Invasive Phragmites is a tall, densely growing grass that can take over large areas, push out native vegetation, and reduce habitat quality for wildlife.
What it is
Phragmites australis, also known as common reed, is a tall, perennial grass. It is found in wetlands, riparian areas, shorelines, and other wet areas such as roadside ditches.
Both native and non-native genotypes of Phragmites are present in Minnesota. The native and non-native types can be difficult to distinguish from one another. For this reason, non-native Phragmites has been dubbed a “cryptic” invader. Without coordinated effort to distinguish and map native and non-native forms, the true distribution of invasive Phragmites in the state cannot be determined. This gap poses two risks: lack of action in response to new invasions or indiscriminate treatment that damages the native subspecies.
What it affects
Invasive Phragmites is an ecosystem engineer that benefits from human-caused disturbances on the landscape. Invasive populations in North America have been shown to alter the hydrology of wetland systems, lower plant diversity, impact food webs, and reduce diversity and abundance of invertebrates, fish, and waterbirds.
Where it's found in the U.S.
Phragmites has a global distribution, being found on all continents except Antarctica. The lineage that is invasive in North America – from the Atlantic coast westward to Minnesota and beyond – is native to Europe. This form has spread across North America over the past 150 years, almost entirely displacing native Phragmites in regions where it has long been established.
Where it's found in Minnesota
In 2017, more than 150 professionals and citizen observers requested kits to participate in the MNPhrag Early Detection Project. Their contributions resulted in the documentation of over 200 unique populations of invasive Phragmites throughout Minnesota. See this MNPhrag Phragmites Locations Map to see the populations MAISRC researchers and collaborators documented.
How it spreads
Invasive Phragmites can spread both sexually (by seed) and asexually (clonally, including by stolon and rhizome fragments). When populations are producing large amounts of viable seed, spread across the landscape is more rapid and control is more difficult and expensive. The extent of sexual reproduction in Minnesota is still under investigation, but early viability studies show that viable seed is being developed in several populations in approximately the southern two-thirds of the state. See the Invasive Phragmites Viability Study tab in the MNPhrag Phragmites Locations Map for those locations. More trials will be conducted in winter 2018 to determine whether additional populations are developing viable seed.
How to manage it
MAISRC researchers have reviewed the published literature and other resources, and developed a general management recommendation for non-native Phragmites. You can find those recommendations here.
How you can help
Phragmites ID Guide
Not sure how to distinguish invasive Phragmites from its native counterpart? Click here to view or download the MNPhrag ID Guide.