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Hygro, Miramar Weed, or East Indian Hygrophila

Hygrophila polysperma

Non-Native

Hygrophilia Location in the US
Hygrophilia Location in the Souteast US
Hygrophilia leaves up close

Hygrophilia drawing
Hygro enmass with Wild Rice
Hygro enmass with Wild Rice
Hygro submersed
Hygro submersed

Hygro submersed 2
Hygro submersed3
Hygrophilia flower

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 Hygro, Miramar Weed, or East Indian Hygrophila?

Physical Characteristics

Leaves:

  • Sword-shaped
  • Simple
  • 2-5 inches long
  • 0.2-1 inches wide

Flowers:

  • Immobile
  • Clustered at axils
  • Straight bracts
  • 5 sepals, sword-shaped, about 0.196 inches long
  • White along the edges
  • Covered with long, soft hairs
  • Yellow petals
  • Upper lip has 2 teeth about 0.098 inches long
  • Lower lip is 3-lobed
  • 4 stamen

Fruit:

  • Long and thin
  • 0.31-0.5 inches long
  • Holds 16 to 18 seeds
  • Smooth
  • Hairless

Stem:

  • Rectangular
  • Branching

Hygrophila can be confused with the native water primrose (submerged type), but water primrose does not have the fingerlike projections at the base of the leaves nor the squarish stem. Hygrophila can be completely submerged or stand above the water like an emergent plant.

Where Does it Grow?

Non-Native

Hygrophila is a perennial plant. It is native to India and Malaysia and was probably brought to the U.S. for the aquarium industry.

Hygrophila can be found in marshy areas along streams, swamps, or on shores of ponds where its horizontal roots form colonies.

Is it Invasive?

Hygrophila is considered a noxious pest because it grows so rapidly, out competing and eliminating native species.

This plant is not native to North America and should not be introduced into new water bodies and should be treated with herbicide when present.

How to Manage This Plant
Plant Glossary

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Photo Credits: The majority of the aquatic plant line drawings are the copyright of the University of Florida Center for Aquatic Plants (Gainsville). They are used with permission.

Aquatic plant photographs were provided by David Bayne, Jim Davis, Kelly Duffie, Billy Higginbotham, Michael Masser, John Clayton, Chetta Owens, Diane Smith, Joe Snow, Don Steinbach, Bridget Robinson Lassiter and Peter Woods.

You may use these photos, so long as you give credit to AquaPlant.

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