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Invasive Phragmites

Invasive phragmites (Phragmites australis), a European common reed, is a tall, perennial grass that is invading wetlands, roadside ditches and agricultural lands across Elgin County. Invasive phragmites (pronounced “frag-my-teez”) differs from their native counterpart (Phragmites australis americanus) by growing in extremely dense stands crowding out other species.

Invasive phragmites is very aggressive and will out-compete other native species for water and nutrients. They spread rapidly through seed dispersal and have an intricate system of specialized roots that readily grow into new plants. It is very difficult to completely eradicate invasive phragmites once it has been established.

Our table below indicates the differences between the invasive and native species.

 Invasive phragmitesNative phragmites
Latin namePhragmites australis subsp. australisPhragmites australis subsp. australis
Look
  • Dull, tan or beige stems
  • Blue-green leaves that are darker than the native variety
  • Large, dense seed heads
  • Shiny, reddish-brown stems
  • Yellow-green leaves
  • Smaller, sparser seed heads
Growth
  • Grows in stands that can be extremely dense with as many as 200 stems per square metre
  • Stands include both live stems and standing dead stems
  • Grows in stands that are usually not as dense as the invasive plant
  • Frequently mixed with other plants species
Density
  • Is so dense that it crowds out other species
  • Other species have enough light and space to grow in same area
Height
  • Up to 6 metres
  • Up to 2 metres
Common locations
  • Roadside ditches (very common)
  • Wetlands
  • Agricultural lands
  • Unlikely to be found in roadside ditches
  • Commonly interspersed with other plant species
Leaf sheaths
  • Dead leaf sheaths stay on stem
  • Dead leaf sheaths are loose and drop off easily in the winter, leaving bare stems standing in the spring
Stems
  • Stems break down very slowly, forming a dense thatch
  • Stems break down quickly

Additional resources for identifying invasive vs. non invasive phragmites

Ontario Phragmites Working Group – Native vs. Invasive

Great Lakes Phragmites Collaborative – Native vs. Non-Native

  • Crowds out native vegetation resulting in lower plant diversity
  • Provides poor habitat and food for local wildlife
  • Growth can impact local water levels and drainage infrastructure
  • Increase fire risk as stands are composed of dead stalks
  • Causes increased risk to road safety due toreduced sightlines
  • Interferes with agricultural crop growth
  1. Do not purposely plant it. Invasive phragmites is available at garden and horticultural centres. Learn to identify the difference between invasive and native species or select other native grassess for gardening.
  2. Avoid the spread of seeds to new sites. When leaving an area containing phragmites, brush off clothing and clean equipment.
  3. Do not compost invasive phragmites. The seeds and rhizomes (root system) can survive and start growing in compost. Cut plants can be left in place to decompose.

Methods used to control phragmites vary based on specific site characteristics. A combination of a non-chemical method (mowing or cutting) followed by a specific herbicide spray application applied by licensed applicators is one of the most effective ways to control phragmites. However, herbicide application may be prohibited in areas close to water and best management practice guidelines must be followed. Spot herbicide application over a 3-5 year period may be required to completely eliminate phragmites growth in targeted areas.

Control methods that don’t work

  • Cutting without use of hebicides
  • Cutting or treating only some of the phragrmites grouping
  • Cutting the plants afer a sead head develops
  • Using a lower concentration of herbicide, applying at the wrong time, or not under proper weather conditions
  • Cutting before or too soon after treatments

Control methods that do work

Please visit the Government of Ontario website for additional information on best management practices for phragmites.

Elgin County has been working with its member municipalities since 2020 in a long-term strategy to tackle invasive phragmites.  Each year phragmites locations are identified along public roads across the County and these areas are treated with approved herbicides and then mulched following industry best practices.  The program has been successful to date to reduce the prevalence of invasive phragmites along roadways, however, ongoing annual treatment will continue to be necessary to deter re-emergence.

Elgin County Roadside Phragmites Locations

Click Here
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