Imperata cylindrica

{{Short description|Species of grass}} {{Speciesbox | name = Cogongrass | image = Imperata cylindrica tigaya colony.jpg | image_caption = ''Imperata cylindrica'' in Susami, Wakayama, Japan with mature seed heads | genus = Imperata | species = cylindrica | authority = (L.) P.Beauv.<ref name=GRIN>{{GRIN | 19864 | ''Imperata cylindrica'' | access-date = 2016-04-03 }}</ref> | synonyms_ref= <ref name="POWO">{{cite web |title= ''Imperata cylindrica'' (L.) Raeusch. |year=2024 |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30138371-2#synonyms |website=Plants of the World Online |publisher=Royal Botanic Gardens, Kew |access-date= 3 June 2024}}</ref> | synonyms = {{Collapsible list | * ''Calamagrostis lagurus'' (L.) Koeler * ''Imperata allang'' Jungh. * ''Imperata angolensis'' Fritsch * ''Imperata arundinacea'' Cirillo * ''Imperata dinteri'' Pilg. * ''Imperata filifolia'' Nees ''ex'' Steud. * ''Imperata koenigii'' (Retz.) P.Beauv. * ''Imperata laguroides'' (Pourr.) J.Roux * ''Imperata latifolia'' (Hook.f.) L.Liu * ''Imperata pedicellata'' Steud. * ''Imperata praecoquis'' Honda * ''Imperata robustior'' A.Chev. * ''Imperata sieberi'' Opiz * ''Imperata thunbergii'' P.Beauv. * ''Lagurus cylindricus'' L. * ''Saccharum cylindricum'' (L.) Lam. * ''Saccharum europeaum'' Pers. * ''Saccharum koenigii'' Retz. * ''Saccharum laguroides'' Pourr. * ''Saccharum sisca'' Cav. * ''Saccharum spicatum'' J.Presl * ''Saccharum thunbergii'' Retz. }} }}

'''''Imperata cylindrica''''' (commonly known as '''cogongrass''' {{IPAc-en|k|oʊ|ˈ|ɡ|oʊ|n}} or '''kunai grass''' {{IPAc-en|ˈ|k|uː|n|aɪ}}<ref name=GRIN/><ref name="CABI">{{cite journal|url=http://www.cabi.org/isc/datasheet/28580|title=''Imperata cylindrica'' (cogongrass)|date=2008 |publisher=Centre for Agriculture and Bioscience International (CABI)|doi=10.1079/cabicompendium.28580 |access-date=November 16, 2016 |last1=Parker |first1=C. |work=CABI Compendium |volume=CABI Compendium |article-number=28580 |doi-access=free }}</ref>) is a species of perennial rhizomatous grass native to tropical and subtropical Asia, Micronesia, Melanesia, Australia, Africa, and Southern Europe. It has also been introduced to Latin America, the Caribbean, and the Southeastern United States. It is a highly flammable pyrophyte, and can spread rapidly by colonizing disturbed areas and encouraging more frequent wildfires.<ref name="Pillion">{{cite web |last1=Pillion |first1=Dennis |title=This 'vicious' invasive plant burns hot enough to kill trees and stabs them with its roots |url=https://www.al.com/news/2017/08/this_invasive_plant_is_sending.html |website=Alabama Local |date=13 August 2017 |access-date=3 July 2019}}</ref>

== Common names ==

The species is most commonly known in English as "cogongrass" (also "cogon grass"),<ref name="CABI"/> from Spanish ''cogón'', from the Tagalog and Visayan ''kugon''.<ref>{{cite web|url=http://www.merriam-webster.com/dictionary/cogon |title=Merriam-Webster Dictionary: Cogon |publisher=Merriam-webster.com |date=2018-07-19 |access-date=2018-07-26}}</ref> Other common names in English include kunai grass, blady grass, satintail, spear grass, sword grass, thatch grass, alang-alang, lalang grass, cotton wool grass, kura-kura,<ref name="CABI"/> and keri,<ref name="dja">{{Cite book |last= Djawanai |first= Stephanus |title= Ngadha Text Tradition: The Collective Mind of the Ngadha People, Flores |date=1983 |publisher= Australian National University |series= Pacific Linguistics Series D – No. 55 |location= Canberra |page= 25 |doi= 10.15144/PL-D55 |hdl= 1885/145062 |isbn= 978-0-85883-283-1 |hdl-access= free}}</ref> among other names.

== Taxonomy == ''Imperata cylindrica'' was first described by Linnaeus in 1759 under the basionym ''Lagurus cylindricus''.<ref name="linn">{{Cite web |title=Imperata cylindrica - Species Details |url=http://florida.plantatlas.usf.edu/plant.aspx?id=1407 |access-date=2024-05-27 |website=Atlas of Florida Plants}}</ref> They were renamed by the French entomologist and botanist Palisot de Beauvois to the current accepted name of ''Imperata cylindrica''.

== Description == Cogongrass grows from {{convert|0.2-3|m|ft|abbr=on|frac=2}} tall, its stalk is firm and has nodes covered with long white hairs.<ref name="si"/><ref name="FoS"/> Each clump that grows shares an extensive rhizome network, the biomass of which accounts for 60% of the total biomass of the plant. They can penetrate up to {{convert|1.2|m|ft|abbr=on|frac=2}} deep, but {{convert|0.4|m|ft|abbr=on|frac=2}} is typical in sandy soil.<ref name="si">{{cite web |url=http://www.sms.si.edu/irlspec/Imperata_cylindrica.htm |title=Imperata cylindrica |website= Smithsonian Marine Station |publisher=Smithsonian Institution |access-date=31 March 2016}}</ref><ref name="Sellers">{{cite book |last1=Sellers |first1=B. A. |last2=Ferrell |first2=J. A. |last3=MacDonald |first3=G. E. |last4=Enloe |first4=S. F. |last5=Flory |first5=S. L. |chapter=Cogongrass (''Imperata cylindrica'') Biology, Ecology, and Management in Florida Grazing Lands |date=2002 |publisher=Agronomy Department, UF/IFAS Extensio |title=Publication #SS-AGR-52 |url=https://edis.ifas.ufl.edu/wg202}}</ref>

The leaves are about 2 cm wide in average and {{Convert|12–80|cm|frac=2}} in length<ref name="FoS">{{cite book |last1=Middleton |first1=D.J. |last2=Leong-Škorničková |first2=J. |last3=Lindsay |first3=S. |year=2019 |title=Flora of Singapore |volume=7: Poales |pages=360–362 |publisher=National Parks Board |isbn= 978-981-14-3024-4}}</ref> near the base of the plant and narrow to a sharp point at the top; the margins are finely toothed and are embedded with sharp silica crystals. The main vein is a lighter colour than the rest of the leaf and tends to be nearer to one side of the leaf. The upper surface is hairy near the base of the plant while the underside is usually hairless.<ref name="si"/>

Its flowers small and gathered on pedicels 0.5–3 mm long from narrow panicles slightly above its stalks that grow tall as high as 28 cm.<ref name="FoS"/>

{{gallery|mode=packed |File:Imperata cylindrica Bukidnon, Philippines.jpg|''Imperata cylindrica'' on a mountainside in Bukidnon, Philippines |Image:Imperata cylindrica seeds.jpg|Seeds }}

=== Phytochemistry === The plant contains the triterpenoids arundoin, cylindrin and fernenol.<ref>The structures of arundoin, cylindrin and fernenol : Triterpenoids of fernane and arborane groups of imperata cylindrica var. koenigii. K. Nishimoto, M. Ito and S. Natori, Tetrahedron, 1968, Volume 24, Issue 2, Pages 735–752, {{doi|10.1016/0040-4020(68)88023-8}}</ref>

== Ecology ==

=== As a weed === The plant has become naturalized in the Americas, Northern Asia, Europe and Africa in addition to many islands and is listed as an invasive weed in some areas. In the United States it survives best in the Southeast (and, according to a 2003 survey, has overtaken more acreage in that region than the notorious kudzu),<ref>{{Cite web |title=Aggressive weed becoming a menace worse than kudzu, UF researcher says |url=http://news.ufl.edu/2007/07/05/cogongrass/ |archive-url=https://web.archive.org/web/20080517004050/http://news.ufl.edu/2007/07/05/cogongrass/ |archive-date=2008-05-17}}</ref> but has been reported to exist as far north as West Virginia and Oregon. Worldwide it has been observed from 45°N to 45°S. It grows on wet lands, dry lands, areas of high salinity, organic soils, clay soils, and sandy soils of pH from 4.0 to 7.5. It prefers full sun but will tolerate some shade. In Florida, ''I.{{Nbsp}}cylindrica'' is found in areas where the soil has been disturbed, such as roadsides, building sites, timber harvesting areas, and borrow pits. It is able to invade both moist and dry upland pine forests. Once established it often forms dense monocultures.<ref>{{cite web |title=Cogongrass |url=http://www.freshfromflorida.com/Divisions-Offices/Florida-Forest-Service/Our-Forests/Forest-Health/Invasive-Non-native-Plants/Cogon-Grass |archive-url=https://web.archive.org/web/20131202222701/http://www.freshfromflorida.com/Divisions-Offices/Florida-Forest-Service/Our-Forests/Forest-Health/Invasive-Non-native-Plants/Cogon-Grass |archive-date=2013-12-02 |access-date=2013-11-25 |work=Invasive Non-native Plants |publisher=Florida Department of Agriculture and Consumer Services}}</ref>

In addition to outcompeting species for resources, the grass also exhibits allelopathic tendencies. The chemicals it releases as well as the dense mat of vegetation that usually accompanies a cogongrass invasion gives it an advantage over indigenous plants.<ref name=":0">{{cite web |last=Long |first=Elizabeth A. |title=Identification and Control Methods for Cogongrass in Tennessee |url=http://tninvasives.org/PB1792.pdf |archive-url=https://web.archive.org/web/20160412134106/http://tninvasives.org/PB1792.pdf |archive-date=April 12, 2016 |access-date=March 30, 2016 |website=Tennessee invasives |publisher=University of Tennessee}}</ref>

It spreads both through small seeds, which are easily carried by the wind, and rhizomes which can be transported by tilling equipment and in soil transport.

In the Southeastern U.S., state governments have various eradication efforts in place, and deliberate propagation is prohibited by some authorities.<ref>{{Cite web |last=Mazhukhina |first=Karina |date=August 27, 2021 |title=Avoid this plant at your local garden center. It's 'world's most invasive weed' |url=https://www.newsobserver.com/news/nation-world/national/article253802483.html}}</ref> Cogongrass came to the Southeastern U.S. in the early 1900s as shipping material in crates.<ref name="Dickens-1974">{{cite journal |last=Dickens |first=Ray |year=1974 |title=Cogongrass in Alabama after Sixty Years |url=http://www.cambridge.org/core/journals/weed-science/article/cogongrass-in-alabama-after-sixty-years/A761469F65AD53CB973E4C2AE740D2E8 |journal=Weed Science |publisher=Cambridge University Press (CUP) |volume=22 |issue=2 |pages=177–179 |doi=10.1017/s004317450003681x |bibcode=1974WeedS..22..177D |issn=0043-1745 |s2cid=86848569|url-access=subscription }}</ref> Before it was named an invasive species in the area, it was cultivated for fodder for livestock and erosion control.<ref name="Hubbard-1944">{{cite book |last1=Hubbard |first1=C.E. |url=https://books.google.com/books?id=DRVGAAAAYAAJ |title=Imperata cylindrica: Taxonomy, distribution, economic significance and control |publisher=Imperial Forestry Bureau & Imperial Bureau of Pastures and Forage Crops |year=1944 |series=Imperial Agricultural Bureaux Joint Publication No. 7 |place=Oxford & Aberystwyth, U.K.}}</ref> It failed to prevent erosion because of how weedy it was, and animals would not eat it as fodder.<ref>{{Cite web |title=Cogongrass Resources | National Invasive Species Information Center |url=https://www.invasivespeciesinfo.gov/terrestrial/plants/cogongrass/resources#:~:text=If%20you%20suspect%20you%20have,come%20do%20a%20site%20visit.}}</ref> It is now listed as a Federal Noxious Weed in some Southeastern states<ref name="Prince-2018">{{cite web |title=Cogongrass biology and management in the southeastern U.S. University of Florida, Southern Regional Extension Forestry, 2018 Candice Prince, Gregory MacDonald, Stephen Enloe, and David Coyle |url=http://southernforesthealth.net/plants/cogongrass/cogongrass-biology-and-management-in-the-southeastern-u.s}}</ref> and Arkansas.<ref name="UAEX">{{cite web |title=Arkansas Invasive Pests {{pipe}} Cogongrass |url=http://www.uaex.edu/environment-nature/ar-invasives/invasive-plants/cogongrass.aspx |archive-url=https://web.archive.org/web/20210918231718/https://www.uaex.edu/environment-nature/ar-invasives/invasive-plants/cogongrass.aspx |archive-date=2021-09-18 |access-date=2020-10-30}}</ref> In Mississippi it is mostly concentrated in the south of the state.<ref name="Mississippi-2020-12-16" />

Control is typically by the use of herbicides. Currently, the most effective herbicides used to control growth are glyphosate and imazapyr.<ref>{{Cite journal |last1=Dozier |first1=Hallie |last2=Gaffney |first2=James F. |last3=McDonald |first3=Sandra K. |last4=Johnson |first4=Eric R. R. L. |last5=Shilling |first5=Donn G. |date=1998-01-01 |title=Cogongrass in the United States: History, Ecology, Impacts, and Management |journal=Weed Technology |volume=12 |issue=4 |pages=737–743 |doi=10.1017/S0890037X0004464X |jstor=3989097 |bibcode=1998WeedT..12..737D |s2cid=55181258}}</ref> Burnoff is seldom successful since the grass burns at a high temperature, causing heat damage to trees which would ordinarily be undamaged by a controlled burn; it also recovers from a burn quickly. Quarantine and extermination of this plant is especially difficult because cogongrass establishes root systems as deep as four feet, and regrowth can be triggered by rhizome segments as small as one inch.<ref name=":0" />

Cogongrass is difficult to contain mainly because it is highly adaptive to harsher environments, establishing itself on soils low in fertility. The grass can also grow on sand and clay. It is not eaten by many species of animal, further contributing to containment difficulties. The grass tends to be averse to dense shade, but reports indicate more shade-tolerant strains are developing.<ref>{{cite web |title=Imperata cylindrica {{!}} UF/IFAS Center for Aquatic and Invasive Plants |url=https://plants.ifas.ufl.edu/plant-directory/imperata-cylindrica/ |access-date=2016-03-31 |website=plants.ifas.ufl.edu |archive-date=2021-12-12 |archive-url=https://web.archive.org/web/20211212165435/https://plants.ifas.ufl.edu/plant-directory/imperata-cylindrica/ }}</ref>{{Clarify timeframe|date=July 2021}}

The legume vine ''Mucuna pruriens'' is used in the countries of Benin and Vietnam as a biological control for ''Imperata cylindrica''.<ref>{{cite web |title=Factsheet - ''Mucuna pruriens'' |url=http://www.tropicalforages.info/key/Forages/Media/Html/Mucuna_pruriens.htm |archive-url=https://web.archive.org/web/20080515210229/http://www.tropicalforages.info/key/Forages/Media/Html/Mucuna_pruriens.htm |archive-date=2008-05-15 |access-date=2008-05-21 |publisher=www.tropicalforages.info}}</ref>

=== Flammability === [[Image:Kunai on fire.JPG|thumb|right|Green cogongrass on fire in Papua New Guinea.]]

Cogongrass is a pyrophyte. It is highly flammable, even when still apparently green,<ref>{{Cite web |url=http://www.fao.org/ag/AGP/agpc/doc/gbase/DATA/pf000261.htm |title=Species Description: Imperata cylindrica (L.) Beauv. |access-date=2010-12-16 |archive-url=https://web.archive.org/web/20100728114328/http://www.fao.org/ag/AGP/AGPC/doc/GBASE/data/pf000261.htm |archive-date=2010-07-28 }}</ref> particularly in tropical climates. It is not uncommon to see hillsides of cogongrass on fire.<ref>{{cite web |url=http://www.tropicalgrasslands.asn.au/Tropical%20Grasslands%20Journal%20archive/titles%20only/early%20vol%20pdfs/Vol%2011%20No%203/Vol%2011%20%5B3%5D%20Paper%206%20PNG.pdf |title='Establishment of Stylo (''Stylosanthes Guianensis'') in Kunai (''Imperata cylindrica'') pastures and its Effect of Dry Matter Yield and Animal Production in the Markham Valley, Papua New Guinea by P.A. Chadhokar |access-date=2018-07-26 |archive-date=2018-03-30 |archive-url=https://web.archive.org/web/20180330232924/http://tropicalgrasslands.asn.au/Tropical%20Grasslands%20Journal%20archive/titles%20only/early%20vol%20pdfs/Vol%2011%20No%203/Vol%2011%20%5B3%5D%20Paper%206%20PNG.pdf }}</ref><ref>{{cite web |url=http://www.postcourier.com.pg/20090907/news03.htm |title=Fire leaves 20 without shelter |publisher=Postcourier.com.pg |access-date=2018-07-26 |archive-url=https://web.archive.org/web/20120308224938/http://www.postcourier.com.pg/20090907/news03.htm |archive-date=2012-03-08 }}</ref> Cogongrass depends on regular fires to spread and maintain ecological dominance. Because of its density and high biomass, cogongrass provides a very high fuel load, enabling wildfires to burn faster, higher, and much hotter. This is hot enough to kill most competing plants, including trees. After a fire, cogongrass will recolonize the area using their rhizome network which was unaffected by the fire.<ref name="Pillion"/><ref name="Stocker">{{cite book |last1=Stocker |first1=Randall |last2=Hupp |first2=Karen V.S. |title=Wildland Fire in Ecosystems: Fire and nonnative invasive plants |date=2008 |publisher=Rocky Mountain Research Station, Forest Service, USDA |chapter=Fire and Nonnative Invasive Plants in the Southeast Bioregion |isbn=978-0-16-081465-5 |page=103 |chapter-url=https://books.google.com/books?id=kGarZgNvi2AC&pg=PA103}}</ref><ref name="Lippincott">{{cite journal |last1=Lippincott |first1=C.L. |title=Effects of ''Imperata cylindrica'' (L.) Beauv. (Cogongrass) invasion on fire regime in Florida sandhill (USA) |journal=Natural Areas Journal |date=2000 |volume=20 |issue=2 |pages=140–149}}</ref><ref name="Sellers"/>

==Uses== [[File:Imperata cylindrica 'Red Baron' Kruidtuin Leuven.jpg|thumb|A Japanese bloodgrass cultivar, ''Imperata cylindrica'' 'Red Baron', grown as an ornamental]]

It is regarded as an excellent plant for thatching the roofs of traditional homes throughout south-east Asia, and is even grown as a crop for this purpose.<ref name="dja"/><ref>{{cite book |last1=Holm |first1=LeRoy G. |last2=Plucknett |first2=Donald L. |last3=Pancho |first3=Juan V. |last4=Herberger |first4=James P. |title=The World's Worst Weeds: distribution and biology |date=1977 |page=70|publisher=University Press of Hawaii |location=Honolulu |isbn=0-8248-0295-0}}</ref>

It is planted extensively for ground cover and soil stabilization near beach areas and other areas subject to erosion. Other uses include paper-making, thatching and weaving into mats and bags. It is used in traditional Chinese medicine.<ref>{{cite web|url=http://www.acupuncturetoday.com/herbcentral/imperata.php|title=Imperata|publisher=Acupuncturetoday - traditional Chinese medicine (tcm)|access-date=22 Dec 2014}}</ref>

A number of cultivars have been selected for garden use as ornamental plants, including the red-leaved 'Red Baron', also known as Japanese blood grass.

Young inflorescences and shoots may be eaten cooked, and the roots contain starch and sugars.<ref>{{cite web|url=http://www.pfaf.org/database/plants.php?Imperata+cylindrica|title=''Imperata cylindrica''|website=PFAF|access-date=2016-03-31}}</ref>

== In culture == A common expression in the Philippines is '''''ningas kugon''''' ('cogon brush fire'). It is a figure of speech for quitters, specifically people who show a fervent interest in a new project but lose interest quickly, in reference to the propensity of cogongrass to catch fire and burn out quickly.<ref>{{Cite web |title=Filipino Culture: What is Ningas Cogon |url=http://www.dailyrandomsites.com/what-is-ningas-cogon/ |archive-url=https://web.archive.org/web/20110115142541/http://www.dailyrandomsites.com/what-is-ningas-cogon/ |archive-date=2011-01-15 |access-date=2010-12-16}}</ref> The concept is similar to, but distinct from, procrastination.<ref>{{cite web |date=22 June 2022 |title=Little-Known Power of Ningas Kugon to Create Breakthroughs |url=https://jefmenguin.com/ningas-kugon/#:~:text=that%20TV%20interview.-,What%20is%20ningas%20kugon%3F,upon%20reaching%20the%20first%20obstacle}}</ref>

== References == {{Reflist|40em|refs= <ref name="Mississippi-2020-12-16">{{cite web | author=Associated Press | title=Cogongrass: Mississippi fights to control one of world's most invasive weeds | website=Al.com | date=2020-12-16 | url=http://www.al.com/news/2020/12/cogongrass-mississippi-fights-to-control-one-of-worlds-most-invasive-weeds.html | access-date=2021-01-02}}</ref> }}

== External links == {{Commons category|position=left}} * [http://www.fao.org/3/y5031e/y5031e08.htm Characteristics and management of ''Imperata cylindrica'' (L.) Raeuschel in smallholder farms in developing countries], Food and Agriculture Organization of the United Nations * [http://www.pfaf.org/database/plants.php?Imperata+cylindrica PFAF.org: Cultivation and edible/medicinal uses of ''Imperata cylindrica''] * [https://www.delta-intkey.com/grass/www/imperata.htm ''Imperata cylindrica''], Grass Genera of the World * [https://plants.usda.gov/java/profile?symbol=IMCY USDA Plants Profile for ''Imperata cylindrica'' (cogongrass)] — ''invasive species''. * [https://www.invasive.org/alien/fact/imcy1.htm Least Wanted: Cogon Grass], Plant Conservation Alliance's Alien Plant Working Group * [http://edepot.wur.nl/121366 WageningenUR.nl: "From Imperata cylindrica Grasslands to productive Agroforestry"] — ''Murniati PhD thesis (2002)''. * [https://www.invasivespeciesinfo.gov/terrestrial/plants/cogongrass Cogongrass ''Imperata cylindrica'' Species Profile] — information and control resources from the National Invasive Species Information Center, U.S. Department of Agriculture National Agricultural Library * [https://keyapa.com/grass/imperata_cylindrica.htm ''Imperata cylindrica'' in Guide to Invasive and Hegemonic Grasses] * [http://www.uaex.edu/environment-nature/ar-invasives/invasive-plants/cogongrass.aspx Arkansas Invasive Pests {{pipe}} Cogongrass] {{Webarchive|url=https://web.archive.org/web/20210918231718/https://www.uaex.edu/environment-nature/ar-invasives/invasive-plants/cogongrass.aspx |date=2021-09-18 }} * {{cite web | title=Cogongrass, Imperata cylindrica (L.) Beauv. in the Southeast U.S. | website=Cogongrass.org | url=http://www.cogongrass.org/ | access-date=2021-01-02 | publisher=Center for Invasive Species and Ecosystem Health}} * {{cite web | title=Cogongrass Distribution | website=Cogongrass.org | url=http://www.cogongrass.org/distribution/ | access-date=2021-01-02 | publisher=Center for Invasive Species and Ecosystem Health}}

Category:Andropogoneae Category:Grasses of Africa Category:Grasses of Asia Category:Grasses of Europe Category:Grasses of Oceania Category:Plants described in 1759 Category:Taxa named by Palisot de Beauvois Category:Ornamental grass