At 16′ in height, common reed (Phragmites australis) may be the tallest native or naturalized grass in the state. It is common in wet and muddy areas on lake shores, alongside streams, and in marshes, sloughs, and roadside ditches.

There are three subspecies of common reed, two of which are found in Minnesota. One of these, European common reed, is an invasive plant from Europe, Asia, and Africa that threatens our natural wetlands and shores. The other, North American common reed (Phragmites australis ssp. americanus), is native to Minnesota. North American common reed is distinguished by less dense stands that do not crowd out other native plants; lighter colored foliage; shiny, smooth stems; the presence (sometimes) of small black fungal spots on the stem; leaves that fall off in the winter exposing a reddish stem; a less dense inflorescence that will not persist through the winter; and microscopic differences in floret parts.

http://minnesotaseasons.com/Plants/North_American_common_reed.html