7 tips to help you identify invasive Phragmites

Are you concerned that you may have the wrong plant for crowd-mapping invasive phragmites when using the Phragspotter™ App? Or even scarier –  are you frightened you have invasive Phragmites australis on your property or invading an area you really care about?

Here are some tips I’ve collected to help you identify the invasive Phragmites australis subsp. australis.

1. Yes – there is a a NATIVE Phragmites (Phragmites australis subsp. americanus) that is not a threat to biodiversity. How can you tell them apart? There are fantastic details and pictures of the many differences including a downloadable brochure from the Michigan State University Extension , but I will hit a few highlights here:

Native vs. Non-Native Phragmites

Characteristics of Invasive Phragmites

2. Dead stems and new growth on invasive Phragmites are often found together as dead stems can comprise a high percentage of a stand. Here are pictures of a more established larger mono-stand and an evening picture of a smaller stand that will grow denser with time.

Mid June Phragmites satnd

Small Stand Invasive Phragmites



3. Leaves of  growing invasive Phragmites plants are green, with a blue-grey cast.  I like Cameron Wood’s descriptions of these plants, as narrow longish triangles that can look a lot like cornstalks without the corn.

Phragmites leaves

4. Seedheads on invasive Phragmites are quite robust. In early July to August, the seedheads have a purplish tinge to them. Since the flowering season has not fully arrived, my pictures below show a seedhead on a dormant stem and one from June –  you can visit the Wisconsin Horticulture site for a great picture of a flowering (purplish) seedhead. Note – Young Plants may not generate seedheads the first few years.

Seedhead of Phragmites Dead stem.

Seedhead on Dead Stem June 2015

5. The base of stems on invasive Phragmites  are tan coloured and rigid. Growing Phragmites  have sturdy greenish stems that seem to have small discoloured regular breaks with dark rings reminiscent of green bamboo.

Phragmities stems

6. Rhizomes (and stolons) of invasive Phragmites are the below and above ground creepers that help the plant spread.  New plants start sending out tendril-like horizontal limbs  called rhizomes and stolons that develop new shoots every 30 to 40 cm. Stolons can grow as much as 43 feet and can have reddish colour; while rhizomes can extend as much as 70 ft. Rhizomes are particularly effective spreaders since they ‘travel’ underground and severed parts of rhizomes can live and thrive independently starting new stands. See a picture of stolons by visiting this page from the Michigan State University Extension under the paragraph about reproduction.

7. Where can invasive Phragmites be found?  Invasive Phragmites flourish in sunny wetlands or open sunny areas that have experienced some disturbance to the ground conditions. They have a harder time manifesting in environments of very mature and very dense vegetation. Here are 6 general areas where invasive Phragmites can be found:

  • Phragmites pose the biggest threat to biodiversity in wetlands, but they can also thrive and be found in many other environments.
  • The biggest spread vector in my opinion seem to be ditches or culverts beside highways and roads like the stands slinking up the 400 from Toronto. Phrag stand near Port Severn
  • Rail line corridors
  • Beaches – the density and height of Phragmites stands is an issue for water access. See next point.
  • Dry or pebbly shores – no approved chemical treatment in Ontario for near water or water use. Invasive Phragmites that manifest themselves in these areas are labour intensive to remove.
  • Along rivers and in shallow still water – previous 2 points apply.

7. Young  invasive Phragmites can be difficult to pinpoint. They aren’t always with a bunch of dead stems, and they can be more sparsely distributed until the plant stand becomes established. Being young, the plants are smaller but grow quickly and may not flower or produce legitimate seeds for a couple of years. Do what you can to be very observant, as catching Phrag at the early stages is easier and less costly to put a plan in to control. Lets “App it, Mapit, and Zap it”   – the strategy devised by stoptheinvasion.ca.

If you have any pictures you want to share of native or non-native Phragmites, please contact me at bywiringup@gmail.com.  See you on The Bay, Heather Sargeant.

Close-up of young phragmiteesthumb_IMG_3626_1024

Sources used in this post include:


1 thought on “7 tips to help you identify invasive Phragmites

  1. Pingback: How to remove an invasive Phragmites stand? | Woods Bay Phrag Fighters

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