• facebook
  • twitter
  • YouTube
  • RSS feed
  • 651-201-6000
  • 800-967-2474
  • 711 TTY

NodeFire Save Document
Home > Plants, Pests & Pest Control > Pest Management > Noxious & Invasive Weed Program > Weed of the Month > November 2015 - Non-native Phragmites

November Weed of the Month: Non-native Phragmites

Non-native Phragmites in flower. Photo courtesy Caleb Slemmons, National Ecological Observatory Network, Invasive.orgThe Weed of the Month for November is a warm season perennial semi-aquatic grass species called non-native Phragmites (Phragmites australis ssp. australis). Non-native Phragmites threaten wetland areas and can outcompete native plant species with its prolific growth and dense growth habit.

Non-native Phragmites reaches a height of 15 feet. It has a ridged, hollow stem with a rough texture. The blue-green leaves are 15-20 inches long by one inch wide and remain on the stem through the winter. It forms purplish flowers at the tips of the stems, and produces thousands of grayish seeds that have a fluffy appearance. The plant forms a dense monoculture both by seed and by vigorous roots that can spread more than 10 feet laterally and several feet deep.

Non-native Phragmites grows in a variety of aquatic to semi-aquatic habitats in Minnesota. It colonizes disturbed areas such as roadsides, gravel pits, shorelines, wetlands, marshes, flooded areas, and streambanks. Seeds are disbursed through wind, water, animals, and human activity. Phragmites also reproduce be above and below ground stems that send up new shoots to form dense clumps. The plant can regenerate from root fragments that are moved by flooding or contaminated soil.Management of non-native Phragmites requires commitment and multiple years of monitoring.

  • Management plans that include native species restoration have greater success in reducing non-native Phragmites infestations over time.
  • Mechanical control is difficult and risks spreading the seeds and root fragments to new areas, but can be used in conjunction with other control methods, such as herbicide treatments.
  • Prescribed burns can be a useful control method and works best in conjunction with herbicide applications. Contact the Minnesota Department of Natural Resources to learn more about prescribed burning practices and regulations.
  • Intensive grazing can help reduce seed production if used in conjunction with an herbicide treatment.
  • If using herbicide treatments, check with your local University of Minnesota Extension agent, co-op, or certified landscape care expert for assistance and recommendations.

More information is available at Great Lakes Phragmites Collaborative.