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Invasive phragmites: the bully trying to take over our wetlands

Without proper management, Phragmites can get to an unmanageable size,
Invasive phragmites stand in Mackinac County, Michigan

Following is the monthly article from the Chippewa Luce Mackinac Conservation District

If you have driven down I-75 while traveling downstate, you have probably noticed large reeds with quite puffy seed heads, commonly in the median or in road ditches, maybe even in a swamp or marsh or any kind of wetland. Those reeds are probably a plant known as Phragmites.

Phragmites is a perennial wetland reed that can spread thousands of seeds on an annual basis. It has a root structure that contains both above-ground (stolons) and below-ground (rhizomes) that grow vigorously and deep.

This adaptation allows invasive phragmites to spread quickly and outcompete native species. In the summer, this quick-spreading reed will have blue-green blade-shaped leaves with a green and tan stalk, growing anywhere from six feet to twelve. Seed heads are typically very full and puffy with a purple-brown hue.

The Upper Peninsula is also home to a native Phragmites. This is typically not as tall as invasive Phragmites. It will have more yellow-green blade-shaped leaves with a green stalk that often has red at the base of each segment of the stalk. Stalks can get four to six feet tall. The seed head is typically more wispy and less full, with a more distinct brown color.

Unfortunately, in wetlands where there are both native and invasive Phragmites, identification can be difficult as hybrids can grow from cross-pollination. Typically, hybrid Phragmites will have characteristics of both Phragmites species combined. The characteristics of each hybrid plant can vary as it is hard to tell exactly how each stand will hybridize and what characteristics it will show.

Native Phragmites are beneficial compared to invasive Phragmites because native Phragmites filter the water without taking out beneficial nutrients. Invasive Phragmites, however, quickly drain a wetland of important nutrients such as nitrogen and phosphorus. This, in turn, can cause the wetland to be depleted of vital nutrients and oxygen, limiting its ecosystem services.

Another way invasive Phragmites are spread is through vectors such as humans and animals. One may think invasive Phragmites is beneficial to habitats, but it has been shown that birds and other animals struggle to navigate through invasive phragmites and the reed is too smooth to hold birds’ nests.

Additionally, invasive Phragmites have long been used as a natural camouflage by waterfowl hunters due to their abundance and thickness. This activity has led to increased spread and habitat loss. Invasive Phragmites also becomes dry and brittle every year creating dead biomass capable of being ignited by lightning strikes and starting a wildfire.

So, the next time you are adventuring through the Upper Peninsula, be on the lookout for this wetland bully.

Without proper management, Phragmites can get to an unmanageable size, creating opportunities for a greater spread of the plant and reduced availability for native plants.

Please report any sightings to MISIN or call Three Shores CISMA at 906-630-7139 if you are in Mackinac, Chippewa, or Luce counties.