Phragmites, a tall perennial reed grass, are common in Greater Sudbury. Both native and invasive kinds (called ‘subspecies’) can be found here.
The invasive subspecies is quite aggressive. It grows in dense stands up to five metres tall and has very large seed heads. These stands spread over the years, steadily decreasing habitats for most other plants and animals. Much of its biomass can be found underground in an intricate system of roots and rhizomes, which are modified stems that extend underground and send out roots and shoots at various intervals. Toxins released from its roots degrade the surrounding soil, hindering the growth of other plants, if not killing them outright.
It can easily outcompete native plants for water and nutrients, alter wildlife habitat, reduce visibility along roadways and even impact recreational activities like swimming, boating and fishing. In 2005, Agriculture and Agri-Food Canada singled out invasive Phragmites as the country’s worst invasive plant species.
The plants spread mostly through ‘runners’ (modified stems), either intact or as fragments. Seeds also play a role in the spread of Phragmites but these tend to have low rates of germination.
“A coordinated, regional approach is essential to effectively manage this invasive species. By working proactively and engaging communities early, we can prevent long-term ecological damage and protect the natural spaces that support biodiversity and climate resilience,” says Miranda Virtanen, Executive Director of the Junction Creek Stewardship Committee (JCSC). The group has been working with community partners to raise awareness about the issue.
JCSC has surveyed over 100 kilometres of Junction Creek to date. In the upper reaches of its watershed alone, over 30 patches of Phragmites were found covering a total of 23 acres.”
The effects of invasive Phragmites include:
- Loss of biodiversity and species richness: Their monoculture stands crowd out native vegetation and hinder native wildlife from using the area.
- Loss of habitat: Stands decrease available natural habitat and food supply for a wide range of wildlife species, including those that are at risk.
- Changes in hydrology: Their presence lowers water levels, leading to changes in the water cycles of a system.
- Changes in nutrient cycling: Their stalks are made of a very inflexible structural material; it breaks down slowly and slows down the release of nutrients.
- Increased fire hazards: A stand has a high percentage of dead stalks, which are dry and combustible, so there is a greater risk of fire.
- Economic and social impacts: Their presence can affect agriculture and crops, resulting in economic losses, affecting property values, and raising esthetic concerns.
What can I do?
1. Learn to identify and distinguish between the native and invasive species. Native Phragmites are generally no taller than two metres, whereas the invasive type can reach a height of up to five meters (15 feet). In addition to stand height, other features to look at include stand density, stem colour, leaf colour and seedhead density. For more information, visit Identifying Native vs. Invasive Phragmites | Great Lakes Phragmites Collaborative.
2. Report invasive species sightings to a national network of expert verifiers using EDDMapS; apps are available for iOS and Android smartphone devices.
3. If you are a gardener, only use native or non-invasive plants. Ask at your local garden centre for plants that are not invasive.
4. If you’re out hiking, inspect your shoes and equipment closely and clean everything off well before you leave the area. Without taking this precaution,, seeds and fragments from invasive plants could travel with you and spread even further. Junction Creek has boot brushes available at some trails to help. Last fall, a trailside boot brush station was installed in the arboretum along the Percy Park Trail.
Why is the threat so acute in Sudbury?
Invasive Phragmites continue to spread north from southern Ontario, making it an emerging threat to the Greater Sudbury region. Specific geographical and environmental conditions here also make controlling the plant a significant challenge.
Greater Sudbury’s challenges include:
- Extensive water networks: Sudbury is particularly vulnerable to the spread of Phragmites, thanks to its over 330 lakes and network of rivers and streams. Seeds and plant fragments can travel long distances via flowing water, which increases the risk of new infestations.
- Industrialized sites, which are common in Greater Sudbury, allow Phragmites thrive since they are tolerant of disturbed areas.
- Large geographic area: Greater Sudbury’s vast size—an area over 3,000 square kilometres—makes comprehensive monitoring efforts challenging, but they are essential to accurately assess the extent of infestations.
- Native vs. invasive subspecies: The coexistence of both native and invasive Phragmites subspecies here makes identification and reporting efforts more difficult; it requires specialized training and careful monitoring to avoid mistakenly removing native stands.
Due to these unique challenges there is an urgent need for collaborative, region-wide initiatives, which would help address existing gaps in the mapping, monitoring, and management of the plant in Greater Sudbury. Controlling invasive Phragmites before it becomes well-established will reduce the environmental impacts.
With support of the Ontario Phragmites Action program and supporting funder, the Ontario Ministry of Natural Resources, the JCSC is partnering with Conservation Sudbury, the City of Greater Sudbury, and Laurentian University’s Environmental Sustainability Committee to combat the spread of invasive Phragmites in the region. This project will lay the groundwork for long-term control by prioritizing accurate identification, community engagement and strategic removal efforts.
For more information on how to properly identify and manage invasive species, visit the Invasive Species Centre website.
Learn more about the City of Greater Sudbury and its commitment to reducing greenhouse gases and helping the community achieve its net-zero goal by 2050.
If you have an environmental topic or project you’d like the City to highlight, contact Jennifer Babin-Fenske at [email protected].
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