Common Reed Grass (Phragmites australis ssp. australis)

Common Reed Grass (Phragmites australis ssp. australis)

Common reed grass (Phragmites australis ssp. australis) is an invasive perennial grass that is native to Eurasia.  It is not known for certain how it was moved to North America, but it likely arrived on the Atlantic coast accidentally via ballast materials in the late 1700s – early 1800s.  (Swearingen, J. and K. Saltonstall. 2010)

Since establishing in North America, Phragmites australis ssp. australis has spread throughout continental U.S. and to most provinces in Canada.  It prefers to grow in standing water but will tolerate growing in dryer areas.  It can easily be confused with a closely related native subspecies, Phragmites australis ssp. americanus.

 

IDENTIFICATION

Here are some key features that may help positively identify Common Reed Grass and distinguish it from its native relative:

Phragmites australis ssp. australis (Invasive):

  • Grows in dense stands and crowds out other species
  • Grows to be ~5 m tall, a much more robust plant than the native Phragmites
  • Lower stems are tan or beige-coloured
  • Leaves are arranged alternately and are a blue-green colour
  • The panicle inflorescence (seed head) is larger and more full than the native subspecies’
  • Begins growing earlier in the spring and grows later into the fall than the native subspecies

 

Phragmites australis ssp. americanus (Native):

  • Grows in a more scattered manner, mixed in with other native wetland species
  • Typically reaches 2 m in height
  • Lower stems are red
  • Leaves are yellowish-green, smaller than invasive Phragmites’, and distributed predominantly on the same side of the stem
  • The panicle inflorescence (seed head) is smaller and more sparse

 

Common reed grass (invasive ssp.) is considered a priority species for the PEI Invasive Species Spotters Network.  If you see this plant, please report your sighting.