Pistia stratiotes (Water Lettuce)

Pistia stratiotes (Water Lettuce) is a free-floating, aquatic perennial forming small rosettes, 4-6 in. across (10-15 cm) of velvety, soft green, deeply veined leaves. Resembling floating heads of lettuce, the leaves produce plantlets that stretch out from the mother plant on slender stems. Inconspicuous white flowers grow in the leaf axils. Feathery roots dangle from the plants, providing a hiding place for small fish. Water Lettuce notoriously multiplies and can rapidly cover vast expanses of open water. If it covers the surface of the water, then oxygen depletion and fish kills can occur. It will also eliminate submerged plants by blocking sunlight penetration. This plant should be controlled before it covers the entire surface of the pond. Native to tropical and subtropical areas, Water Lettuce occurs naturally in still waters of ponds, ditches, swamps, slow-moving streams. Highly susceptible to frost, Water Lettuce is a popular addition to water gardens and ponds, where it provides attractive foliage cover and discourages algae growth.

• This evergreen aquatic perennial grows up to 3-6 in. tall (7-15 cm) and 12-18 in. wide (30-45 cm).
• Performs best in full sun to part shade. No planting is necessary, simply place this floating plant directly on the surface of the water.
• Virtually pest and disease free.
• Reduce its spread by removing portions with a net.
• Native to tropical and subtropical lakes.
• Pistia stratiotes can be quite invasive in frost-free tropical climates where it forms extensive mats that can block navigational channels, impede water flow in irrigation and flood control canals, and disrupt submersed animal and plant communities. In the U.S., it is included on the Federal Noxious Weed List.
• Find where this species is invasive in the U.S.