Aquatic Plants

Aquatic plants, such as Hydrilla, Eurasian watermilfoil, and Curly Pondweed can have huge impacts on fishing, boating, and even swimming in Wyoming waters. Be sure you are not spreading these unwanted plants to Wyoming by making sure your boat and gear is Clean, Drain, and Dry.


Origin: Asia

Distribution: Throughout the United States. Hydrilla is not known to be present in Wyoming.

Impacts: Clog lakes, out-compete natives, alter water chemistry, reduce fish forage.

Dispersal: Transported as small plant fragments attached to trailered watercraft, or through the aquarium trade.

Characteristics: Heavily branched, small, pointed leaves-5 per whorl. Coarse teeth along leaf margin, midrib often red color, submersed, rooted, perennial.

Additional Hydrilla Information

Hydrilla (Info Sheet)

Eurasian Watermilfoil

Origin: Europe, Asia

Distribution: Throughout the United States. Eurasian Watermilfoil is not known to be present in Wyoming but is present nearby in Colorado.

Impacts: Displace natives, clog lakes, reduce fish forage and invertebrate abundance.

Dispersal: Transported as small plant fragments attached to trailered watercraft.

Characteristics: Long, branched stems, finely divided leaves, 3-5 per whorl, threadlike leaflets – pairs of 12-20, submerged, perennial.

Additional Eurasian Watermilfoil Information

Eurasion Watermilfoil (Info Sheet)

Curly Pondweed

Curly pondweed has limited distribution in Wyoming. It was found in Lake DeSmet in 2011. In 2012, it was discovered on the North Platte River between Seminoe Reservoir and Pathfinder Reservoir (an area referred to as the “Miracle Mile”) and also at New Fork Lake. 

Origin: Eurasia, Africa and Australia

Distribution: Found in Lake DeSmet, Newton Lakes, Beck Lake, Shoshone River. North Platte River (Miracle Mile), and Keyhole, Boysen, Deaver, Wheatland #3 and Pathfinder Reservoirs, Wyoming.

Impacts: Competes with native plants reducing plant diversity and forms dense mats that impact water-based recreation.

Dispersal: Reproduces by seed which can be easily transferred in mud or water. It has been introduced into new areas by accidental introductions and as an ornamental plant.

Characteristics: Leaves are arranged alternately along the stem, and are submersed. The leaf margins are distinctively wavy or 'curled‘ with a prominent red-tinged midvein.

Additional Curly Pondweed Information

Curly Pondweed (Info Sheet)


If you see invasive plants on your boat or equipment or in Wyoming waters, please report it to 1-877-WGFD-AIS or
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