Aquatic plants ›


General Infomation

The smallest flowering plant in the world. It appears as rootless, small green dots and may feel like grits when rubbed between fingers. Can completely cover shallow, slow-moving waterways.

Biological Control

Biological Control of Aquatic Weeds with Triploid Grass Carp

Small fish at very high stocking rates (see filamentous algae above) may give control; larger fish at normal stocking rates usually are not effective.


Chemical Control

Herbicide, Formulation and Mode of Action Code
Amount of Formulation
Active Ingredient Rate or Concentration
Herbicide, Formulation and Mode of Action Code

flumioxazin (Clipper) 51% MOA 14

Amount of Formulation

6 to 12 oz/A

Active Ingredient Rate or Concentration

3 to 6 ai/A or 100 to 400 ppb

Precaution and Remarks

Early morning applications may be more effective. If vegetation is dense, treat in sections to avoid reducing dissolved oxgen. Water pH greater than 7.5 will reduce effectiveness. A follow-up application may be needed for watermeal control.

Herbicide, Formulation and Mode of Action Code

fluridone (Sonar) 4 AS MOA 12

Amount of Formulation

Ponds: 0.16 to 1.5 qt/acre

Active Ingredient Rate or Concentration

0.16 to 1 lb/acre 10 to 90 ppb

Precaution and Remarks

Use the maximum labelled rate for the average depth of your pond. Do not apply when there is substantial outflow from the pond. Do not apply as a spot treatment. See label for specific weeds controlled. For watermeal, use 45 to 90 ppb. Other floating species may be controlled with lower rates. Do not use treated water for irrigation for 7 to 30 days. See label for irrigation precautions. Warning: 30 days may be insufficient restriction if pond water will be used to irrigate very sensitive crops, such as tobacco, tomatoes, or peppers.


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Species Data


Often found growing with duckweed in slow-moving water. It overwinters on the bottom of water bodies.

Similar Species

Similar in shape and color to the duckweeds (Spirodela and Wolffia), however, watermeal does not have any discernable roots.

Aquatic Plants App

Whether you're a professional botanist or a casual nature enthusiast, the NC State University (NCSU) Aquatic Weeds app has detailed information on a wide variety of aquatic weeds to assist in identification.