ANOTHER INVASIVE AQUATIC PLANT FOUND IN THREE LAKES
Curly Leaf Pondweed
Curly-leafed pondweed, or Potamogeton crispus, gets its name from its rippled, wavy, and crinkled submerged leaves. The leaves are often compared to small lasagna. The leaves have a rounded tip and small “teeth” along the edge. Curly-leafed pondweed can be an aggressive invader that can cover large portions of lakes and will grow in water up to 15' deep. It is a non-native plant and should be removed where possible. In early summer of 2006, we found and pulled out one patch in Waccabuc. In 2007 and 2008 we found growing plants in a Waccabuc cove and a stand at the west end of Oscaleta. Despite pulling, it has continued to spread. Curly-leaf pondweed can be found at the west end of Oscaleta, throughout the channel, and in many places in Waccabuc, including the north cove. Please keep an eye out, report any new infestations, and pull all that you can!
Young curly leaf pondweed plants can form under ice cover during late winter, which makes this invasive one of the first nuisance aquatic plants to emerge in the spring. Curly leaf pondweed spreads in many ways: turions, which look like small brown pine cones, are dispersed by water movement; established plants form large colonies from rhizomes; and curly leaf pondweed can also spread by fragmentation.
Impacts: Curly-leaf pondweed is a highly competitive plant, capable of rapid growth and spread. Infestations may displace native species, reduce biodiversity, impede recreational activities, and reduce property values. Unlike many plants, curly-leaf tends to die back during the heat of the summer, and then regrow in the cooler waters of fall. As the dense mats of vegetation decay, available oxygen in the water may be depleted. The resulting anoxic (low oxygen) conditions may lead to fish kills and harm other aquatic organisms. Nutrients released from the decaying plant matter may also contribute to cultural eutrophication and algae blooms.
At the early stage of infestation, we might have been able to control this plant by hand harvesting. However, at this point, it is quite widespread in Oscaleta and Waccabuc. Local control is probably the only feasible option to keep it from becoming a nuisance at your waterfront. If you spot it, pull it out by the roots, carefully collect all the pieces, and dispose of the weed away from the water. Be sure to collect any turions that may come loose as you pull the plant.
This plant most likely came to our lakes as a “hitchhiker” on a boat. The plant is present in Lake Katonah and Lake Truesdale, where they use herbicides as an annual control. Please ensure you carefully inspect all boats or water toys that come into our lakes. Also please be careful to dispose of unused bait and don't take it from one lake to another.