Eurasian Watermilfoil
(Myriophyllum spicatum)

Photo from Montana's Noxious Weeds, revised ed.
by Monica Pokorny & Roger Sheley.

Used with permission from
Montana State University Extension.

Growth Habit: submerged herbaceous perennial herb native to Europe, Asia, and northern Africa. Accidentally introduced to the United States in the late 1800's.

Leaves: Three to four bright green leaves are whorled around the stem at each joint. Each leaf is 1.2 inches in length and has 12 to 48 thread - like divisions. Leaves rarely extend above the water surface.

Stem: Stems can be 10 feet or more in length and 0.1 inches thick.

Flower: A rigid pink flowering spike, from 2 to 8 inches long, is held erect above the water surface from June to August. Small yellow four-petaled flowers are arranged in clusters on the flowering spike.

Roots: Eurasian Water Milfoil has numerous roots at the base of the plant and along the stem.

Seeds: Hard, segmented capsule containing four seeds.

Reproduction: Asexual reproduction via sprouting plant fragments and rhizomes is the dominant means of spread.

Habitat: lakes, ponds, slow moving streams, reservoirs, estuaries and canals

Biological Control:

Herbicides: Sonar AS