A Diagnostics Tool for Pond Plants and Algae

Asian Marshweed

Limnophila sessiliflora

Non-Native

USDA, NRCS. 2018. The PLANTS Database (http://plants.usda.gov, 28 March 2018). National Plant Data Team, Greensboro, NC 27401-4901 USA.
Illustration courtesy of University of Florida/IFAS Center for Aquatic and Invasive Plants. Used with permission.

What is Asian Marshweed?

Physical Characteristics

Leaves:

  • Arranged in whorls around stem
  • 0.17 – 0.5 inches long

Emerged:

  • Dark green
  • Sword-shaped
  • Whorls of 5-8
  • Edges serrated

Submerged:

Flowers:

  • Small
  • Stalkless
  • Single flowers
  • Located on top of plant
  • Above water
  • Petals 0.2-0.39 inches long
  • Blue, lavender, pink, or violet
  • Upper lip white or pink with 2 blue dots
  • 3 oval lobes
  • 0.16 – 0.28 inches long
  • Hairy

Fruit:

  • Dry seed pod
  • Elliptical shaped
  • 0.14 – 0.22 inches long
  • Green-brown in color under water
  • Dark brown in color above water

Stem:

  • Up to 12 feet long
  • Many inches above water and upright

Roots:

Where Does it Grow?

Non-Native

Asian marshweed is native to India, Ceylon, and the Philippines.

Is it Invasive?

Asian marshweed is non-native to North America and it can be an aggressive invader of ponds and other bodies of water. If colonies cover the surface of the water, then oxygen depletion and fish kills can occur. These plants should be controlled before they cover the entire surface of the pond.

This is a non-native plant that should not be grown as it is invasive and illegal to possess or transport this species in Texas. Please report sightings to the Texas Parks and Wildlife Department at (512) 389-4800.

How to Manage This Plant
Plant Glossary