August is Invasive Plant Pest and Disease Awareness Month. During the month, we’re identifying some of the invasive species found in North Carolina, highlighting the department’s efforts to combat them and offering tips on how you can help reduce invasive-species populations in your area.
Hydrilla is capable of infesting freshwater lakes to depths of 20-25 feet and can block out native aquatic vegetation. The plant creates dense mats near the water surface, which can clog recreational motor boats and collect in industrial turbines.
The noxious weed originally appeared in Florida during the late 1950s, and was used in aquariums. It is believed that hydrilla spread as aquarium owners dumped their tanks into open bodies of water. By the 1970s, hydrilla was established throughout Florida.
The plant has spread from Florida as far north as Connecticut and as far west as California. In North Carolina, populations have been contained to just a handful of lakes. At Lake Gaston, which is densely populated with hyrdilla, the plant is managed by a technical committee for the benefit of property owners along the lake’s shores.
In 2009, hydrilla was reported in the Albemarle Sound for the first time. While the plant thrives in freshwater, it can survive in some levels of brackish water. And, now that hydrilla has entered the sound, it could easily spread to other parts of the estuary.
In response, employees at the NCDA&CS Plant Industry Division, N.C. State University and N.C. Department of Environment and Natural Resources organized a symposium in December 2010 to bolster awareness, discuss impacts and encourage management of hydrilla populations in the eastern part of the state. NCDA&CS weed specialist Rick Iverson was at that meeting, and saw the need to be proactive.
“In the area around the Albemarle Sound we have some pristine lakes, like Lake Phelps,” Iverson said. “It would be a travesty to allow hydrilla to establish in those lakes because it would quickly impair the unique character of North Carolina’s pocosin lakes.”
Under Iverson’s guidance, the department has begun a survey of all the public boat ramps in North Carolina. During the first phase of the program, specialists will survey more than 200 public boat ramps managed by the Wildlife Resources Commission. In the future, the program will expand to include all boat ramps in the state.
We recently tagged along with NCDA&CS field specialist Mike Massey as he surveyed a boat ramp at Lake Wheeler. Massey, along with 19 other field specialists, will be visiting boat ramps between now and September during hydrilla’s active growing season to take samples. For the survey, Massey used a unique device created by department employees specifically for sampling hydrilla and other species of submersed aquatic plant. Galvanized nails line the sides of the tool and attach to hydrilla as the rake-like device is pulled out of a body of water.
In the video below, you can learn more about the boat ramp project and watch Mike Massey survey Lake Wheeler in Raleigh.
As Iverson mentions in the video, the most important thing you can do to prevent the spread of hydrilla is clean your boat and trailer immediately after you leave a body of water. Transporting plant fragments in boats and trailers is the primary way invasive aquatic plants can be spread to new bodies of water.
For more information about hydrilla, check out these resources: