Phragmites or Common Reed, Phragmites australis

Common Reed grows on the edges of wetlands. It is a perennial grass that grows to heights of 13 feet. It has long narrow leaves and plumes of flower spikes that can be 6-12 inches long. Phragmites can spread by seed or through underground rhizomes, which have a growth rate of 3 or more feet per year. Common Reed is thought to be the most widely distributed flowering plant in the world. There are native species, but the highly aggressive, invasive form that is taking over US wetlands originated in Europe. Late summer cutting, burning and use of systemic herbicides are methods of control. Only one herbicide is registered for aquatic use in Michigan. That is glyphosate, a broad spectrum herbicide that will also kill non-target species, so great care must be taken when using it. Re-treatment is usually necessary every 3-5 years, so it is important to eradicate Phragmites before it can establish itself.

more info: http://www.invasiveplants.net/phragmites/