You have probably seen this perennial grass along roadsides as a huge area of tall, lush silvery green flower heads waving in the wind. Yes, this is an invasive plant. It was introduced to North America in the 1800s and in 2005 was recognized as Canada’s worst invasive plant by Agriculture Canada. Dense stands of this grass have spread throughout Ontario threatening the habitats of the Great Lakes and inland lakes.

Invasive Phragmites, with as many as 200 stems per square metre, outcompete native plants by releasing toxins into the soil, change lake habitats for wildlife and decrease recreational activities. They can grow on shorelines, in wetlands, watercourses and roadside ditches. Despite preferring areas of standing water, the roots, which can grow up to 4 metres long, allow it to survive in drier areas. Reaching a height of 5 metres, or 15 feet, the flower heads turn brown in the fall atop brown, rough, ridged stems.

A native subspecies of Phragmites exists in Ontario too. Generally, the native version does not grow as dense, is frequently mixed with other plants and has more reddish-brown stems, yellow-green leaves and sparser seed heads.

What can you do if you think the Phragmites on your property are the invasive version? Your Lake Association has applied for a grant to help us develop a program of identification and advice in eradication. More news on that soon, we hope. A good website to consult is Ontario’s Invading Species Awareness Program at www.invadingspecies.com. Once Phragmites have been identified there are several methods of management. On dry land a herbicide can be used, although there is no herbicide permitted for use in or around water in Ontario. Another method on land involves using a spade to cut the roots, pulling up as much as possible then disposing of the plant material, in a safe manner. You can burn it once it is dry or place it in black plastic garbage bags in the sun until it is well rotted, after which it can be sent to the landfill. On wet sites selective cutting beneath the waterline can drown the plant by cutting off oxygen to the lower stems and roots. The new shoots then cannot reach the surface to get oxygen. This can be done using hand tools or amphibious cutting tools. Again, you bag the plants and leave them to decay before sending them to the landfill. Never attempt to compost invasive Phragmites as they can survive and grow in the compost. If you have been working with the plant, brush off your clothing and tools so you don’t transfer seeds to other sites.

Hopefully, you do not have this invasive grass on your property but if you find some you will be more informed on how to deal with it.

NOTE: On June 29th, FOCA will present a Phragmites webinar. Members of the BLLA are automatically members of FOCA and have access to this webinar should you wish to attend. Register by clicking here.