Phragmites, or Common Reed, is an alien invasive aquatic plant that has the potential to degrade wetlands. The Georgian Bay Association encourages removal of invasive Phragmites because of the threat it poses to the biodiversity of the Georgian Bay area.
The plant’s scientific name is Phragmites australis. Introduced to North America more than 100 years ago, Phragmites has spread widely and is becoming rooted across Canada, including around Georgian Bay. Canada has labeled Phragmites one of Canada’s worst invasive plant species. Why? It can take over wetland habitats, crowd out native plants, and reduce habitat for a wide variety of animals, including species at risk. In North America there are no pests or pathogens to keep Phragmites populations in check. There is a closely related, native subspecies of Phragmites that is not invasive and is a modest component of many healthy wetlands.
How to Identify Invasive Phragmites
Dense stands or monoculture (up to 200 stems per square metre)
Height to 5m (16 ft.)
Flowers August – September
Seed heads dense, full and prolific
Leaves wide, dark blue-green at about 45 degree angle to stem
Stems rough, dull, rigid and tan colour at base
Native (non-invasive) Phragmites
Sparse stands with other species
Height to 2m (6 ft.)
Flowers July – August
Seed heads smaller, less dense
Leaves narrow, light yellow-green at about 30 degree angle to stem
Stems smooth, shiny, flexible and red/chestnut at base
Method of Control
Phragmites is primarily a concern in wetlands. In Ontario herbicides may be used to control Phragmites on dry land; licensed applicators can be hired to do so, or plants may be mowed in the spring while short. However, no herbicides for Phragmites control are approved for use in aquatic environments (this may change eventually but the review/approval process will take some time). Consequently, mechanical removal is the only practical method1 for “grass roots” efforts to control the spread of Phragmites.
Pilot projects undertaken with the assistance of Georgian Bay Forever (GBF) developed the following recommended approach for removal of stands of invasive Phragmites.
Undertake removal in late July/early August when the plants have reached full size and
seed heads are formed but not ripe for dispersal. The objective is to remove as much of
plants’ biomass as possible before seeds disperse.
Cut (do not pull out) the stems at a height of 10cm (4 in.) or less. This can be done with a
machete, pruning knife, scythe, power brush-cutter, or other appropriate tool.
For small stands it may be possible to dig out the plants including their roots/rhizomes.
However, this is very hard work and it is necessary to ensure that all roots/rhizomes are removed lest these drift away and spread, or become the basis for reproduction the following season.
Gather cut vegetation in a dry location away from water. Do not place cut vegetation in your compost pile or leave it near the shoreline. There are three options for proper disposal:
o Take it to a municipal disposal site; contact your municipality to ensure that your local disposal site is able to dispose of the cut vegetation properly
o Cover the cut vegetation with a tarp and leave tarp in place through the next growing season
o Allow the vegetation to dry out and burn it, subject to municipal by-laws. Be prepared to cut vegetation again after a year has passed. Experience has shown that it will come back, but less prolifically, because the roots/rhizomes will have less energy stored. More desirable native plants should begin to seed in and grow. A third cut may be required.
Removal of Invasive Phragmites from Crown Land
Aquatic habitats where invasive Phragmites has become established are likely to be provincial Crown land (generally Ontario lakebeds are property of the Crown in Right of Ontario). The Ontario Ministry of Natural Resources and Forests (OMNRF) administers Crown land. OMNRF will not likely require that formal approval be obtained to remove invasive Phragmites. When removing Phragmites be certain not to harm species at risk or other animal species. Consult your local OMNRF office where appropriate.
Good information is available on the Internet. Simply search under “Phragmites control”. Publications available for downloading are useful, especially for species identification and background. However, United States based information focuses on herbicide use; herbicides are not licensed for aquatic use in Ontario. Some good sources of information include:
www.stoptheinvation.ca - A website dedicated to encouraging community action to address invasive Phragmites; you can sign up for social media updates
www.opwg.ca - the website of the Ontario Phragmites Working Group www.web2.mnr.gov.on.ca/mnr/Biodiversity/Invasive_Species/Phragmites_Fact_Sheet.pdf - OMNRF Phragmites Fact Sheet https://www.michigan.gov/documents/deq/deq-ogl-Guide-Phragmites_204659_7.pdf - A Landowner’s Guide to Phragmites Control (State of Michigan)