Here’s our first monthly “Masters of War” series post, which highlights invasive species in Michigan so you can recognize and help report them. I thought we’d start off with this particular plant since our first featured scientist, Jake Bonello, spends a lot of time mapping its location and treating it.
Name: Phragmites australis, commonly called Phrag (pronounced “FRAG”) or Common Reed Grass. It should be noted that there is a native strain of Phragmites australis (subspecies americanus) which is not invasive. However, an introduced strain (Phragmites australis subsp. australis) from Europe and Asia is invasive here and is the plant I’ll be describing in this post.
Native Range: Europe and Asia
Description: Above ground, Phragmites australis is made up of tall stalks, 6-18 feet high, with alternate leaves along the stem that are about 1.5 inches wide and 8-20 inches long. The flowers (or inflorescences) are found at the very top. They look almost feathered and are a deep purple-brown. Later in the season, the flowers give way to small spikelets that grow long, silky hairs which help the seeds spread in the wind. Below ground, Phragmites is a dense network of hollow rhizomes which spread horizontally to create new shoots above the ground. Because of this, it can spread quickly in the right conditions (as much as 5 meters per year).
Habitat: Phragmites is a very resilient species and can tolerate a wide range of conditions. It is commonly found in wetlands where it can grow in soil with no visible standing water or up to 3 feet of standing water. It is often found in roadside ditches and in estuaries (where rivers meet the ocean) because it is salt tolerant.
Positive Attributes: In its native range, Phragmites australis is quite popular for waste water remediation. Because it colonizes quickly and is known to absorb many harmful chemicals, as well as excess nitrogen and phosphorus (found in animal waste and fertilizer runoff), it is excellent for helping to rid waste water of these substances. It has also traditionally been used for purposes like roof thatch in the British Isles, instrument making in the Middle East, paper production in Romania, and was even used as flour in these regions. It is also important for conservation in Europe and Asia where several species of bird use stands of Phragmites australis as their preferred habitat. It was also traditionally used as fodder for grazing animals.
Negative Ecological Impacts: Unfortunately, a lot of the positive attributes of Phragmites are what make is such a successful invasive plant here in Michigan. It is hard to contain because it spreads quickly via underground rhizomes, which are difficult to remove and often cannot be removed due to the delicate nature of wetland ecosystems. It also spreads by wind-borne seeds which are tiny and difficult to control. This plant can grow nearly anywhere that is damp but can also tolerate up to a meter of standing water and even salty water, which means the growth of Phragmites is not limited by these habitat parameters. Because this plant is not used as grazing fodder in North America and, in general, wildlife here does not eat this plant, it often grows unchecked into huge, very dense stands that can span for miles along coastlines and roads. Most native birds and mammals will not use these dense stands as nesting habitat, which is a concern for the conservation of species that normally nest on coastlines. Habitat loss along coasts is already high since people tend to build communities along the water, and further loss due to Phragmites has drastically reduced nesting habitat for frogs, fish, birds (especially waterfowl), muskrat, and many other animals. Because Phragmites grows so tall, it out-competes native plants by shading them from the sun, which results in the loss of biodiversity in these areas and allows Phragmites to grow in a monoculture (large stand of only one kind of plant). This endangers the native plants that compete for coastal habitat, like wild rice, cattail, and wetland orchid species.
Key Identifying Characteristics: There are three obvious things you can look for:
- Height – few wetland plants, especially grasses, grow as tall as Phragmites australis does.
- Inflorescences – The flowers on this plant are feathery and unmistakable, as you’ve seen from the pictures included in this post. Other plants may have similar flowers, but often they are much shorter than Phragmites.
- Monoculture – If you all you see is a plant that looks like Phragmites in a big dense patch, in all likelihood, it IS Phragmites.
How to report this species properly: Use this link for the Midwest Invasive Species Information Network. They’ll ask you to register (one time only) before you can report your sighting, but the good news is that once you’re registered, you’re all set to report again next time you find an invasive species! You can also learn more about invasive species using fact sheets on this site or browse their data which is pretty cool.
More Information: There are literally thousands of studies that have been published about Phragmites australis. Here are a few good links to check out if you want to know more, but keep in mind you could read for about this plant for weeks and still just be scratching the surface:
Great Lakes Phragmites Collaborative
USDA National Agriculture Library
US Fish & Wildlife Service Fact Sheet