Cutleaf Watermilfoil

Myriophyllum pinnatum

Illustration: USDA-NRCS PLANTS Database / Britton, N.L., and A. Brown. 1913. An illustrated flora of the northern United States, Canada and the British Possessions. 3 vols. Charles Scribner’s Sons, New York. Vol. 2: 616.

What is Cutleaf Watermilfoil?

Physical Characteristics

Leaves:

• Whorls of 3
• Up to 1.18 inches long

Emergent Leaves:

• Linear to oval-shaped
• Serrated
• Up to 0.79 inches

Flowers:

• Above water
• Bracts triangular
• Bracts about 0.04 inches long

Petals:

• Purplish in color
• 0.59-0.79 inches long
• Rounded at ends

Fruit:

• Pale colored
• Oval-shaped
• 0.05-0.07 inches long
• Flat sides

Stem:

• Rooted in mud
• Branching
• Elongated when submersed

Where Does it Grow?

USDA, NRCS. 2018. The PLANTS Database (http://plants.usda.gov). National Plant Data Team, Greensboro, NC 27401-4901 USA.

Cutleaf watermilfoil can be found in swamps, muddy areas or in shallow waters.

Pros and Cons of Cutleaf Watermilfoil

Submerged portions of all aquatic plants provide habitats for many micro and macro invertebrates. These invertebrates in turn are used as food by fish and other wildlife species (e.g. amphibians, reptiles, ducks, etc.). After aquatic plants die, their decomposition by bacteria and fungi provides food (called “detritus”) for many aquatic invertebrates.