honey locust

The honey locust, Gleditsia triacanthos, can reach a height of {{cvt|20|–|30|m|ft|round=5}}.{{cite book |last1=Coombes |first1=Allen J. |title=Trees |date=2023 |publisher=Dk Publishing |location=New York |isbn=978-0-7440-7420-8 |page=137 |edition=American edition, New}} They exhibit fast growth, but live a medium life span, as long as 125 years.{{cite web |last1=Nesom |first1=Guy |title=Honey Locust |url=https://plants.usda.gov/plantguide/pdf/pg_gltr.pdf |website=Plant Guide |publisher=United States Department of Agriculture, Natural Resources Conservation Service |access-date=18 April 2020 |archive-url=https://web.archive.org/web/20200107105808/https://plants.usda.gov/plantguide/pdf/pg_gltr.pdf |archive-date=7 January 2020 |url-status=dead}} The leaves are pinnately compound on older trees but bipinnately compound on vigorous young trees. The leaflets are {{cvt|1.4|–|3.6|cm|frac=4}} long when compound and very slightly smaller when bipinnate.{{cite book |last1=Heil |first1=Kenneth D. |last2=O'Kane, Jr. |first2=Steve L. |last3=Reeves |first3=Linda Mary |last4=Clifford |first4=Arnold |title=Flora of the Four Corners Region : Vascular Plants of the San Juan River Drainage, Arizona, Colorado, New Mexico, and Utah |date=2013 |publisher=Missouri Botanical Garden |location=St. Louis, Missouri |pages=548–549 |url=https://archive.org/details/mobot31753003888887/page/n565 |access-date=29 May 2024}} The leaves are green in summer and turn yellow in autumn in shades ranging from cream and tan to golden yellow.{{cite web |title=Gleditsia triacanthos (Common Honey Locust, Honeylocust, Honey Locust, Honey Shucks Locust, Sweet Bean Tree, Sweet Locust, Thorny Locust) |url=https://plants.ces.ncsu.edu/plants/gleditsia-triacanthos/ |website=North Carolina Extension Gardener Plant Toolbox |publisher=North Carolina State University |access-date=29 May 2024 |language=en}} Honey locusts leaf out relatively late in spring, but generally slightly earlier than the black locust (Robinia pseudoacacia).{{cite web |last1=Nolan |first1=Jessica |title=Types of Locust Trees with Identification Guide and Pictures |url=https://leafyplace.com/locust-tree/ |website=Leafy Place |access-date=29 May 2024 |archive-url=https://web.archive.org/web/20231201032251/https://leafyplace.com/locust-tree/ |archive-date=1 December 2023 |language=en |date=13 January 2020 |url-status=live}}

The strongly scented flowers appear in late spring.{{cite book |last1=Day |first1=Leslie |title=Field Guide to the Street Trees of New York City |date=2011 |publisher=Johns Hopkins University Press |location=Baltimore, Maryland |isbn=978-1-4214-0151-5 |page=242 |url=https://archive.org/details/fieldguidetostre0000dayl/page/242 |access-date=29 May 2024 |language=en}} Each cluster is a raceme 3–7 centimeters long with many tiny greenish-yellow to greenish-white flowers.{{cite web |title=Gleditsia triacanthos |url=https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=a871 |website=Plant Finder |publisher=Missouri Botanical Garden |access-date=29 May 2024 |language=en}} The trees are polygamous-dioecious: many trees have only pollen producing flowers or seed producing flowers (strictly dioecious), but some will have both types of flowers in separate clusters, though usually one type will predominate.{{cite web |last1=Phillips |first1=M. |title=Honey Locust |url=https://wp.towson.edu/glenarboretum/home/honey-locust/ |website=Glen Arboretum |publisher=Towson University |access-date=29 May 2024 |language=en}}

The fruit of the honey locust is a flat pod (a legume) that matures in early autumn and is often twisted or curved. The average size of the pods is {{cvt|7|–|35|cm|0}} long and {{cvt|1.5|–|3|cm|in|frac=4}} wide. Once ripe the pod will contain as many as twenty dark brown oval seeds, each about {{cvt|2|cm|frac=2}} long. Surrounding the seeds is a soft, gooey pulp with a slightly sweet flavor.{{cite book |last1=Edlin |first1=Herbert |title=The Tree Key |date=1978 |publisher=Charles Scribner's Sons |location=New York |isbn=978-0-684-15886-0 |pages=152–153 |edition=1st American |url=https://archive.org/details/treekey0000herb/page/152 |access-date=30 May 2024 |language=en}} Pods may be produced from mid-September through mid-October in its native habitat.{{cite journal |last1=Guiden |first1=Peter W. |title=Dispersal of Honey Locust (Gleditsia triacanthos) Seeds by White-tailed Deer |journal=Ecological Restoration |date=2013 |volume=31 |issue=4 |pages=356–358 |doi=10.3368/er.31.4.356 |jstor=43443331 |url=https://www.jstor.org/stable/43443331 |access-date=30 May 2024 |language=en |issn=1543-4060}}

Honey locusts commonly have thorns {{cvt|6|–|10|cm|frac=2}} long growing out of the branches and trunk,{{cite web |last1=Breen |first1=Patrick |title=Gleditsia triacanthos |url=https://landscapeplants.oregonstate.edu/plants/gleditsia-triacanthos |website=Landscape Plants |publisher=Oregon State University |access-date=30 May 2024 |archive-url=https://web.archive.org/web/20231204100306/https://landscapeplants.oregonstate.edu/plants/gleditsia-triacanthos |archive-date=4 December 2023 |language=en |url-status=live}} some reaching lengths of {{cvt|20|cm|0}}; these may be single, or branched into several points, and commonly form dense clusters. The thorns are modified branches and occasionally sprout leaves. Thornless forms are occasionally found growing wild and are commonly available as nursery plants.

File:HoneyLocustThorn.JPG|Detail of thorns

File:Honey Locust Tree Thorns in Kansas.jpg|Honey locust tree thorns in Kansas

File:Gleditsia triacanthos Flower HW1.jpg|Detail of flowers

File:2014-10-11 12 49 16 Honey Locust foliage during autumn in Elko, Nevada.JPG|Autumn leaf color

File:Honeylocust fruits.jpg|Mature honeylocust fruits

File:Old growth honeylocust tree.jpg|Old growth honeylocust tree in Tennessee, US, 1941

Honey locust was given its scientific name of Gleditsia triacanthos by Carl Linnaeus in 1753 in his book Species Plantarum. Its taxonomic history is quite complex with a total of {{table row counter|id=synonyms}} names that are taxonomic synonyms as of 2024 including five botanical forms, fourteen varieties, and twenty-two species. Included in its synonyms by Plants of the World Online, World Flora Online,{{Cite WFO |title=Gleditsia triacanthos L. |id=0000168133 |access-date=1 June 2024}} and the USDA Natural Resources Conservation Service PLANTS database is the subordinate taxon Gleditsia triacanthos var. inermis.{{cite usda plants|symbol=GLTR |title=Gleditsia triacanthos |date=1 June 2024}} However, this scientific name is still found in gardening websites and books to distinguish thornless trees.{{cite web |title=Gleditsia triacanthos var. inermis (Honeylocust, Honey Locust, Thornless Common Honeylocust, Thornless Honey Locust) |url=https://plants.ces.ncsu.edu/plants/gleditsia-triacanthos-var-inermis/ |website=North Carolina Extension Gardener Plant Toolbox |publisher=North Carolina State University |access-date=1 June 2024 |archive-url=https://web.archive.org/web/20240217045226/https://plants.ces.ncsu.edu/plants/gleditsia-triacanthos-var-inermis/ |archive-date=17 February 2024 |language=en |url-status=live}}{{cite book |last1=Keys |first1=Andrew |title=Growing the Northeast garden |date=2015 |publisher=Timber Press |location=Portland, Oregon |isbn=978-1-60469-448-2 |page=48 |url=https://archive.org/details/growingnortheast0000keys/page/48 |access-date=1 June 2024 |language=en}}

Hybridization of honey locust with water locust (Gleditsia aquatica) has been reported.{{Cite journal |last=Schneck |first=J. |title=Hybridization in the Honey Locust |date=1904 |url=https://www.jstor.org/stable/43476409 |journal=The Plant World |volume=7 |issue=10 |pages=252–253 |jstor=43476409 |issn=0096-8307}}{{Cite web|last=Sullivan |first=J. |url=http://www.fs.fed.us/database/feis/plants/tree/gletri/all.html |title=Gleditsia triacanthos |date=1994 |access-date=1 June 2024 |website=U.S. Forest Service |publisher=U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory}}

The genus Gleditsia is named in honor of Johann Gottlieb Gleditsch, the director of what has become the Berlin Botanical Garden and Botanical Museum. The species name is derived from Greek and means "three thorns". The common name most often used for the species is "honey locust".{{cite book |last1=Quattrocchi |first1=Umberto |title=CRC World Dictionary of Plant Names : Common Names, Scientific Names, Eponyms, Synonyms, and Etymology |date=2000 |publisher=CRC Press |location=Boca Raton, Florida |isbn=978-0-8493-2673-8 |page=1084 |language=en}} This name comes from the slightly sweet pulp that surrounds the seeds in the tree's pods and their resemblance to the pods of the carob or "locust tree" from the middle east.{{cite book |last1=Harris |first1=Esmond |last2=Harris |first2=Jeanette |title=Trees and Shrubs of Britain |date=1989 |publisher=The Reader's Digest Association Limited |location=London |isbn=0-276-00218-0 |page=175 |edition=Revised |url=https://archive.org/details/bwb_KR-501-245/page/175/ |access-date=3 June 2024 |language=en}} Honey locust is also used for the genus as a whole or for other species in it. The first recorded use of the name was in 1709 by John Lawson in his account A New Voyage to Carolina.{{Cite OED|Honey Locust, N|6008132924}} In the late 1800s honey locust was sometimes used as an alternate name in localized areas for other species such as for mesquit (Prosopis juliflora) in Texas and New Mexico, for black locust (Robinia pseudoacacia) in Minnesota, and for clammy locust (Robinia viscosa) in New York and New Jersey.{{cite book |last1=Sudworth |first1=George Bishop |title=Nomenclature of the Arborescent Flora of the United States |date=1897 |publisher=Department of Agriculture, Forestry Division |location=Washington, D.C. |pages=252, 258, 262 |url=https://archive.org/details/nomenclatureofar14sudw/ |access-date=30 May 2024}} Variants on this name include "common honey locust", "honeylocust",{{cite book |last1=Pearson |first1=Dan |title=Natural Selection : a year in the garden |date=2017 |publisher=Guardian Books/Faber & Faber |location=London |isbn=978-1-78335-117-6 |page=211 |url=https://archive.org/details/naturalselection0000pear/page/211 |access-date=30 May 2024}} and "thornless honey locust".

Though honey locust is the most commonly used name for the species in English, it has a variety of other names. Some of these many names include "honey shucks locust", "sweet bean tree", "sweet locust", "thorny locust", and "green locust tree".{{cite book |last1=Dietz |first1=S. Theresa |title=The Complete Language of Flowers : A Definitive and Illustrated History |date=2020 |publisher=Wellfleet Press |location=New York |isbn=978-1-57715-190-6 |page=99 |url=https://archive.org/details/the-complete-language-of-flowers-a-definitive-and-illustrated-history-complete-i/page/n100 |access-date=30 May 2024}} In South Africa it is called "driedoringboom", driedoring-gleditsia", soetpeulboom", "springkaanboom", or "leoka".

In the late 1800s it was known by additional local names including "black locust" (MS, TX, AR, KS, NB), "three-thorned acacia" (MA, RI, LA, TX, MI, NB, Onterio), "thorntree" (NY, IN, LA), "thorny acacia" (TN), and "piquant amourette" (LA).

The native range of the honey locust is widely agreed to be from northern Mexico through the Gulf Coast of the United States, northwards into the Midwest, parts of the US East Coast, and the southernmost parts of Canada.{{cite web |last1=Hassler |first1=Michael |title=Synonymic Checklist and Distribution of the World Flora. Version 19.3 |url=https://www.worldplants.de |website=World Plants |access-date=1 June 2024 |language=en |date=18 May 2024}} In Canada it is a rare forest species found in southern Ontario near Lake Huron, Ontario, or Erie.{{cite web |title=Honey-Locust - Gleditsia triacanthos |url=https://arboretum.uoguelph.ca/thingstosee/trees/honeylocust |website=The Arboretum |publisher=University of Guelph |access-date=1 June 2024}} However, Plants of the World Online (POWO) lists it as introduced to Ontario while NatureServe and World Plants list it as native. It is listed as native to Nova Scotia by World Plants, but as introduced by POWO and not recorded by NatureServe. It is also recorded by NatureServe as growing as an introduced plant on Prince Edward Island.

In the midwest it grows in very widely in Illinois, Indiana, Ohio, and Missouri and is much rarer and scattered in Wisconsin and Minnesota, North Dakota. In Kansas it grows naturally in the eastern half of the state, and at the eastern and northern edge of Nebraska along the Missouri River, a small area of South Dakota, and the southern portion of Michigan.{{cite web |last1=Little, Jr. |first1=Elbert L. |title=Digital Representations of Tree Species Range Maps from "Atlas of United States Trees" : Gleditsia trianthos |url=http://esp.cr.usgs.gov/data/little/gledtria.pdf |website=Geosciences and Environmental Change Science Center |publisher=United States Geological Survey |access-date=1 June 2024 |archive-url=https://web.archive.org/web/20130606124808/http://esp.cr.usgs.gov/data/little/gledtria.pdf |archive-date=6 June 2013 |url-status=dead}}

In the eastern United States honey locust trees are regarded as native to Connecticut, Massachusetts, New Hampshire, Rhode Island, and New York. Though the botanist Elbert Luther Little showed the range as extending naturally into Pennsylvania, NatureServe list it as introduced to that state. They likewise list it as introduced to Maine, Vermont, and New Jersey, while both POWO and World Plants list it as native to all of them.

In the American South, only NatureServe lists it as introduced to Delaware and the District of Columbia, while World Plants lists it as native to both. Plants of the World Online does not list it as growing wild in Washington, D.C. It is listed as growing natively through all the rest of the south, though Elbert Luther Little's range map does not show it growing east of the Appalachian Mountains. Also, in Florida it is only shown as growing in a few isolated areas of the Florida Panhandle.

To the west it grows throughout eastern Texas and Oklahoma, while becoming scattered and isolated to the west. It is listed as introduced to New Mexico by POWO, but native in Wyoming, Utah, and Nevada. Contradicting this, NatureServe list it as native to New Mexico, while introduced in Colorado, Wyoming, Utah, and Nevada. Only World Plants lists it as native to many western states including Arizona, California, Colorado, Idaho, Montana, New Mexico, Nevada, Utah, and Wyoming.

In Mexico it grows in four states; Coahuila, Nuevo León, Sonora, and Tamaulipas. Trees in Mexico are much smaller than those in the center of its range, reaching a maximum size of just {{cvt|12|m|feet|0}} and less than {{cvt|6|m|feet|0}} in some populations. They are also found in isolated locations growing on south facing slopes at elevations of {{convert|1170 to 1400|m|abbr=on}}.{{cite journal |last1=Estrada-Castillón |first1=Eduardo |last2=Jurado |first2=Enrique |last3=Jiménez-Pérez |first3=Javier |title=New Locality of Gleditsia triacanthos (Caesalpiniaceae) in Northeastern Mexico and Its Phytogeographic Interest |journal=The Southwestern Naturalist |date=2002 |volume=47 |issue=4 |pages=602–604 |doi=10.2307/3672664 |jstor=3672664 |url=https://www.jstor.org/stable/3672664 |access-date=4 June 2024 |issn=0038-4909}}

Worldwide it has become established outside of cultivation in Europe, southern Asia, Australia, southern Africa, and in Argentina and Uruguay.

In its native range the honey locust grows in humid or subhumid climates.{{cite web |last1=Davis |first1=Costanza |title=Gleditsia triacanthos |url=https://sites.lafayette.edu/campustrees/2016/05/16/gleditsia-triacanthos/ |website=Campus Tree Project |publisher=Lafayette College |access-date=1 June 2024 |archive-url=https://web.archive.org/web/20231218223032/https://sites.lafayette.edu/campustrees/2016/05/16/gleditsia-triacanthos/ |archive-date=18 December 2023 |location=Easton, Pennsylvania |language=en |date=16 May 2016 |url-status=live}} It grows best in soils that are organically rich and moist, but well-drained. However, it is tolerant of a wide range of soil conditions. It is intolerant of shade and is a minor component of forests.

The sweet pulp in honey locust seed pods is attractive as a food for many animals including cattle, deer, rabbits, squirrels, and hares. White-tailed deer are known to disperse the seeds of honey locust by consuming the pods and passing the seeds in their dung. It is likely that deer move the seeds over one kilometer from where they are eaten, though probably not more than three kilometers and aid the tree in reaching new habitats and maintaining its wild population even in fragmented habitats. The seeds themselves are consumed by crows in the winter.

The size and number of thorns on the honey locust are thought to have evolved to protect the trees from browsing Pleistocene megafauna, including mastodons, which may also have been involved in seed dispersal.{{Cite web|title=Honeylocusts and Mastodons|url=https://bygl.osu.edu/node/959|access-date=2021-07-12|website=bygl.osu.edu|date=2 January 2018 |language=en}}

The seeds of the honey locust are resistant to sprouting without damage to the seed coat. In controlled experiments only 5% of the seeds sprout without treatment. In comparison, seeds soaked in concentrated sulfuric acid for one and a half hours increased germination to 68% and two and a half hours increases it to 98%.{{cite journal |last1=Fordham |first1=Alfred J. |title=Germination of Woody Legume Seeds with Impermeable Seed Coats |journal=Arnoldia |date=1965 |volume=25 |issue=1 |pages=1–8 |doi=10.5962/p.249445 |jstor=42953763 |url=https://www.jstor.org/stable/42953763 |access-date=3 June 2024 |issn=0004-2633}}

The honey locust moth (Syssphinx bicolor) feeds on honey locust and Kentucky coffee trees while a caterpillar. The first brood of the moths emerge from hibernation in the ground in the late spring. The green larvae have several horns on the backs and reach full size in about three weeks. When they reach full size they pupate in the soil. There may be two or three broods in a year.{{cite book |last1=Bouseman |first1=John K. |last2=Sternburg |first2=James G. |title=Field Guide to Silkmoths of Illinois |date=2002 |publisher=Illinois Natural History Survey |location=Champaign, Illinois |isbn=978-1-882932-06-1 |pages=38–39 |url=https://archive.org/details/fieldguidetosilk00bous/page/38 |access-date=3 June 2024}}

Honey locust trees are a frequent host for the parasitic plant American mistletoe (Phoradendron leucarpum), but usually is not infected by large numbers of them and without suffering obvious damage.{{cite journal |last1=Musselman |first1=Lytton J. |title=Parasitic Weeds in the Southern United States |journal=Castanea |date=1996 |volume=61 |issue=3 |pages=271–292 |jstor=4033681 |url=https://www.jstor.org/stable/4033681 |access-date=4 June 2024 |issn=0008-7475}}

Honey locust is one of the most successful of the trees and shrubs in the pea family at invading new habitats worldwide.{{cite journal |last1=Ferreras |first1=Ana E. |last2=Funes |first2=Guillermo |last3=Galetto |first3=Leonardo |title=The role of seed germination in the invasion process of H oney locust ( Gleditsia triacanthos L ., F abaceae): comparison with a native confamilial |journal=Plant Species Biology |date=April 2015 |volume=30 |issue=2 |pages=126–136 |doi=10.1111/1442-1984.12041 |language=en}} The species is a major invasive environmental and economic weed in agricultural regions of Australia. The plant forms thickets and destroys the pasture required for livestock to survive. The thickets choke waterways and prevent both domestic and native animals from drinking and also harbour vermin. The spines cause damage to both people and domestic and native wildlife and puncture vehicle tires.{{cite web | url = http://www.environment.gov.au/cgi-bin/biodiversity/invasive/weeds/weeddetails.pl?taxon_id=21077 | title = Gleditsia triacanthos | author = | website = Weeds in Australia | publisher = Australian Government | access-date = January 23, 2017}}{{cite web | url = http://www.weeds.org.au/cgi-bin/weedident.cgi?tpl=plant.tpl&card=T13 | archive-url = https://web.archive.org/web/20160304113055/http://www.weeds.org.au/cgi-bin/weedident.cgi?tpl=plant.tpl&card=T13 | url-status = dead | archive-date = 2016-03-04 | title = Gleditsia triacanthos | author = | website = weeds.org }} In Argentina the trees were introduced in the early 1800s to be used as a landscape ornamental, as a forest tree, and in windbreaks. It escaped from cultivation and has invaded native grasslands, subtropical montane forest (yungas), and woodlands of the Gran Chaco. In much of the Midwest of the United States the honey locust is also considered a weed tree and a pest that establishes itself in farm fields.{{cite journal | author = Barlow C. | year = 2001 | title = Anachronistic fruits and the ghosts who haunt them | journal = Arnoldia | volume = 61 | issue = 2 | pages = 14–21 | doi = 10.5962/p.390407 | url = http://arnoldia.arboretum.harvard.edu/pdf/articles/2001-61-2-anachronistic-fruits-and-the-ghosts-who-haunt-them.pdf | access-date = 2017-01-23 | archive-date = 2021-02-20 | archive-url = https://web.archive.org/web/20210220160105/http://arnoldia.arboretum.harvard.edu/pdf/articles/2001-61-2-anachronistic-fruits-and-the-ghosts-who-haunt-them.pdf | url-status = dead }} In other regions of the world, ranchers and farmers who employ monocropping deem honey locust a nuisance weed; its fast growth allows it to out-compete grasses and other crops.

The oldest known tree is one growing in the Kozia Brana Cemetery in Bratislava, Slovakia. It was planted sometime between 1773 and 1793, making it approximately {{age|1783|04|1}} years old. When last measured in 2021 it had a diameter of {{convert|1.2|m|ft|sp=us}} and a height of {{convert|23.40|m|ft|sp=us}}.{{cite web |last1=Miklanek |first1=Martin |title=American Honey-locust 'Gledicia na cintorine Kozia Brana' at the cemetery Kozia Brana, Bratislava, Bratislava, Slovakia |url=https://www.monumentaltrees.com/en/svk/bratislava/bratislava/4331_cemeterykoziabrana/8767/ |website=Monumental Trees |access-date=25 July 2024 |language=en |date=2021}}

The largest recorded in the American National Register of Champion Trees is one growing in Botetourt County, Virginia. It was last reported as healthy in 2019. It has a diameter at breast height of about {{convert|6.5|ft|m|sp=us|order=flip}}, a height of {{cvt|103|ft|m|sp=us|order=flip}}, and a crown spread of {{cvt|112|ft|m|sp=us|order=flip}}.{{cite web |title=2021 National Register of Champion Trees |url=https://d3f9k0n15ckvhe.cloudfront.net/wp-content/uploads/2021/11/2021-National-Register-of-Champion-Trees.pdf |website=American Forests |access-date=25 July 2024 |language=en}}

Due to the honey locust's tolerance of urban problems such as salt spray, compacted soils, poor aeration, constrained planting areas, and pollution, it has been widely planted in cities.{{cite web |last1=Kling |first1=Gary J. |last2=Lindsey |first2=Christopher P. |last3=Zampardo |first3=Mark E. |title=Gleditsia triacanthos habit |url=https://woodyplants.nres.uiuc.edu/plant/gletr80 |website=UI Plants |publisher=University of Illinois at UIPLANTS |access-date=1 June 2024}}{{cite web |last1=Gilman |first1=Edward F. |last2=Watson |first2=Dennis G. |title=ENH438/ST279: Gleditsia triacanthos var. inermis: Thornless Honeylocust |url=https://edis.ifas.ufl.edu/publication/ST279 |website=Ask IFAS - Powered by EDIS |publisher=University of Florida |access-date=1 June 2024 |date=2006}} In addition it will adapt to relatively dry conditions and either alkaline or acidic soils. Once established it is also drought tolerant, though it grows best with good moisture. It was very widely planted as a replacement for American elm trees killed by Dutch elm disease,{{cite web |last1=Blair |first1=Robert M. |title=Gleditsia triacanthos L |url=https://www.srs.fs.usda.gov/pubs/misc/ag_654/volume_2/gleditsia/triacanthos.htm |website=Southern Research Station |publisher=United States Forest Service, U.S. Department of Agriculture |access-date=24 August 2024}} becoming somewhat overplanted in the 1970s.

However, due to its wide planting many problems have been discovered. Like maples and oaks, honey locust is particularly vulnerable to Ganoderma root rots, a fungal infection of the roots and lower trunk of the tree.{{cite web |title=Ganoderma Root Rots |url=https://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/insects-pests-and-problems/diseases/rot/ganoderma-root |website=Gardening Help |publisher=Missouri Botanical Garden |access-date=1 June 2024 |language=en}} Three insects are the main pests that attack the honey locusts in urban areas, honeylocust plant bug (Blepharidopterus chlorionis), mimosa webworm (Homadaula anisocentra), and honeylocust spider mite (Platytetranychus multidigituli).{{cite journal |last1=Sperry |first1=Chad |last2=Chaney |first2=William |last3=Shao |first3=Guofan |last4=Sadof |first4=Clifford |title=Effects of Tree Density, Tree Species Diversity, and Percentage of Hardscape on Three Insect Pests of Honeylocust |journal=Arboriculture & Urban Forestry |date=1 September 2001 |volume=27 |issue=5 |pages=263–271 |doi=10.48044/jauf.2001.028 |url=https://auf.isa-arbor.com/content/27/5/263 |access-date=24 August 2024 |language=en}} Thornless cultivars are especially subsceptable to damage by the Asian mimosa webworm. Though healthy trees are able to withstand one or two years of complete defoliation, stressed trees may be killed.{{cite web |last1=Knupp |first1=Barbara |last2=Hoover, Sr. |first2=Gregory A. |last3=Skvarla |first3=Michael |title=Mimosa Webworm |url=https://extension.psu.edu/mimosa-webworm |website=PennState Extension |access-date=1 June 2024 |language=en |date=16 March 2023}} The number of honey locust trees within {{convert|10|m|ft|sp=us}} increases attacks by the webworms as does the amount of impermeable hardscape surfaces out to {{cvt|20|m|ft}} from a tree.

Almost all varieties cultivated after 1950 do not have thorns.

A cultivar that has been nearly or wholly unavailable in the plant trade since the 1980s.{{cite book |last1=Jacobson |first1=Arthur Lee |title=North American Landscape Trees |date=1996 |publisher=Ten Speed Press |location=Berkeley, California |isbn=978-0-89815-813-7 |pages=228–232 |url=https://archive.org/details/northamericanlan0000jaco/page/228 |access-date=23 July 2024 |language=en}} It was sourced from a then 50-year-old tree in Beatrice, Nebraska by the Inter-State Nursery of Hamburg, Iowa in 1955.{{cite journal |last1=Santamour |first1=Frank |last2=McArdle |first2=Alice |title=Checklist of Cultivars of Honeylocust (Gleditsia Triacanthos L.) |journal=Arboriculture & Urban Forestry |date=1 September 1983 |volume=9 |issue=9 |pages=248–252 |doi=10.48044/jauf.1983.060 |url=https://joa.isa-arbor.com/request.asp?JournalID=1&ArticleID=1909&Type=2 |access-date=23 July 2024}} This cultivar is shaped similarly to an American elm with a wide, spreading top and is also thornless and nearly pod free.

The 'Continental' cultivar has especially large leaves of a darker blue-green shade during the summer.{{cite web |title=Gleditsia triacanthos f. inermis 'Continental' - Continental thornless honey locust |url=https://dawesarb.arboretumexplorer.org/taxon-22395.aspx |website=Arboretum Explorer |publisher=The Dawes Arboretum |access-date=23 July 2024 |language=en}} It is a large and vigorous selection with a narrow crown that is thornless and nearly seedless. It was introduced to plant commerce by Princeton Nursery of New Jersey in 1973 and patented in 1958.

Also known as 'Compacta', Gleditsia sinensis 'Inermis', Gleditsia aquatica 'Elegantissima', 'Globe Honey Locust' and 'Bushy Honey Locust', this cultivar had become very rare by 1996. It is a bushy tree with smaller leaflets with slow growth, only reaching about {{convert|4|m|ft|0|sp=us}} when 25 years old. It has a narrow vase shaped crown and is thornless. It is propagated on its own roots, from ground budding, and also top grafted. It was raised by the nurseryman Charles Breton of Orléans in France around 1880. It has, in some cases, reached large sizes of {{cvt|12|m|ft|0}} or {{cvt|9.75|m|ft|0}}.

This cultivar has a weeping form, with branches that cascade downward. Because it does not produce a leader it must be grafted onto a standard, an upright section of trunk, or be staked. It is reported to be both thornless and fruitless. The leaves are dark green in the summer and bright yellow in the autumn. It was introduced to the horticultural trade by the Duncan & Davies nursery in New Zealand in 1992. It is hardy to USDA zone 3.{{cite web |last1=Breen |first1=Patrick |title=Gleditsia triacanthos var. inermis 'Emerald Kascade' |url=https://landscapeplants.oregonstate.edu/plants/gleditsia-triacanthos-var-inermis-emerald-kascade |website=Landscape Plants |publisher=Oregon State University |access-date=23 July 2024}} It is alternatively spelled 'Emerald Cascade' by some sources.{{cite book |editor1-last=Bryant |editor1-first=Geoff |editor2-last=Rodd |editor2-first=Tony |title=Trees and Shrubs : A gardener's Encyclopedia |date=2010 |publisher=Firefly Books |location=Buffalo, New York |isbn=978-1-55407-836-3 |page=167 |url=https://archive.org/details/treesshrubsgarde0000unse/page/167}}

It is a popular cultivar that grows to only about {{convert|35|ft|m|sp=us|order=flip}} in height. It is of very regular growth habit with branches that emerge at right angles to the trunk and a symmetrical arrangement around it. It is noted for its rounded crown. Due to the lower emergence of main branches it requires significant amounts of pruning to be used as a street tree where clearance above vehicles is required.{{cite web |last1=Gilman |first1=Edward F. |last2=Watson |first2=Dennis G. |title=ENH439/ST280: Gleditsia triacanthos var. inermis 'Imperial': 'Imperial' Thornless Honeylocust |url=https://edis.ifas.ufl.edu/publication/ST280 |website=Ask IFAS - Powered by EDIS |publisher=University of Florida |access-date=23 August 2024 |date=2006}} It is used where a somewhat smaller shade tree is required.

This is a very popular cultivar of the honey locust. Trees have a straight trunk and branches that grow outward and then curve upward to create a symmetrical crown. Very often, without trimming, they will have three or four leaders. At 15 years of age the top of the tree is relatively flat, creating a vase like shape. Compared with 'Skyline' it has a finer branch structure and wider angles where branches attach to the trunk.{{cite journal |last1=Haserodt |first1=Heidi |last2=Sydnor |first2=T. Davis |title=Growth Habits of Five Cultivars of Gleditsia Triacanthos |journal=Arboriculture & Urban Forestry |date=1 July 1983 |volume=9 |issue=7 |pages=186–189 |doi=10.48044/jauf.1983.046 |url=https://auf.isa-arbor.com/content/9/7/186 |access-date=24 July 2024}} Sources disagree on the maximum height obtained by this cultivar, Purdue lists it as {{cvt|45|ft|m|0|order=flip}} while the University of Florida lists it as {{cvt|50 to 70|ft|m|0|order=flip}}.{{cite web |title=Gleditsia triacanthos f. inermis [sold as Shademaster®] |url=https://www.arboretum.purdue.edu/explorer/plants/263/ |website=Purdue Arboretum Explorer |publisher=Purdue University |access-date=24 July 2024}} Trees will produces a few pods when mature and are thornless with dark green foliage in summer.{{cite web |title=Thornless Common Honeylocust |url=https://cmg.extension.colostate.edu/volunteer-information/cmg-gardennotes-class-handouts/thornless-common-honeylocust/ |website=Colorado Master Gardener |publisher=Colorado State University Extension |access-date=24 July 2024 |language=en}}

This is a very common cultivar that has a more pyramidal or slightly squared shape to its canopy. Full grown trees may reach a height of {{convert|50|ft|m|sp=us|order=flip}} or more. Of five standard cultivars including 'Imperial, 'Moraine', 'Shademaster', and 'Sunburst' it showed the greatest height after 15 years of growth. Trees tend to have one or two larger leaders and evenly spaced branches with somewhat narrower crotch angles. Trees can be trimmed to develop one strong central leader with little pruning, because of this lower branches can be removed without distoring the even shape of the crown. This habits make it appropriate as a street tree where lower branches must be removed.{{cite web |last1=Gilman |first1=Edward F. |last2=Watson |first2=Dennis G. |title=ENH441/ST282: Gleditsia triacanthos var. inermis 'Skyline': 'Skyline' Thornless Honeylocust |url=https://edis.ifas.ufl.edu/publication/ST280 |website=Ask IFAS - Powered by EDIS |publisher=University of Florida |access-date=23 August 2024 |date=2006}} The leaflets have a redish to bronze tone when emerging and a dark green and leathery appearance for most of the season. It was introduced by the Cole Nursery in Painesville, Ohio in 1957.

File:Unripe honey locust pods.jpg

The pulp on the inside of the pods is edible (unlike the black locust, which is toxic){{cite web|title=Toxicity of Black Locust|url=http://www.woodweb.com/knowledge_base/Toxicity_of_Black_Locust.html|website=www.woodweb.com|access-date=5 July 2016}} and consumed by wildlife and livestock.{{cite book |last=Little |first=Elbert L. |title=The Audubon Society Field Guide to North American Trees: Western Region |year=1994 |orig-year=1980 |publisher=Knopf |isbn=0394507614 |edition=Chanticleer Press|page=495}}

Despite its name, the honey locust is not a significant honey plant. The name derives from the sweet taste of the legume pulp, which was used for food and traditional medicine by Native American people, and can also be used to make tea. The long pods, which eventually dry and ripen to brown or maroon, are surrounded in a tough, leathery skin that adheres strongly to the pulp within. The pulp—bright green in unripe pods—is strongly sweet, crisp and succulent in ripe pods. Dark brown tannin-rich beans are found in slots within the pulp. Likewise, its edible seed has nutritional potential, and the flour made from its cotyledons constitutes a food source with various potential uses for pastry and bakery, among other gastronomic uses.{{Cite journal |last=Calfunao Antivil |first=Rosario |date=31 December 2011 |title=Characterization of the technological properties of flour of acacia thorns three (Gleditsia triacanthos L.) |url=https://core.ac.uk/display/44607876 |access-date=12 January 2023 |website=CORE |language=Spanish, English}}

File:Gleditsia triacanthos MHNT.BOT.2006.0.1274.JPG

Honey locusts produce a high quality, durable wood that polishes well, but the tree does not grow in sufficient numbers to support a bulk industry. However, a niche market exists for honey locust furniture. It is also used for posts and rails because of the dense, rot-resistant nature of the wood. The heartwood of honey locust is reddish brown while the sapwood is pale yellow. It is strong, but has a coarse grain texture.{{cite journal |last1=Kaiser |first1=Jo-Ann |title=Honeylocust: the thorny tree of the midwest |journal=Wood & Wood Products |date=August 1994 |volume=99 |issue=9 |page=32}}

The ability of Gleditsia to fix nitrogen is disputed. Many scientific sources{{cite conference | author = Burton JC. | editor = Zimmerman JH. | title = Nodulation and symbiotic nitrogen fixation by prairie legumes | book-title = Proceedings, 2nd Midwest Prairie Conference | url = http://images.library.wisc.edu/EcoNatRes/EFacs/NAPC/NAPC02/reference/econatres.napc02.jburton.pdf | access-date = 2017-01-23 | archive-date = 2017-02-02 | archive-url = https://web.archive.org/web/20170202045339/http://images.library.wisc.edu/EcoNatRes/EFacs/NAPC/NAPC02/reference/econatres.napc02.jburton.pdf | url-status = dead }}{{cite book |last1=Allen |first1=ON |last2=Allen |first2=EK |author-link2=Ethel K. Allen | title = The Leguminosae: A Source Book of Characteristics, Uses, and Nodulation | year = 1981 | location = Madison, WI | publisher = The University of Wisconsin Press | pages = 812 | isbn = 978-0-299-08400-4}}{{cite journal |vauthors=Djumaeva D, Lamers JP, Martius C, Khamzina A, Ibragimov N, Vlek PL | title = Quantification of symbiotic nitrogen fixation by Elaeagnus angustifolia L. on salt-affected irrigated croplands using two ¹⁵N isotopic methods | journal = Nutrient Cycling in Agroecosystems | volume = 88 | issue = 3 | pages = 329–339 | doi = 10.1007/s10705-010-9357-5| year = 2010 | bibcode = 2010NCyAg..88..329D | s2cid = 8129669 }} state that Gleditsia does not fix nitrogen. Some support this statement with the fact that Gleditsia does not form root nodules with symbiotic bacteria, the assumption being that without nodulation, no nitrogen fixation can occur. In contrast, many popular sources, permaculture publications in particular, claim that Gleditsia does fix nitrogen but by some other mechanism.{{citation needed|date=December 2021}}

There are anatomical, ecological, and taxonomic indications of nitrogen fixation in non-nodulating legumes.{{cite journal |vauthors=Bryan JA, Berlyn GP, Gordo JC | year = 1996 | title = Toward a new concept of the evolution of symbiotic nitrogen fixation in the Leguminosae | journal = Plant and Soil | volume = 186 | issue = 1 | pages = 151–159 | doi = 10.1007/BF00035069| bibcode = 1996PlSoi.186..151B | s2cid = 42530237 }} Both nodulating and non-nodulating species have been observed to grow well in nitrogen-poor soil with non-nodulating legumes even dominating some sites. The litter and seeds of non-nodulating species contain levels of nitrogen higher than non-legumes and sometimes even higher than nodulating legumes growing on the same site.{{cite thesis | author = Bryan J. | date = 1995 | title = Leguminous trees with edible beans, with indications of a rhizobial symbiosis in non-nodulating legumes | url = http://search.library.yale.edu/catalog/9841083?counter=2 | type = Ph.D. | publisher = Yale University | docket = UMI95-41400}} How this happens is not yet well understood but there have been some observations of nitrogenase activity in non-nodulating leguminous plants, including honey locust. Electron microscopy indicates the presence of clusters around the inner cortex of roots, just outside the xylem, that resemble colonies of rhizobial bacterioids. These may well constitute the evolutionary precursors in legumes for nitrogen fixation through nodulation. It is not known whether the non-nodulating nitrogen fixation, if it exists, benefits neighboring plants as is said to be the case with nodulating legumes.

In research using databases, more than 60 phytochemicals were identified from honey locust, including polyphenols, triterpenes, sterols, and saponins, with in vitro studies assessing for possible biological activity.{{cite journal|pmid=26643065|year=2016|last1=Zhang|first1=J. P.|title=Gleditsia species: An ethnomedical, phytochemical and pharmacological review|journal=Journal of Ethnopharmacology|volume=178|pages=155–71|last2=Tian|first2=X. H.|last3=Yang|first3=Y. X.|last4=Liu|first4=Q. X.|last5=Wang|first5=Q|last6=Chen|first6=L. P.|last7=Li|first7=H. L.|last8=Zhang|first8=W. D.|doi=10.1016/j.jep.2015.11.044}}

{{Reflist|32em}}

• {{Silvics | volume = 2 | genus = Gleditsia | species = triacanthos | first = RM. | last = Blair}}
• {{cite book | author = Little EL. | title = The Audubon Society Field Guide to North American Trees—Western Region | location = New York | publisher = Alfred A. Knopf | pages = 640 | year = 1980 | isbn = 978-0-394-50761-3}}
• {{cite book | author = Philips R. | title = Trees of North America and Europe | location = New York | publisher = Random House | isbn = 978-0-394-50259-5 | year = 1979 | pages = [https://archive.org/details/treesofnorthamer00phil/page/224 224] | url = https://archive.org/details/treesofnorthamer00phil/page/224 }}
• {{cite book |vauthors=Sternberg G, Wilson J | title = Native Trees for North American Landscapes | pages = 552 | publisher = Timber Press | location = Portland, OR | year = 2004 | isbn = 978-0-881-92607-1}}
• {{FEIS | type = tree | genus = Gleditsia | species = triacanthos | last = Sullivan | first = J. | date = 1994}}

{{Commons category|Gleditsia triacanthos}}

• [https://web.archive.org/web/20151102235720/http://www.cas.vanderbilt.edu/bioimages/species/frame/gltr.htm Gleditsia triacanthos images] at bioimages.Vanderbilt.edu
• [http://www.forestryimages.org/search/action.cfm?q=Gleditsia%20triacanthos Gleditsia triacanthos images] at Forestry Images
• [https://plants.usda.gov/home/plantProfile?symbol=GLTR Gleditsia triacanthos] at the USDA Plants Database

{{Taxonbar|from=Q157650}}

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Category:Edible legumes

Category:Gleditsia

Category:Flora of the North-Central United States

Category:Flora of the Northeastern United States

Category:Flora of the South-Central United States

Category:Flora of the Southeastern United States

Category:Flora of Coahuila

Category:Flora of Nuevo León

Category:Flora of Ontario

Category:Flora of Sonora

Category:Flora of Tamaulipas

Category:Ornamental trees

Category:Plants described in 1753

Category:Plants used in Native American cuisine

Category:Plants used in traditional Native American medicine

Category:Trees of Northern America