Myriophyllum sibiricum (Northern Water-milfoil)

Plant Info
Also known as: Common Water-milfoil, Shortspike Watermilfoil
Genus:Myriophyllum
Family:Haloragaceae (Water-milfoil)
Life cycle:perennial
Origin:native
Habitat:part shade, sun; shallow to 18 ft deep water; lakes, ponds, rivers
Bloom season:June - September
Plant height:1 to 5 feet
Wetland Indicator Status:GP: OBL MW: OBL NCNE: OBL
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

Pick an image for a larger view. See the glossary for icon descriptions.

Detailed Information

Flower: Flower shape: 4-petals Flower shape: indistinct Cluster type: spike

[photo of flowering spike] Spike up to 4 inches long at the top of the stem and branch tips, rising above the water's surface, with separate male and female flowers on the same plant (monoecious). Flowers are tiny, stalkless, and are whorled in 4s around the stem. Male flowers are at the tip of the spike, have 8 yellow stamens and lack petals or have 4 pinkish petals.

[close-up of flowers and bracts] Female flowers are below the males and have a 4-parted yellowish to deep pink style and no petals. At the base of a flower is a green bract, as long as or shorter than the flower, toothless or minutely toothed.

Leaves and stems: Leaf attachment: whorl Leaf type: compound

[photo of leaf whorl] Leaves are whorled all along the stem with usually 4 leaves in a whorl, occasionally 3 or 5, mostly broadly egg-shaped in outline, 1 to 5 cm (3/8 to 2 inches) long with 5 to 12 pairs of thread-like, toothless segments. The lowest leaflet pair is longest and spreading to ascending, the leaflets becoming shorter and more ascending as they ascend the central stalk. Leaves tend to retain their shape when removed from the water.

[photo of stem] Stems are yellowish to reddish becoming white when dry, smooth, unbranched or with a few forked branches. Colonies are formed from spreading rhizomes. Turions (winter buds) are stiff, dark, cylindric to club-shaped, and formed on side branches in autumn.

Fruit: Fruit type: seed without plume

[photo of fruit] Fruit is brown, 2 to 3 mm long, with 4 smooth lobes rounded or somewhat bumpy along the outer edge, and eventually splits into 4 seeds.

Notes:

Northern Water-milfoil is the most common Myriophyllum species in Minnesota, found in soft to hard lakes, ponds and slow-moving rivers with sandy or boggy bottoms, most often in less than 5 feet deep water.

With the exception of Myriophyllum tenellum, Myriophyllum species are recognized by leaves compound with a central stalk and multiple spreading, thread-like leaflets, usually whorled in 4s; separate male and female flowers on the same plant (monoecious); most with an emersed terminal spike of flowers and fruits. The overall form of Myriophyllum is like some other aquatic species, notably Ceratophyllum (Coontail), which has forked leaves that lack a central stalk and flowers are all in the leaf axils.

Northern Water-milfoil is distinguished by its floral bracts mostly shorter than the flowers and toothless or minutely toothed, and leaves mostly broadly egg-shaped in outline with 5 to 12 pairs of leaflets, the lowest leaflet pair longest and spreading. The leaves tend to retain their shape when removed from the water. Turions (winter buds) are produced in fall; they are stiff, dark, cylindric to club-shaped.

Most similar is Eurasian Water-milfoil (M. spicatum), which also has floral bracts shorter than the flower, but 12 to 21 pairs of leaflets per leaf that are more similar in size and ascending, the leaf usually more oval-elliptic in outline, and leaves are very limp and collapse when removed from the water; it also produces no turions. Whorled Water-milfoil (M. verticillatum) may have 12 or fewer pair of leaflets like Northern Water-milfoil, but its floral bracts are longer than the flowers and distinctly divided with comb-like linear lobes.

Please visit our sponsors

  • Minnesota Native Plant Society

Where to buy native seed and plants ↓

Map of native plant purveyors in the upper midwest

  • Natural Shore Technologies - Using science to improve land and water
  • Itasca Ladyslipper Farm - Native orchids, container grown
  • Prairie Restorations - Bringing people together with the land
  • Landscape Alternatives - Distinctive Native Plants since 1986!
  • Shop for native seeds and plants at PrairieMoon.com!

More photos

Photos by K. Chayka taken in Chisago County. Photos by Peter M. Dziuk taken in Aitkin, Anoka and Beltrami counties.

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Post a comment

Note: All comments are moderated before posting to keep the riff-raff out. An email address is required, but will not be posted—it will only be used for information exchange between the 2 of us (if needed) and will never be given to a 3rd party without your express permission.

For info on subjects other than plant identification (gardening, invasive species control, edible plants, etc.), please check the links and invasive species pages for additional resources.



(required)




Note: Comments or information about plants outside of Minnesota and neighboring states may not be posted because Id like to keep the focus of this web site centered on Minnesota. Thanks for your understanding.