View source for Malus

{{short description|Flowering genus, rose family Rosaceae}}
{{hatnote|"Crabapple" redirects here. For the cultivated fruit, see [[Apple]]. For the Australian tree, see [[Pouteria eerwah]]. For other uses, see [[Crabapple (disambiguation)]] and [[Malus (disambiguation)]]}}

{{Automatic taxobox
| oldest_fossil = Eocene
| image = Purple prince crabapple tree.JPG
| image_caption = ''Malus'' ‘Purple Prince'<ref>Cirrus Digital [http://www.cirrusimage.com/tree_Purple_Prince_Crabapple.htm Purple Prince Crabapple]</ref>
| display_parents = 3
| taxon = Malus
| authority = [[Philip Miller|Mill.]]
| subdivision = See text
| type_species = ''Malus sylvestris''
| type_species_authority = [[Philip Miller|Mill.]] (1768)
| synonyms =
* ''Chloromeles'' {{small|(Decne.) Decne. (1882)}}
* ''Docynia'' {{small|Decne. (1874)}}
* ''Eriolobus'' {{small|(Ser.) M.Roem.(1847)}}
* ''Prameles'' {{small|Rushforth (2018)}}
* ''Sinomalus'' {{small|Koidz. (1932)}}
* ''× Tormimalus'' {{small|Holub (1998)}}
| synonyms_ref = <ref name = powo>{{cite web |work=Plants of the World Online |title=''Malus'' Mill. |url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:30024474-2 |publisher=Royal Botanic Gardens, Kew |access-date=17 December 2023}}</ref>
}}

'''''Malus''''' ({{IPAc-en|ˈ|m|eɪ|l|ə|s}}<ref>''Sunset Western Garden Book,'' 1995:606–607</ref> or {{IPAc-en|ˈ|m|æ|l|ə|s}}) is a [[genus]] of about 32–57 [[species]]<ref>{{cite journal |title=A checklist of the subfamily Maloideae (Rosaceae)| journal=Can. J. Bot.| year=1990| volume=68 | pages=2209–2269 | doi=10.1139/b90-288 | issue=10 | last1=Phipps| first1=James B.| last2=Robertson| first2=Kenneth R.| last3=Smith| first3=Paul G.| last4=Rohrer |first4=Joseph R.| bibcode=1990CaJB...68.2209P}}</ref> of small [[deciduous]] [[tree]]s or [[shrub]]s in the family [[Rosaceae]], including the domesticated orchard [[apple]], '''crab apples''' (sometimes known in North America as '''crabapples''') and '''wild apples'''.

The genus is [[native plant|native]] to the [[temperate]] zone of the [[Northern Hemisphere]].

==Description==
Apple trees are typically {{convert|4|–|12|m|ft|abbr=off}} tall at maturity, with a dense, twiggy crown. The [[Leaf |leaves]] are {{convert|3|–|10|cm|in|abbr=off|frac=4}} long, alternate, simple, with a serrated margin. The [[flower]]s are borne in [[corymb]]s, and have five [[petal]]s, which may be white, pink, or red, and are [[Plant reproductive morphology|perfect]], with usually red stamens that produce copious [[pollen]], and a [[Ovary (botany)#Half-inferior_ovary|half-inferior ovary]]; flowering occurs in the spring after 50–80 [[growing degree-day]]s, varying greatly according to subspecies and [[cultivar]].{{Citation needed|date=March 2023}}

Many apples require [[Pollination#Mechanism|cross-pollination]] between individuals by [[insect]]s (typically [[bee]]s, which freely visit the flowers for both [[nectar]] and [[pollen]]); these are called self-sterile, so self-pollination is impossible, making pollinating insects essential.<ref>{{Cite web |last=coreyrametta |date=2019-06-11 |title=Are Apple Trees Self Pollinating? |url=https://coldhardyfruits.com/apple-trees/are-apple-trees-self-pollinating/ |access-date=2024-05-02 |website=Cold Hardy Fruits |language=en-US}}</ref>

A number of cultivars are self-pollinating, such as "Granny Smith" and "Golden Delicious", but there are fewer self-pollinating varieties than cross-pollinating ones.{{Citation needed|date=March 2023}} Several ''Malus'' species, including domestic apples, [[Hybrid (biology)|hybridize]] freely.<ref>{{cite web|url=http://www.omafra.gov.on.ca/english/crops/facts/00-011.htm|title=Crabapple Pollenizers for Apples|publisher=Ontario Ministry of Agriculture and Food|author=Ken Wilson and D.C. Elfving|access-date=12 Sep 2013}}</ref>

The [[fruit]] is a globose [[pome]], varying in size from {{convert|1|–|4|cm|in|abbr=on|frac=4}} in diameter in most of the wild species, to {{convert|6|cm|in|abbr=on|frac=4}} in ''M.&nbsp;sylvestris sieversii'', {{convert|8|cm|in|abbr=on|frac=2}} in ''M.&nbsp;domestica'', and even larger in certain cultivated orchard apples. The centre of the fruit contains five [[Gynoecium#Carpels|carpels]] arranged star-like, each containing one or two [[seed]]s.{{Citation needed|date=March 2023}}

{{gallery|mode=packed
|20071103Tradkrafta1.JPG|Trunk
|Flowering crabapple in Washington DC.jpg|Crabapple blossoms
|Apple blossom. Eastern Siberia.jpg|Eastern [[Siberia]]
}}

== Subdivision ==
36 species and 4 hybrids are accepted.<ref name=powo/> The genus ''Malus'' is subdivided into eight sections (six, with two added in 2006 and 2008).{{citation needed|date=April 2023}} The oldest fossils of the genus date to the [[Eocene]] ([[Lutetian]]), which are leaves belonging to the species ''Malus collardii'' and ''Malus kingiensis'' from western North America (Idaho) and the [[Russian Far East]] ([[Kamchatka]]), respectively.<ref name=":0">{{Cite journal |last1=Liu |first1=Bin-Bin |last2=Ren |first2=Chen |last3=Kwak |first3=Myounghai |last4=Hodel |first4=Richard G.J. |last5=Xu |first5=Chao |last6=He |first6=Jian |last7=Zhou |first7=Wen-Bin |last8=Huang |first8=Chien-Hsun |last9=Ma |first9=Hong |last10=Qian |first10=Guan-Ze |last11=Hong |first11=De-Yuan |last12=Wen |first12=Jun |date=May 2022 |title=Phylogenomic conflict analyses in the apple genus Malus s.l. reveal widespread hybridization and allopolyploidy driving diversification, with insights into the complex biogeographic history in the Northern Hemisphere |url=https://onlinelibrary.wiley.com/doi/10.1111/jipb.13246 |journal=Journal of Integrative Plant Biology |language=en |volume=64 |issue=5 |pages=1020–1043 |doi=10.1111/jipb.13246 |pmid=35274452 |bibcode=2022JIPB...64.1020L |s2cid=247384781 |issn=1672-9072|url-access=subscription }}</ref>

=== Species ===
36 species and four natural hybrids are accepted:<ref name = powo/>
{{div col|colwidth=25em}}
* ''[[Malus angustifolia]]'' {{small|(Aiton) Michx.}} – southern crabapple
* ''[[Malus asiatica]]'' {{small|Nakai}} – Chinese pearleaf crabapple
* ''[[Malus baccata]]'' {{small|(L.) Borkh.}} – Siberian crabapple
* ''[[Malus brevipes]]'' – shrub apple
* ''[[Malus coronaria]]'' {{small|(L.) Mill.}} – sweet crabapple
* ''[[Malus crescimannoi]]'' {{small|Raimondo}}
* ''[[Malus daochengensis]]'' {{small|C.L.Li}}
* ''[[Malus domestica]]'' {{small|(Suckow) Borkh.}} – domestic or orchard apple
* ''[[Malus doumeri]]'' {{small|(Bois) A.Chev.}} – Taiwan crabapple
* ''[[Malus florentina]]'' {{small|(Zuccagni) C.K.Schneid.}} – Florentine crabapple, hawthorn-leaf crabapple
* ''[[Malus fusca]]'' {{small|(Raf.) C.K.Schneid.}} – Oregon or Pacific crabapple
* ''[[Malus halliana]]'' {{small|Koehne}} – Hall crabapple
* ''[[Malus honanensis]]'' {{small|Rehder}}
* ''[[Malus hupehensis]]'' {{small|(Pamp.) Rehder}} – tea crabapple
* ''[[Malus ioensis]]'' {{small|(Alph.Wood) Britton}} – prairie crabapple
* ''[[Malus jinxianensis]]'' {{small|J.Q.Deng & J.Y.Hong}}
* ''[[Malus kansuensis]]'' {{small|(Batalin) C.K.Schneid.}} – Calva crabapple
* ''[[Malus komarovii]]'' ({{small|Sarg.) Rehder}}
* ''[[Malus leiocalyca]]'' {{small|S.Z.Huang}}
* ''[[Malus mandshurica]]'' {{small|(Maxim.) Kom. ex Skvortsov}}
* ''[[Malus muliensis]]'' {{small|T.C.Ku}}
* ''[[Malus niedzwetzkyana]]'' – Niedzwetzky's Apple
* ''[[Malus ombrophila]]'' {{small|Hand.-Mazz.}}
* ''[[Malus orientalis]]'' {{small|Uglitzk.}}
* ''[[Malus prattii]]'' {{small|(Hemsl.) C.K.Schneid.}} – Pratt's crabapple
* ''[[Malus prunifolia]]'' {{small|(Willd.) Borkh.}} – plum-leaf crabapple, Chinese crabapple
* ''[[Malus rockii]]'' {{small|Rehder}} – native to China and Bhutan
* ''[[Malus sikkimensis]]'' {{small|(Wenz.) Koehne}} – Sikkim crabapple
* ''[[Malus spectabilis]]'' {{small|(Aiton) Borkh.}} – Asiatic apple, Chinese crabapple
* ''[[Malus spontanea]]'' {{small|(Makino) Makino}} - nokaidō
* ''[[Malus sylvestris]]'' {{small|(L.) Mill.}} – European crabapple
* ''[[Malus toringo]]'' {{small|(Siebold) de Vriese}} (syns. ''[[Malus sargentii]]'', ''[[Malus sieboldii]]'') – Sargent crabapple, Toringo crabapple, or Siebold's crabapple
* ''[[Malus toringoides]]'' {{small|(Rehder) Hughes}} – cut-leaf crabapple
* ''[[Malus transitoria]]'' {{small|(Batalin) C.K.Schneid.}} – cut-leaf crabapple
* ''[[Malus trilobata]]'' {{small|(Labill. ex Poir.) C.K.Schneid.}} – Lebanese wild apple, erect crabapple, or three-lobed apple tree
* ''[[Malus turkmenorum]]'' {{small|Juz. & Popov}} (syn. ''[[Malus sieversii]]'') – wild ancestor of cultivated species ''[[Malus domestica]]''
* ''[[Malus yunnanensis]]'' {{small|(Franch.) C.K.Schneid.}} – Yunnan crabapple
* ''[[Malus zhaojiaoensis]]'' {{small|N.G.Jiang}}
;Hybrids
* ''[[Malus × floribunda]]'' {{small|Siebold ex Van Houtte}} – Japanese flowering crabapple
* ''[[Malus × kaido]]'' {{small|(Wenz.) Pardé}} (syn. ''[[Malus × micromalus]]'') – midget crabapple
* ''[[Malus × soulardii]]'' {{small|(L.H.Bailey) Britton}}
* ''[[Malus × zumi]]'' {{small|(Matsum.) Rehder}}
{{div col end}}

===Formerly placed here===
* ''[[Macromeles tschonoskii]]'' {{small|(Maxim.) Koidz.}} (as ''Malus tschonoskii'' {{small|(Maxim.) C.K.Schneid.}}) – Chonosuki crabapple and pillar apple{{cn|date=December 2023}}

===Selected artificial hybrids===
* ''[[Malus × sublobata]]'' – yellow autumn crabapple (''M. asiatica'' × ''M. toringo'')

=== Fossil species ===
After<ref name=":0" />
* ''Malus collardii'' Axelrod, North America (Idaho), [[Eocene]]
* ''Malus kingiensis'' Budants, Kamchatka Peninsula, Russia, Eocene
* ''Malus florissantensis'' (Cockerell) MacGinitie [[Green River Formation]], North America (Colorado) Eocene
* ''Malus pseudocredneria'' (Cockerell) MacGinitie Green River Formation, North America (Colorado) Eocene
* ''Malus idahoensis'' R.W.Br. North America (Idaho), [[Miocene]]
* ''Malus parahupehensis'' J.Hsu and R.W.Chaney [[Shanwang National Geological Park|Shanwang]], Shandong, China, Miocene
* ''Malus antiqua'' Doweld Romania, [[Pliocene]]
* ''Malus pseudoangustifolia'' E.W.Berry North America (South Carolina), [[Pleistocene]]

== Cultivation ==
{{See also|Fruit tree pollination}}
[[File:Malus evereste.JPG|thumb|upright=1.2|'Evereste' fruits]]
[[File:Crabapple bonsai - late summer photo.JPG|thumb|upright|Crabapple bonsai tree in August]]

Crabapples are popular as compact ornamental trees, providing blossom in spring and colourful fruit in autumn. The fruits often persist throughout winter. Numerous hybrid cultivars have been selected.{{cn|date=March 2023}}

Some crabapples are used as [[rootstock]]s for domestic apples to add beneficial characteristics.<ref>[https://www.gardening.cornell.edu/factsheets/ecogardening/appleroot.html Apple Tree Rootstocks Ecogardening Factsheet #21, Summer 1999]</ref> For example, the rootstocks of ''[[Malus baccata]]'' varieties are used to give additional cold hardiness to the combined plants for orchards in cold northern areas.<ref>[http://www.dnr.state.ak.us/ag/21Applerootstocks.pdf Apple Rootstocks], Alaska Department of Natural Resources {{webarchive|url=https://web.archive.org/web/20080719050542/http://www.dnr.state.ak.us/ag/21Applerootstocks.pdf |date=2008-07-19 }}</ref>

They are also used as [[pollinizer]]s in apple [[orchard]]s. Varieties of crabapple are selected to bloom contemporaneously with the apple variety in an orchard planting, and the crabs are planted every sixth or seventh tree, or limbs of a crab tree are grafted onto some of the apple trees. In emergencies, a bucket or drum bouquet of crabapple flowering branches is placed near the beehives as orchard pollenizers.{{cn|date=March 2023}}

Because of the plentiful blossoms and small fruit, crabapples are popular for use in [[bonsai]] culture.<ref>{{cite web|last1=Biel|first1=John|title=Collecting and Training Crab Apples {{!}} American Bonsai Society|url=http://www.absbonsai.org/collecting-and-training-crab-apples|website=www.absbonsai.org|publisher=American Bonsai Society|access-date=2 August 2016|url-status=dead|archive-url=https://web.archive.org/web/20160703060433/http://www.absbonsai.org/collecting-and-training-crab-apples|archive-date=3 July 2016}}</ref><ref>{{cite web|title=Crabapple (Malus) - Bonsai Empire|url=http://www.bonsaiempire.com/tree-species/crabapple|website=www.bonsaiempire.com|access-date=2 August 2016}}</ref><ref>{{cite web|last1=Walston|first1=Brent|title=Crabapples for Bonsai|url=https://www.evergreengardenworks.com/crabappl.htm|website=evergreengardenworks.com|access-date=2 August 2016}}</ref>

===Cultivars===
These cultivars have won the [[Royal Horticultural Society]]'s [[Award of Garden Merit]]:<ref>{{cite web  | url= https://www.rhs.org.uk/plants/pdfs/agm-lists/agm-ornamentals.pdf | title = AGM Plants - Ornamental | date = July 2017 | page = 63 | publisher = Royal Horticultural Society | access-date = 2 April 2018}}</ref>

{{div col|colwidth=22em}}
* 'Adirondack'<ref>{{cite web | url = https://www.rhs.org.uk/Plants/138380/i-Malus-i-Adirondack/Details
| title = RHS Plantfinder - ''Malus'' 'Adirondack' | access-date = 25 March 2018}}</ref>
* 'Butterball'<ref>{{cite web | url = https://www.rhs.org.uk/Plants/85932/i-Malus-i-Butterball/Details
| title = RHS Plantfinder - ''Malus'' 'Butterball' | access-date = 25 March 2018}}</ref>
* 'Comtesse de Paris'<ref>{{cite web | url = https://www.rhs.org.uk/Plants/328341/Malus-Comtesse-de-Paris/Details | title = ''Malus'' 'Comtesse de Paris' | publisher = RHS | access-date = 6 January 2021}}</ref>
* 'Evereste'<ref>{{cite web | url = https://www.rhs.org.uk/Plants/116626/i-Malus-i-Evereste/Details
| title = RHS Plantfinder -''Malus'' 'Evereste' | access-date = 25 March 2018}}</ref>
* 'Jelly King'='Mattfru'<ref>{{cite web | url = https://www.rhs.org.uk/Plants/299501/i-Malus-i-Font-Face-times-New-Roman-Jelly-King-FONT-Mattfru/Details | title = RHS Plantfinder - ''Malus'' Jelly King = 'Mattfru' | access-date = 25 March 2018}}</ref>
* 'Laura'<ref>{{cite web | url = https://www.rhs.org.uk/Plants/124642/i-Malus-i-Laura/Details
| title = RHS Plantfinder - ''Malus'' 'Laura' | access-date = 25 March 2018}}</ref>
* ''[[Malus × robusta]]'' 'Red Sentinel'<ref>{{cite web | url = https://www.rhs.org.uk/Plants/45895/i-Malus-i-×-i-robusta-i-Red-Sentinel/Details
| title = RHS Plantfinder - ''Malus'' × ''robusta'' 'Red Sentinel' | access-date = 25 March 2018}}</ref>
* 'Sun Rival'<ref>{{cite web | url = https://www.rhs.org.uk/Plants/104053/i-Malus-i-Sun-Rival/Details
| title = RHS Plantfinder - ''Malus'' 'Sun Rival' | access-date = 25 March 2018}}</ref>
{{div col end}}

Other varieties are dealt with under their species names.

== Toxicity ==
The seeds contain [[cyanide]] compounds.<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=113 |language=en-US |oclc=277203364}}</ref>

== Uses ==
[[File:Crabapples.jpg|thumb|upright=1.2|Ripe apples (''[[Malus domestica|M.&nbsp;domestica]]'')]]
[[File:Lee-Russell-Farm-Security-Administration-1939-Crab-Apples.jpg|thumb|upright=1.2|Baskets of crab apples for sale in Connecticut in 1939]]

Crabapple fruit is not an important [[crop]] in most areas. The fruit is rarely eaten raw due to the [[sour]] taste resulting from high levels of [[malic acid]]. Some species have a woody texture. In some [[Southeast Asia]]n cultures, they are valued as a sour [[condiment]], sometimes eaten with salt and [[chili pepper|chilli]] or [[shrimp paste]].{{Citation needed|date = January 2016}}

Some varieties of crabapple, such as the 'Chestnut' cultivar<ref>{{cite web|url=http://www.starkbros.com/growing-guide/plant-manuals/fruit-trees/apple-trees/chestnut-crabapple|title=The Growing Guide|publisher=Stark Bro's Nurseries & Orchards Co.|archive-url=https://web.archive.org/web/20140726022654/http://www.starkbros.com/growing-guide/plant-manuals/fruit-trees/apple-trees/chestnut-crabapple|archive-date=2014-07-26}}</ref>, are sweet.

Crabapples are an excellent source of [[pectin]]. Using sugar and spices such as ginger, nutmeg, cinnamon, and allspice, their [[fruit juice|juice]] can be made into ruby-coloured crab apple [[jelly (fruit preserves)|jelly]] with a full, spicy flavour.<ref>{{cite book|last=Rombauer|first=I.|author-link=Irma S. Rombauer|author2=Becker, M. R. |author3=Becker, E. |title=All About Canning & Preserving (The Joy of Cooking series)|publisher=Scribner|location=New York|orig-year=2002|pages=72|isbn=0-7432-1502-8|year=2002}}</ref> A small percentage of crabapples in [[cider]] makes a more interesting flavour.<ref>{{cite web|url=http://www.cider.org.uk/part1.htm|title=The Science of Cidermaking|publisher=Andrew Lea|access-date=November 14, 2013}}</ref> As [[Old English]] {{Lang|ang|Wergulu}}, the crab apple is one of the nine plants invoked in the [[Anglo-Saxon paganism|pagan Anglo-Saxon]] ''[[Nine Herbs Charm]]'', recorded in the 10th century.

Applewood gives off a pleasant scent when burned, and smoke from an applewood fire gives an excellent flavour to [[smoking (cooking)|smoked]] foods.<ref name=Fraser>{{cite web |last=Fraser |first=Anna |title=Properties of different trees as firewood |date=22 August 2005|access-date=17 July 2008 |url=http://www.the-tree.org.uk/ }}</ref> It is easier to cut when green; dry applewood is exceedingly difficult to carve by hand.<ref name=Fraser/> It is a good wood for cooking fires because it burns hot and slow, without producing much flame.<ref name=Fraser/> Applewood is used to make handles of [[hand saw]]s; in the early 1900s, 2,000,000 board feet of applewood were used annually for this purpose.<ref>Burks, Jeff (2015). "Woods Used in Saw Handles". Lost Art Press, Traditional Hand-tool Skills. blog.lostartpress.com.</ref>

==References==
{{Reflist|30em}}

==External links==
{{Commons}}
* [https://web.archive.org/web/20070208143219/http://www.ext.vt.edu/departments/envirohort/articles/fruits_and_nuts/drescra.html Germplasm Resources Information Network: ''Malus'']
* [http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=119570 Flora of China: ''Malus'']
* [http://www.ext.vt.edu/departments/envirohort/articles/fruits_and_nuts/drescra.html Virginia Cooperative Extension - Disease resistant crabapples] {{webarchive |url=https://web.archive.org/web/20070208143219/http://www.ext.vt.edu/departments/envirohort/articles/fruits_and_nuts/drescra.html |date=8 February 2007 }}
* [https://www.hort.purdue.edu/newcrop/pri/default.html The PRI disease resistant apple breeding program]: a cooperative among [[Purdue University]], [[Rutgers University]], and the [[University of Illinois]].

{{Crabapple}}
{{US state flowers}}
{{Taxonbar|from=Q104819}}
{{Authority control}}

[[Category:Malus| ]]
[[Category:Rosaceae genera]]
[[Category:Plants used in bonsai]]
[[Category:Fruit trees]]
[[Category:Taxa named by Philip Miller]]