Non-native subspecies of Phragmites (Common Reed) (Phragmites australis subsp. australis)

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Non-native Phragmites subspecies on the left, native Phragmites subspecies on the right. Photo by Mary Meyer, U of MN.

Stand of non-native Phragmites.  Photo by S. Kelly Kearns.

Description:

Appearance: Phragmites australis subsp. australis is a non-native subspecies of common reed.  The native common reed is Phragmites australis subsp. americanus.  Both subspecies are perennial wetland grasses and both are present in Minnesota.  The invasive subspecies can grow over 12 feet high in dense stands.

Leaf blades: Stems of native subspecies are smooth, stems of invasive subspecies are ribbed.  Leaf sheath of the native is easy to remove or falls off; invasive is difficult to remove.

Flowers: Flower head of native species is sparse, flower head of invasive subspecies is dense.

Roots: Deep and dense network of roots and rhizomes.

For help distinguishing native vs invasive Phragmites see: Mistaken Identity - Invasive Plants and their Native Look-Alikes PDF icon or Cornell University.

 

Ecological Threat:

  • Invades lake shores, wetlands, rivers, and roadsides.
  • Mixed wetland communities are replaced by near monocultures of invasive Phragmites/common reed causing changes in ecosystem processes (hydrology, nutrient cycles) and negative impacts on native plants and wildlife.
  • The non-native subspecies of common reed is a MDA Restricted Noxious Weed in Minnesota. Importation, transportation, and sale of the non-native subspecies of common reed is prohibited.

 

Control Methods:

Mechanical: Mowing 3-5 times during the growing season can decrease the density of Phragmites. 

Chemical: Herbicides such as gylphosate (Rodeo) can be effective.  Be sure to use herbicides approved for use near water.  Follow-up with a burn in late fall for additional control.

Note that control of emergent vegetation on public waters requires a permit.

 

Native Substitutes:

Additional Resources