What kind of hydrilla is in North Carolina?

North Carolina primarily battles the monoecious biotype of hydrilla. Unlike the Florida strain, this biotype is cold-tolerant and dies back to the sediment every winter.

Where is hydrilla found in NC?

Major infestations have occurred in Lake Gaston, Lake Norman, the Eno River, and numerous smaller ponds and reservoirs across the Piedmont and Coastal Plain.

Who manages hydrilla in North Carolina?

The NC Division of Water Resources coordinates the Weed Control Program, often cost-sharing herbicide treatments and grass carp stocking with local municipalities.

Back to State Distribution

Hydrilla in North Carolina: The Monoecious Migration

Examine the spread of the monoecious hydrilla biotype in North Carolina's reservoirs and rivers, and the state's aggressive response.

The Cold-Tolerant Threat

North Carolina represents a critical transition zone in the national Hydrilla verticillata invasion. While southern states battle the dioecious biotype (which grows year-round), North Carolina is the stronghold of the monoecious biotype.

This strain is highly cold-tolerant. It behaves like an annual plant: it grows rapidly from subterranean tubers in the spring, tops out in late summer, and completely dies back and decays in the winter. This massive die-off can cause severe dissolved oxygen crashes in small ponds.

Key Battlegrounds

Lake Gaston: Straddling the NC/VA border, this lake formed a massive coalition of homeowners and state agencies to fund a multi-million dollar, multi-year fluridone and grass carp program to successfully suppress thousands of acres of hydrilla.
The Eno River: Unlike lakes, rivers present a unique challenge because herbicides wash away. The Eno River required a highly specialized drip-system of fluridone to protect native species while slowly killing the hydrilla.
Lake Norman: The state's largest man-made lake has utilized strictly controlled stockings of triploid grass carp to manage outbreaks in the shallow coves without devastating the main lake's fisheries.

State-Led Coordination

Because hydrilla grows rapidly in the summer, North Carolina focuses on early-season intervention. The state operates an Aquatic Weed Control Program that provides technical assistance and cost-sharing to local governments battling the weed.

Management relies on attacking the plant before it can drop its winter tubers. If the tubers are allowed to drop in late August, the infestation is guaranteed to return the following spring. Thus, NC relies heavily on early-summer systemic herbicide applications and sterile carp.

Explore Related Topics

Frequently Asked Questions About Hydrilla in North Carolina: The Monoecious Migration

References

Information presented on this page is supported by peer-reviewed research, federal agencies, and state resource management programs.

U.S. Geological Survey (USGS) – Nonindigenous Aquatic Species Databasehttps://nas.er.usgs.gov
U.S. Army Corps of Engineers – Aquatic Plant Control Research Programhttps://www.erdc.usace.army.mil
NOAA Aquatic Invasive Species Programhttps://www.noaa.gov