invasive species Phragmites

It may be bending reality a bit to include these aquatic plant invaders in our regular ‘creature feature’ but we nonetheless believe it’s important to chronicle the damage these plants are leaving throughout the Cataraqui Region and far beyond.

Cataraqui Conservation will be sharing information and resources over the next few months to bring awareness around aquatic invasive species. Phragmites, along with Water Chestnut and Water Soldier are at the top of the ‘most wanted’ list from Cataraqui Conservation and other environmental organizations, including municipal, provincial, and federal departments this summer. Working with our partners a strategy has been formulated to start identifying and tracking infestations of Phragmites and other predatory plants to address areas of concern. Further articles and resources will be posted on the Cataraqui Conservation website and social media channels to outline what is being done and can still be done in the struggle to contain and control the spread of aquatic invasive species.

But let’s take a step back and identify the first aquatic invader in our series, Phragmites, and what devastating effects it could inflict on the area’s delicate ecosystems.

Also known as the European Common Reed or Phragmites australis ssp. australis, this aquatic plant is a subspecies of a family of large, perennial reed grasses that thrive in warm, temperate, and tropical wetlands throughout the world.

Originating in parts of southern Europe and Asia, these Phragmites are an invasive species, which means they pose a threat to similar native species, but also to other species of plant and animal life. What is not known is how they crossed the vast oceans to take up residence in North America, but what is known is the harm they cause.

According to information on the Ontario government’s invasive species website (, Phragmites is an aggressive plant that spreads quickly and out competes native species for water and nutrients by being taller growing (thereby blocking out the sun). The plant releases toxins known as phytotoxic allelochemicals from its roots into the soil to hinder the growth of and kill surrounding plants. While it prefers areas of standing water, its roots can grow to extreme lengths allowing it to survive in relatively dry areas.

By pushing out native species, this invader reduces biodiversity of plant life, which is necessary for a sustainable ecosystem, especially when considering the impact of climate change on all natural environments.

Phragmites grow fast (think of bamboo), which means they literally suck up more water than the native species do, causing lower water levels, which leads to a myriad of problems during times of low rainfall and drought, not to mention again altering the nature of the ecosystem.

If this weren’t enough, as the Phragmites grow taller and taller, the large stands of the plants become composed more and more of dried stalks, which become a fire hazard. Their presence in large quantities in waterways, lakes and wetlands can also create safety hazards on trails, roads, and can impede recreational activities such as boating, swimming, and fishing.

Dense stands of Phragmites which grow in irrigation culverts or stormwater management ponds can increase sedimentation and disrupt the flow and availability of water.

Some sources believe that there were few incidences of invasive Phragmites before 1910. Fifty years later they were found coast to coast and in northeastern parts of the United States and southeastern Canada, they are now the dominant form of the plant.

Many municipal bodies, lake associations, conservation groups and property owners have begun to band together to develop strategies to combat the spread of invasive Phragmites in the Cataraqui Region. When tackling an adversary such as this, the old adage about knowing your enemy is crucial. The first stage in fixing a problem is to identify it.

According to the Alberta provincial government, which is dealing with a similar invasive Phragmites challenge, these plants are “rigid, with many nodes and green, spear-like leaves that alternate and tightly adhere to the stalks, which can reach up to six metres [that’s METRES not feet] tall. Flowers are feathery spikes that range in colour from golden to purple in mid-summer.”

In contrast, native Phragmites are generally shorter, grow in less dense clusters and have other plants growing amongst them. Invasive Phragmites, as detailed above, don’t like to share space or resources in this manner. The stalks of native species tend to also be more reddish-brown in colour and the seedheads don’t contain the same concentration of seeds as the invasive version does.

In a report first released in 2011 and updated in 2021, the Ontario Invasive Plant Council ( has determined there are ways to manage/mitigate phragmite infiltration:

For Dry-land Management Sites – applying herbicides or selective cutting/spading on land.

For Wet Management Sites – flooding the impacted area, as well as selective cutting/spading of the plants in the water, which leads to them essentially ‘drowning.’

Techniques to be used in combination with other management options include - cultural control, mulching or prescribed burning.

According to the report, so-called cultural control “uses re-vegetation to encourage the growth of native or ground covering plant species with the intention of providing resistance to the invasion of unwanted plants species. The use of native grasses and flowering forbs is increasing with the growing availability of native seed mixes and the recognition that native species are important in the restoration of biological diversity. Introducing competitive native grasses, forbs, and woody plants to diminish the spread and seed germination of Phragmites is under continuous research and is showing promising results.

In the conclusion of the report, the Ontario Invasive Species Council gets right to the heart of the matter and provides the motivation behind Cataraqui Conservation’s efforts to bring awareness of invasive Phragmites.

“Planning and goal setting are essential components for any individual or group seeking to manage Phragmites. Impacts on wildlife and plant communities including species at risk must also be considered. Research and new management strategies are continuing to strive for new solutions and options to assist organizations in Phragmites management. Managing Phragmites is a long-term commitment that requires significant resources and partnership, however, the benefits from maintaining habitat are well worth the effort.”

Subsequent articles will examine, in more detail, some of the strategies being implemented and what residents/property owners can do to help stem the tide of invasive Phragmites not only in their own area, but throughout the Cataraqui Region and beyond.

For information on Cataraqui Conservation's Summer 2023 Phragmites Removal Assistance Program and other aquatic invasive species visit