Stem

  • Aquatic weed up to 12 ft. long, submersed, branched near water surface, growing points often reddish; breaks into fragments easily
Photo of eurasian watermilfoil plant
 

Leaves

  • Whorled with 4 leaves per node; leaves are green to brown, less than 1.25 in. long and pinnately-divided with more than 14 pairs of narrow, opposite lobes, less than 0.4 in. long   
Photo of eurasian watermilfoil plant
 

Flower

  • Pinkish and small, each with a small, bract-like leaf 
  • Occur in clusters on small, pencil-like stalks that emerge from water, 1-3 in. long; stem often bends to become parallel with the water surface after flowering
Photo of eurasian watermilfoil plant
 

Root

  • Creeping rhizomes
Photo of eurasian watermilfoil plant
 

Other

  • Most common in still or slow-moving water but can sometimes be found in fast-moving rivers, streams and irrigation ditches; known to occur in Carson City, Douglas and Washoe counties
  • Perennial; reproduces by rhizomes, stem fragments and seed
 

Control

  • Mechanical removal can be effective but must be done repeatedly; escaped stem fragments can form new plants; draining then allowing an empty water-body to freeze can be effective
  • Aquatic herbicides such as 2,4-D, copper complexes, diquat, endothall, fluridone, and triclopyr are effective; large infestations should be treated a portion at a time to prevent low oxygen levels as plants decompose
Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Nevada Noxious Weed Field Guide – Eurasian watermilfoil, Extension, University of Nevada, Reno, Field Guide

Learn more about the author(s)

 

Also of Interest:

 
Photo of curlyleaf pondweed plant
Nevada Noxious Weed Field Guide – Curlyleaf pondweed
Curlyleaf pondweed is a noxious weed that has been identified by the state of Nevada to be harmful to agriculture, the general public, or the environment. Learn more about this weed.
Blecker, L., Creech, E., Dick, J., Gephart, S., Hefner, M., Kratsch, H., Moe, A., Schultz, B. 2020, Extension, University of Nevada, Reno, Field Guide
 

Associated Programs

placeholder image - 0

Master Gardeners of Douglas County

Learn about the Master Gardener program in Douglas County, Nevada.

Master Gardeners at tabling event

Master Gardeners of Nevada

Program trains local gardeners to provide research-based horticulture information to Nevadans

Weed Warriors Invasive Weed Training cb

Weed Warriors Invasive Weed Training

The Weed Warriors program tackles the growing problem of weeds on public and private land.