THE ISSUE:  Water hyacinth 

Water hyacinth (Eichornia crassipes) is a free-floating freshwater perennial that is native to South America.  It was introduced into the U.S. as an ornamental, but then escaped. It can form thick masses of vegetation that float on the surface of slow-moving bodies of water. Its presence can change aquatic habitat, remove available oxygen, and slow the flow of water. It has significant negative impacts on agriculture, recreation, and the environment.

Water hyacinth is well known for its purple showy flowers, and its ability to double in size every 4-10 days. It can grow 1.5 to 3 feet tall. Leaves are broad, round, glossy, up to 12 inches long, and 6 inches wide. Dark colored roots have a feathery appearance and hang below the plant in the water. Roots can be up to 3 feet long. It can reproduce from seed and asexually as stolons and daughter plants break off and float away. 

Integrated Pest Management (IPM) Options: 

• Prevention— Learn to identify this plant.  Never transport unknown plant material. Always clean recreational equipment before transporting! Never dispose of aquarium contents in bodies of water. 

• Mechanical—Extreme care must be taken to remove all plant parts from the water. Mechanical removal in conjunction with other control methods can be effective. It is best to identify infestations early when plants can be removed carefully by hand.  

• Chemical—Herbicide applications in conjunction with other control measures may be necessary. Report any sightings of water hyacinth to local authorities, who can help prescribe herbicide applications. Always read and follow herbicide
label directions!

Justin Hatch, University of Idaho Extension Agriculture Educator in Caribou and Bear Lake Counties. 208-547-3205 [email protected]