Skip to main content
Variable water-milfoil 

Variable water-milfoil 

Variable water-milfoil 
(Myriophyllum heterophyllum)

Description:  Variable water-milfoil is an underwater, plant with branching stems rising out from above the surface with compact, spreading roots.

Habitat:  Variable water-milfoil is an extremely well adapted plant, able to thrive in a wide variety of environmental conditions. It grows well in still and flowing waters, and can survive under ice. Variable water-milfoil grows rooted in water depths from 1 to 5 meters on various bottom types including biological muck, silt, sand and gravel.

Annual Cycle:  Variable water-milfoil is an extremely rugged watery perennial that grows through root division, broken pieces, young shoots, and seeds. Flowering spikes typically rise from the water in mid to late summer, but not all colonies produce flowers.  Self-shattering may occur during the growing season with stem sections developing roots even before they separate from the parent plant. Toward the end of the growing season some plants break apart and die back to their rootstalks; others overwinter intact. New growth sprouts from young shoots, roots, overwintering plants and plant debris as the water begins to warm in the spring, growing rapidly toward the surface. Certain milfoils are able to interbreed with other, closely related, milfoil species.

Origin and U.S. Range:  Variable water-milfoil is native to parts of the United States, but not native to New England. Variable water-milfoil is present in the Songo River at Sebago Lake State Park in Maine and all New England states except Vermont. A hybrid of this species (M. heterophyllum x M. laxum), has also been confirmed in Maine.

Look A likes:  May be confused with bladderworts, hornworts, mermaid weeds, water crowfoots, and other leafy water-milfoils.

Share this: