Also called American Pondweed, they have two different kinds of leaves -- oval ones that grows up to five inches atop the water, and elongated ones that grows up to 8 inches underwater. Blooms from June through August. Pondweeds provide food and cover for aquatic animals.
Hand-pulling Longleaf Pondweed to control its spread in small waterbodies for recreational and aesthetic reasons, has been found to be effective. (AN AQUATIC PLANT MANAGEMENT PLAN UPDATE FOR NAGAWICKA LAKE, WAUKESHA COUNTY, WISCONSIN: 2011).