Not yet in Montana!

Hydrilla was introduced to the U.S. in the 1950’s as an aquarium plant. This water weed was first found in Florida but is now pervasive further west. Hydrilla has been detected as far north and west as the Columbia River in Washington state, although it has not yet made a home in Montana.

Potential Harms:

Hydrilla reproduces through fragmentation, a process where the plant breaks apart and starts growth as a new plant.  Because of this, hydrilla has the potential to take over a water body very quickly.  A main concern lies in its ability to clog irrigation canals and hydroelectric power plant intakes.  In South Carolina, hydrilla caused a powerhouse to shut down for seven weeks, causing $2,650,000 in damage.

In addition to these economic harms, hydrilla impacts recreational activities such as boating, swimming, and fishing as a result of the thick mats which grow on water surfaces.

Also, as with most water weeds, there are ecological concerns. Vast overtaking by hydrilla may alter the natural ecosystem choking out other native plants and affecting native fisheries.

Identification:

• Hydrilla’s leaves have sharp, serrated edges.
• The leaves are in whorls of 4 to 8 along the stem.
• Typically hydrilla leaves are a bright green, however with an abundance of sun the leaves may turn yellow or brown.
• The stems may grow to be as long as 25 feet.
• The plant thrives in versatile habitats: It can grow in just a few inches of water or in water over 20 feet.

Prevention:

Herbicides can help to temporarily control hydrilla populations.  Hydrilla has yet to make its way to Montana.  Therefore, prevention is particularly important. Inspecting, cleaning, and drying all fishing and boating equipment will best help to prevent the spread of this plant to new waters.

Links to more info on Hydrilla:

http://fwp.mt.gov/fishing/guide/ANS/plants.html#hydrilla

http://plants.ifas.ufl.edu/node/183