Is hydrilla in the Chesapeake Bay?

Yes, hydrilla thrives in the tidal freshwater portions of several major Chesapeake Bay tributaries, including the Potomac and Susquehanna rivers.

Does hydrilla grow in Deep Creek Lake?

Yes, Deep Creek Lake, Maryland's largest inland lake, has an ongoing hydrilla infestation that is carefully managed to balance recreation with fish habitat.

What type of hydrilla is in Maryland?

Maryland deals almost exclusively with the cold-tolerant monoecious biotype, which dies back every winter and regrows from tubers in the spring.

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Hydrilla in Maryland: The Chesapeake Watershed

Explore how the monoecious strain of hydrilla impacts Maryland's inland lakes and the delicate ecosystem of the Chesapeake Bay tributaries.

A Dual-Front Battle

Maryland faces a unique challenge in the fight against Hydrilla verticillata. The state must manage the aggressive, cold-tolerant monoecious biotype across two very different ecosystems: high-elevation inland reservoirs and the tidal freshwater tributaries of the Chesapeake Bay.

The presence of hydrilla in the state highlights the complex debate over invasive aquatic plants, as it simultaneously degrades recreational access while providing undeniable benefits to water clarity and sportfish populations.

Major Infestations

Deep Creek Lake: Located in the mountains of western Maryland, this popular resort lake discovered hydrilla in 2013. The Maryland Department of Natural Resources (DNR) uses highly targeted herbicide applications to suppress the weed in high-traffic coves while protecting native vegetation.
The Potomac River: Shared with Virginia, the tidal freshwater stretches of the Potomac near Washington D.C. are heavily choked with hydrilla during late summer, severely impacting marinas and rowing clubs while simultaneously supporting a world-class bass fishery.
Upper Chesapeake Tributaries: Hydrilla has spread to the Susquehanna Flats and other low-salinity reaches of the upper bay, where it outcompetes native submerged aquatic vegetation (SAV) like wild celery.

Management in the Watershed

Because the Chesapeake Bay is the subject of one of the largest ecological restoration efforts in the world, the management of hydrilla is highly scrutinized. The use of biological controls like triploid grass carp is strictly prohibited in the tidal watershed to prevent fish from escaping into the broader bay ecosystem.

Instead, Maryland relies heavily on mechanical harvesting around critical infrastructure (like marinas) and highly regulated, localized herbicide applications to manage inland lakes before the plants can drop their winter tubers.

Explore Related Topics

Frequently Asked Questions About Hydrilla in Maryland: The Chesapeake Watershed

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