Phragmites reproduces by dispersing seeds, by roots via rhizomes, or by stolon fragments. Dispersal can be natural through water, air, or animal movement, as well as through human actions and equipment such as through the horticultural trade, construction, boats, trailers, or ATVs.

Seeds: Phragmites produces up to 2,000 seeds per seed head per year. While seed viability is variable, recent research has revealed phragmites spread to new areas mostly through seeds.

Rhizomes: Rhizomes are underground stems that are connected to the parent plant that are capable of growing new plants. Broken rhizome fragments may be washed down rivers and shorelines to new sites or through heavy equipment and construction, where they can establish.

Stolons: Stolons are stems that are connected to the parent plant that grow along the soil surface and can form new plants. These contribute to the spread of Phragmites within an area.

More development in recent years has increased the number of roads we have which has increased our level of landscape connectivity, facilitating the transport of seeds, stolons and rhizomes to non-invaded areas. Roadsides are often disturbed environments with high contaminants, which promote Phragmites establishment.

Human induced changes to wetlands such as shoreline development may also promote an invasion of Phragmites, leaving large open spaces, free of competitors.

Some people may transport Phragmites from the roadside to their garden, realizing later its invasiveness. It is also often used for duck blinds for hunting.