Hydrilla is an invasive non-native weed that originates in South America. It has broad leaves that form a whorl from the central stem. It can grow up onto shore, although it prefers the water. Hydrilla can grow quickly and can become so dense on the water’s surface that people and animals can actually walk across it!
The most effective way to control hydrilla is to use multiple aggressive treatments with a variety of herbicides and algaecides. A mix of Tsunami DQ and Crystal Plex at a 1:2 ratio tends to have a good effect on hydrilla growth. This means that if you use 2 gallons of Tsunami DQ, you would use 4 gallons of Crystal Plex and mix with 15 to 20 gallons of water to complete the solution. Other mixes include using combinations of Tsunami DQ and Aquathol K, Tsunami DQ and Hydrothol, Aquathol K and Crystal Plex, and Hydrothol and Crystal Plex.
When treating hydrilla, variety is the spice of success. Mixing and matching herbicides and algaecides appears to create the most success in controlling hydrilla.
Check out our other blogs within our Weed ID Series: