{{Globalize|date=March 2024}} {{Short description|Species of grass commonly known as reed}} {{Speciesbox | name = Common reed | image = Phragmites australis - NASA Tracks an Environmental Invader (48049936657).jpg | image_caption = Invasive common reed in the U.S. | status = LC | status_system = IUCN3.1 | status_ref = <ref name=IUCN>{{cite iucn |author1=Lansdown, R.V. |author2=Diop, F.N. |name-list-style=amp |year=2020 |title=''Phragmites australis'' |article-number=e.T164494A140439343 |doi=10.2305/IUCN.UK.2020-3.RLTS.T164494A140439343.en |access-date=9 March 2026}}</ref> | genus = Phragmites | species = australis | authority = (Cav.) Trin. ex Steud. | synonyms = *''Arundo australis'' <small>Cav.</small> }}

'''''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 {{convert|20|ft|0|abbr=off}} tall and has a cosmopolitan distribution worldwide.

==Description== ''Phragmites australis'' commonly forms extensive stands (known as reed beds), which can reach {{convert|1|km2|mi2|abbr=off}} or more in extent. Where conditions are suitable it can also spread at {{Convert|5|m|abbr=off}} or more per year by horizontal runners, which put down roots at regular intervals.{{citation needed|date=July 2019}} It can grow in damp ground, in standing water up to {{cvt|1|m}} deep, or even as a floating mat. The erect stems grow to {{convert|2-4|m|ft|abbr=on|frac=2}} tall,<ref name="Elias-2009">{{Cite book |last1=Elias |first1=Thomas S. |title=Edible Wild Plants: A North American Field Guide to Over 200 Natural Foods |last2=Dykeman |first2=Peter A. |publisher=Sterling |year=2009 |isbn=978-1-4027-6715-9 |location=New York |pages=129 |oclc=244766414 |orig-year=1982}}</ref> with the tallest plants growing in areas with hot summers and fertile growing conditions.

The leaves are {{Convert|18-60|cm|abbr=out|frac=2}} long and {{cvt|1-6|cm|abbr=on|frac=4}} broad. The flowers are produced in late summer in a dense, dark purple panicle, about {{Convert|15-40|cm|abbr=on|frac=2}} long.<ref name="Elias-2009" /> 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.

==Taxonomy== Recent studies have characterized morphological distinctions between the introduced and native stands of ''Phragmites australis'' in North America. The Eurasian phenotype can be distinguished from the North American phenotype by its shorter ligules of up to {{convert|0.9|mm|in|2|frac=32}} as opposed to over 1&nbsp;mm, shorter glumes of under {{cvt|3.2|mm|in|2|frac=32}} against over 3.2&nbsp;mm (although there is some overlap in this character), and in culm characteristics.{{r|saltonstall2011}}

* ''Phragmites australis'' subsp. ''americanus'' – the North American genotype has been described as a distinct species, ''Phragmites americanus''{{citation needed|date=April 2023}} * ''Phragmites australis'' subsp. ''australis'' – the Eurasian genotype * ''Phragmites australis'' subsp. ''berlandieri'' <small>(E.Fourn.) Saltonst. & Hauber</small><ref name=powo>{{cite web |work=Plants of the World Online |title=''Phragmites australis'' (Cav.) Trin. ex Steud. |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30337627-2 |publisher=Royal Botanic Gardens, Kew |access-date=18 April 2023}}</ref> * ''Phragmites australis'' subsp. ''isiacus'' <small>(Arcang.) ined.</small><ref name=powo/>

==Ecology== It is a helophyte (aquatic plant), especially common in alkaline habitats, and it also tolerates brackish water,<ref name="issg" /> and so is often found at the upper edges of estuaries and on other wetlands (such as grazing marsh) which are occasionally inundated by the sea. A study demonstrated that ''P.&nbsp;australis'' has similar greenhouse gas emissions to ''Spartina alterniflora'', a plant native to the Atlantic coast of the Americas.<ref name="AQB">{{cite journal|last1=Emery|first1=Hollie E.|last2=Fulweiler|first2=Robinson W.|date=2014|url=https://dx.doi.org/10.1016/j.aquabot.2014.01.010|title=''Spartina alterniflora'' and invasive ''Phragmites australis'' stands have similar greenhouse gas emissions in a New England marsh|journal=Aquatic Botany|volume=116|issue=5|pages=83–92|doi=10.1016/j.aquabot.2014.01.010|bibcode=2014AqBot.116...83E |url-access=subscription}}</ref> However, other studies have demonstrated that it is associated with larger methane emissions and greater carbon dioxide uptake than native New England salt marsh vegetation that occurs at higher marsh elevations.<ref name="WTL">{{cite journal |last1=Martin |first1=Rose M. |last2=Moseman-Valtierra |first2=Serena |title=Greenhouse Gas Fluxes Vary Between ''Phragmites australis'' and Native Vegetation Zones in Coastal Wetlands Along a Salinity Gradient |journal=Wetlands |date=2015 |volume=35 |issue=6 |pages=1021–1031 |doi=10.1007/s13157-015-0690-y|bibcode=2015Wetl...35.1021M |s2cid=18908597 }}</ref>

Common reed is suppressed where it is grazed regularly by livestock. Under these conditions it either grows as small shoots within the grassland sward, or it disappears altogether. In Europe, common reed is rarely invasive, except in damp grasslands where traditional grazing has been abandoned.{{citation needed|date=July 2019}}

[[File:Reedbeach edit1.JPG|thumb|center|625 px| A previously sandy beach in Hanko, Finland now dominated by ''Phragmites australis'' reeds]] ===Invasive status=== 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.{{r|invspinfo}} However, there is evidence of the existence of ''Phragmites'' as a native plant in North America long before European colonization of the continent.{{r|saltonstall2002}} The North American native subspecies, ''P.&nbsp;a.''&nbsp;subsp. ''americanus'' (sometimes considered a separate species, ''P.&nbsp;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''.{{r|catlin2011}}{{r|invspinfo}} thumb ''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.{{r|usfs}} ''Phragmites'' has a high above ground biomass that blocks light to other plants allowing areas to turn into ''Phragmites'' monoculture very quickly. Decomposing ''Phragmites'' increases the rate of marsh accretion more rapidly than would occur with native marsh vegetation.<ref name="USFWS">{{cite web|url=http://www.fws.gov/GOMCP/pdfs/phragmitesQA_factsheet.pdf|title=PHRAGMITES: Questions and Answers|website=United States Fish and Wildlife Service}}</ref>

''Phragmites australis'' subsp. ''australis'' is causing serious problems for many other North American hydrophyte wetland plants, including the native ''P.&nbsp;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.<ref name=issg>{{cite web|url=http://www.issg.org/database/species/ecology.asp?si=301&fr=1&sts=|title=GISD|first=Upane -|last=www.upane.it|website=www.issg.org}}</ref><ref>{{cite web|url=https://www.newswise.com/articles/changing-climate-may-make-super-weed-even-more-powerful|title=Changing Climate May Make 'Super Weed' Even More Powerful|website=Newswise|date=June 3, 2009|access-date=December 6, 2020|author=University of Delaware|author-link=University of Delaware}}</ref> ''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.<ref>{{cite web|url=http://stopinvasivespecies.com/phragmites/phragmites-p|title=Stop Invasive Species - Phragmites}}</ref> Ongoing research suggests that goats could be effectively used to control the species.<ref>{{cite news | url=https://www.bbc.co.uk/news/magazine-30583512 | title=The goats fighting America's plant invasion | first=Joanna | last=Jolly | date=3 December 2017 | work=BBC News}}</ref>

===Natural enemies=== Since 2017, over 80% of the beds of ''Phragmites'' in the Pass a Loutre Wildlife Management Area have been damaged by the invasive roseau cane scale (''Nipponaclerda biwakoensis''), threatening wildlife habitat throughout the affected regions of the area. While typically considered a noxious weed, in Louisiana the reed beds are considered critical to the stability of the shorelines of wetland areas and waterways of the Mississippi River Delta, and the die-off of reed beds is believed to accelerate coastal erosion.<ref name="NOLA">{{cite web|url=https://www.nola.com/news/environment/article_f804450e-d2ef-5999-b402-82499e5bc4c0.html|title=Scientists identify pest laying waste to Mississippi River Delta wetlands grass|author=Tristan Baurick|website=The Times-Picayune|date=April 14, 2017|access-date=December 6, 2020}}</ref>

==Uses== The entire plant is edible raw or cooked. The young stems can be boiled, or later on be used to make flour. The underground stems can be used but are tough, as can the seeds but they are hard to find.<ref>{{Cite book |title=The Complete Guide to Edible Wild Plants |publisher=Skyhorse Publishing |others=United States Department of the Army |year=2009 |isbn=978-1-60239-692-0 |location=New York |pages=84 |language=en-US |oclc=277203364}}</ref>

Stems can be made into eco-friendly drinking straws. Many parts of the plant can be eaten. The young shoots can be consumed raw or cooked. The hardened sap from damaged stems can be eaten fresh or toasted. The stems can be dried, ground, sifted, hydrated, and toasted like marshmallows. The seeds can be crushed, mixed with berries and water, and cooked to make a gruel. The roots can be prepared similar to those of cattails.<ref name="Elias-2009" />

Common reed is the primary source of thatch for traditional roof thatching in Europe and beyond. The plant is extensively used in phytodepuration, or natural water treatment systems, since the root hairs are excellent at filtering out impurities in waste water. It also shows excellent potential as a source of biomass.

==References== {{Reflist|refs= <ref name=catlin2011>{{cite journal|author1=Catling, P.M. |author2=Mitrow, G.l. |year=2011 |title=Major invasive alien plants of natural habitats in Canada. 1. European Common Reed (often just called Phragmites), ''Phragmites australis'' (Cav.) Trin. ex Steud. subsp. ''australis'' |journal=CBA Bulletin |volume=44 |issue=2 |pages=52–61}}</ref> <ref name=invspinfo>{{cite web |title=Common Reed |url=https://www.invasivespeciesinfo.gov/profile/common-reed |website=www.invasivespeciesinfo.gov |publisher=National Invasive Species Information Center {{!}} USDA |access-date=22 July 2020}}</ref> <ref name=saltonstall2002>{{cite journal|last=Saltonstall|first=Kristin|year=2002|title=Cryptic invasion by a non-native genotype of the common reed, ''Phragmites australis'', into North America|journal=Proceedings of the National Academy of Sciences|volume=99|issue=4|pages=2445–2449|doi=10.1073/pnas.032477999|pmid=11854535|pmc=122384|bibcode=2002PNAS...99.2445S|doi-access=free}}</ref> <ref name=saltonstall2011>{{cite journal |title=Recognition of Phragmites australis subsp. americanus (Poacaeae: Arundinoideae) in North America. Evidence from morphological and genetic analyses |last1=Saltonstall |first1=K |last2=Peterson |first2=PM|last3=Soreng |first3=RJ|date=2004 |journal=SIDA, Contributions to Botany |volume=21 |issue=2 |pages=683–692 }}</ref> <ref name=usfs>{{cite web|url=http://www.na.fs.fed.us/fhp/invasive_plants/weeds/common-reed.pdf|title=Common Reed. United States Forest Service|access-date=2020-07-12|archive-date=2016-01-27|archive-url=https://web.archive.org/web/20160127230437/http://na.fs.fed.us/fhp/invasive_plants/weeds/common-reed.pdf|url-status=dead}}</ref> }}

==Further reading== {{Scholia}} * {{cite book|url=http://www.ontarioinvasiveplants.ca/wp-content/uploads/2021/01/Phragmites-BMP-2020.pdf|archive-url=https://web.archive.org/web/20210206172159/http://www.ontarioinvasiveplants.ca/wp-content/uploads/2021/01/Phragmites-BMP-2020.pdf|archive-date=6 February 2021|title=Invasive Phragmites (''Phragmites australis'') Best Management Practices in Ontario}}

{{Taxonbar|from=Q28557}} {{Authority control}}

Category:Molinieae Category:Aquatic plants Category:Edible plants Category:Halophytes Category:Flora of Europe Category:Flora of temperate Asia Category:Flora of tropical Asia Category:Flora of Africa Category:Flora of Northern America Category:Flora of Southern America Category:Flora of Australasia Category:Flora of the Pacific Category:Taxa named by Antonio José Cavanilles