other aquatic species in an infested area.

MORE INFORMATION:

Water Lettuce Invasive Species Alert - Printable PDF