Invasive Phragmites has been identified as Canada’s worst invasive species by Canada Food Inspection Agency. It is extremely effective in outcompeting native species such as cattails (Typha sp.) to rapidly replace native plant communities with a monoculture of this invasive grass. This species can spread by seed, but often expands vegetatively via rootlike appendages called stolons (aboveground runners) and rhyzomes (belowground structures). Managing this species as early as possible is extremely important, as large populations can be quite challenging to contain and remove.
A close relative of the invasive Phragmites is also found in Ontario. The native Phragmites is technically of the same species, but considered a different haplotype. Although distinguishing between the species can be challenging for many people, some suggest that populations growing in dense patches are nearly always the invasive Phragmites. Further information regarding distinguishing the two should be consulted before management is considered.