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Common Reed

Phragmites australis

Summary 6

Phragmites australis, known as the common reed, is a species of flowering plant in the grass family Poaceae. It is a wetland grass that can grow up to 20 feet (6 metres) tall and has a cosmopolitan distribution worldwide.

Short Description 7

Common reed is a tall grass that can grow up to 6 m (20 ft). The stems are hollow, golden-colored, topped by large, dark purple feathery flower spikes that fade to brown as the structure containing the flowers (the spikelets) grow bristles.

Source: EwA Invasive Pocket Fieldguide | © Earthwise Aware

Description 8

Phragmites australis commonly forms extensive stands (known as reed beds), which may be as much as 1 square kilometre (0.39 square miles) or more in extent. Where conditions are suitable it can also spread at 5 metres (16 feet) or more per year by horizontal runners, which put down roots at regular intervals. It can grow in damp ground, in standing water up to 1 m (3 ft 3 in) or so deep, or even as a floating mat. The erect stems grow to 2–4 m (6+1⁄2–13 ft) tall,[1] with the tallest plants growing in areas with hot summers and fertile growing conditions.

The leaves are 18–60 centimetres (7–23+1⁄2 in) long and 1–6 cm (1⁄2–2+1⁄4 in) broad. The flowers are produced in late summer in a dense, dark purple panicle, about 15–40 cm (6–15+1⁄2 in) long. Later the numerous long, narrow, sharp pointed spikelets appear greyer due to the growth of long, silky hairs. These eventually help disperse the minute seeds.

Invasiveness 8

In North America, the status of Phragmites australis is a source of confusion and debate. It is commonly considered a non-native and often invasive species, introduced from Europe in the 1800s. However, there is evidence of the existence of Phragmites as a native plant in North America long before European colonization of the continent. The North American native subspecies, P. a. subsp. americanus (sometimes considered a separate species, P. americanus), is markedly less vigorous than European forms. The expansion of Phragmites in North America is due to the more vigorous, but similar-looking European subsp. australis.

Phragmites australis subsp. australis outcompetes native vegetation and lowers the local plant biodiversity. It forms dense thickets of vegetation that are unsuitable habitat for native fauna. It displaces native plants species such as wild rice, cattails, and native orchids. Phragmites has a high above ground biomass that blocks light to other plants allowing areas to turn into Phragmitesmonoculture very quickly. Decomposing Phragmites increases the rate of marsh accretion more rapidly than would occur with native marsh vegetation.

Phragmites australis subsp. australis is causing serious problems for many other North American hydrophyte wetland plants, including the native P. australis subsp. americanus. Gallic acid released by phragmites is degraded by ultraviolet light to produce mesoxalic acid, effectively hitting susceptible plants and seedlings with two harmful toxins. Phragmites is so difficult to control that one of the most effective methods of eradicating the plant is to burn it over 2–3 seasons. The roots grow so deep and strong that one burn is not enough. Ongoing research suggests that goats could be effectively used to control the species.

🚧 Control Methods (EwA Content Development in Progress) 7

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Sources and Credits

  1. (c) Joe MacIndewar, some rights reserved (CC BY-NC), uploaded by Joe MacIndewar, https://www.inaturalist.org/observations/65714162
  2. (c) Daniel Onea, some rights reserved (CC BY-NC), uploaded by Daniel Onea, https://www.inaturalist.org/observations/17324190
  3. (c) Claire O'Neill, some rights reserved (CC BY-NC), uploaded by Claire O'Neill, https://www.inaturalist.org/observations/136974448
  4. (c) Claire O'Neill, some rights reserved (CC BY-NC), uploaded by Claire O'Neill, https://www.inaturalist.org/observations/87290378
  5. (c) Liz Meyer, some rights reserved (CC BY-NC), uploaded by Liz Meyer, https://www.inaturalist.org/observations/30869613
  6. (c) Wikipedia, some rights reserved (CC BY-SA), https://en.wikipedia.org/wiki/Phragmites_australis
  7. (c) Claire O'Neill, some rights reserved (CC BY-SA)
  8. Adapted by Claire O'Neill from a work by (c) Wikipedia, some rights reserved (CC BY-SA), https://en.wikipedia.org/wiki/Phragmites_australis

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