Phragmites are the common reed known scientifically as Phragmites australis. They are found worldwide in Europe, North America, Asia, Africa, and Australia. While primarily located in coastal marsh areas and wetlands, the reed is also found inland in areas such as the mid-western United States. Phragmites spread using a rhizome root system, and are frequently used as a habitat for many varied species of birds. The plant can reach heights of 19.6 feet (6 m), and the invasive nature of its root structure means it is often thought of as a nuisance, and is sometimes removed so it does not interfere with other plant life and shorelines.
Originally thought to be introduced to North America from Europe, there is now evidence that some forms of the plant are native to North America. Phragmites can live in both clear and brackish water, and grow in expansive plots connected by a shared root system known as reed beds. The grazing of pasture animals can serve as a limiting function of the size of the beds, which, when left unchecked, can grow to sizes reaching almost half a square mile (1 km).
Phragmites flower in the middle of the summer, and grow silky hair like spikelets. Though the reed spreads mostly through its rhizome root structure, the spread of the flowers by wind serves to move the plant to new areas. Conversely, the thick root system of the plant allows it to move out quickly within its current space, overtaking other foliage in a given area. The invasiveness of Phragmites mean it is often removed as result of blocking coastal access and destroying surrounding plant life. Given the tenaciousness of its root structure, the plant may need to be removed using multiple burnings and chemical treatments, such as herbicides.
Many species of birds use Phragmites as a habitat for winter migration, nesting, and breeding. There exists some concern that the frequent removal of the reeds may displace the birds and threaten their survival. Several species of heron, such as the Green Heron, use the reed for nesting, while types of geese, such as the Canadian Goose, use it for breeding. Other species of birds that live within the reeds include the Mallard duck, Tree Swallows, and the Marsh Wren.
While no longer a common practice, Phragmites were used in Britain as reeds for thatching the roofs of houses and other structures. Historically, the reed has also been used to make baskets, mats, and even spears. It is still used today in some forms of water treatment filtering, where the roots of the plant are used to treat and filter out gray water for irrigation purposes.