Malus (// or //) is a genus of about 30–55 species of small deciduous trees or shrubs in the family Rosaceae, including the domesticated orchard apple (M. pumila syn. M. domestica ) – also known as the eating apple, cooking apple, or culinary apple. It is dealt with under Apple. The other species are generally known as crabapples, crab apples, or wild apples.
|Malus ‘Purple Prince’|
Apple trees are typically 4–12 m (13–39 ft) tall at maturity, with a dense, twiggy crown. The leaves are 3–10 cm (1.2–3.9 in) long, alternate, simple, with a serrated margin. The flowers are borne in corymbs, and have five petals, which may be white, pink or red, and are perfect, with usually red stamens that produce copious pollen, and a half-inferior ovary; flowering occurs in the spring after 50–80 growing degree days (varying greatly according to subspecies and cultivar).
Apples require cross-pollination between individuals by insects (typically bees, which freely visit the flowers for both nectar and pollen); all are self-sterile, and (with the exception of a few specially developed cultivars) self-pollination is impossible, making pollinating insects essential. Several Malus species, including domestic apples, hybridize freely. They are used as food plants by the larvae of a large number of Lepidoptera species; see list of Lepidoptera that feed on Malus.
The fruit is a globose pome, varying in size from 1–4 cm (0.39–1.57 in) diameter in most of the wild species, to 6 cm (2.4 in) in M. sylvestris sieversii, 8 cm (3.1 in) in M. domestica, and even larger in certain cultivated orchard apples. The centre of the fruit contains five carpels arranged star-like, each containing one or two seeds.
For the Malus pumila cultivars, the culinary, and eating apples, see Apple.
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. The following have won the Royal Horticultural Society’s Award of Garden Merit:-
Other varieties are dealt with under their species names.
Some crabapples are used as rootstocks for domestic apples to add beneficial characteristics. For example, varieties of baccata, also called Siberian crab, rootstock is used to give additional cold hardiness to the combined plant for orchards in cold northern areas.
They are also used as pollinizers in apple orchards. 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 are placed near the beehives as orchard pollenizers. See also Fruit tree pollination.
Crabapple fruit is not an important crop in most areas, being extremely sour due to malic acid (which like the genus derives from the Latin name mālum), and in some species woody, and for this reason is rarely eaten raw. In some southeast Asian cultures they are valued as a sour condiment, sometimes eaten with salt and chili pepper, or shrimp paste.
Some crabapple varieties are an exception to the reputation of being sour, and can be very sweet, such as the 'Chestnut' cultivar.
Crabapples are an excellent source of pectin, and their juice can be made into a ruby-coloured preserve with a full, spicy flavour. A small percentage of crabapples in cider makes a more interesting flavour. As Old English Wergulu, the crab apple is one of the nine plants invoked in the pagan Anglo-Saxon Nine Herbs Charm, recorded in the 10th century.
Apple wood gives off a pleasant scent when burned, and smoke from an apple wood fire gives an excellent flavour to smoked foods. It is easier to cut when green; dry apple wood is exceedingly difficult to carve by hand. It is a good wood for cooking fires because it burns hot and slow, without producing much flame.
- Malus angustifolia – southern crabapple
- Malus asiatica – Chinese pearleaf crabapple
- Malus baccata – Siberian crabapple
- Malus brevipes – shrub apple
- Malus coronaria – sweet crabapple
- Malus doumeri – Taiwan crabapple
- Malus florentina – Florentine crabapple, hawthorn-leaf crabapple
- Malus floribunda – Japanese flowering crabapple
- Malus fusca – Oregon or Pacific crabapple
- Malus glabrata – Biltmore's crabapple
- Malus glaucescens – Dunbar crabapple
- Malus halliana – Hall crabapple
- Malus honanensis
- Malus hopa – lowering crabapple
- Malus hupehensis – tea crabapple
- Malus ioensis – prairie crabapple
- Malus kansuensis – Calva crabapple
- Malus komarovii
- Malus × micromalus – midget crabapple
- Malus niedzwetzkyana – Niedzwetzky's Apple
- Malus prattii – Pratt's crabapple
- Malus prunifolia – plum-leaf crabapple, Chinese crabapple
- Malus pumila – orchard apple
- Malus rockii – native to China and Bhutan
- Malus sargentii – Sargent crabapple
- Malus sieboldii – Toringo crabapple or Siebold's crabapple
- Malus sieversii – ancestor of cultivated species Malus pumila
- Malus sikkimensis – Sikkim crabapple
- Malus spectabilis – Asiatic apple, Chinese crabapple
- Malus sublobata – yellow autumn crabapple
- Malus sylvestris – European crabapple
- Malus toringoides – cut-leaf crabapple
- Malus transitoria – cut-leaf crabapple
- Malus trilobata – Lebanese wild apple, erect crabapple, or three-lobed apple tree
- Malus tschonoskii – Chonosuki crabapple and pillar apple
- Malus yunnanensis – Yunnan crabapple
- Cirrus Digital Purple Prince Crabapple
- Sunset Western Garden Book, 1995:606–607
- Phipps, J.B.; et al. (1990). "A checklist of the subfamily Maloideae (Rosaceae)". Can. J. Bot. 68 (10): 2209. doi:10.1139/b90-288.
- Ken Wilson and D.C. Elfving. "Crabapple Pollenizers for Apples". Ontario Ministry of Agriculture and Food. Retrieved 12 Sep 2013.
- "AGM Plants - Ornamental" (PDF). Royal Horticultural Society. July 2017. p. 63. Retrieved 2 April 2018.
- "RHS Plantfinder - Malus 'Adirondack'". Retrieved 25 March 2018.
- "RHS Plantfinder - Malus 'Butterball'". Retrieved 25 March 2018.
- "RHS Plantfinder -Malus 'Evereste'". Retrieved 25 March 2018.
- "RHS Plantfinder - Malus Jelly King = 'Mattfru'". Retrieved 25 March 2018.
- "RHS Plantfinder - Malus 'Laura'". Retrieved 25 March 2018.
- "RHS Plantfinder - Malus × robusta 'Red Sentinel'". Retrieved 25 March 2018.
- "RHS Plantfinder - Malus 'Sun Rival'". Retrieved 25 March 2018.
- Apple Tree Rootstocks Ecogardening Factsheet #21, Summer 1999
- Alaska Department of Natural Resources Archived 2008-07-19 at the Wayback Machine.
- Biel, John. "Collecting and Training Crab Apples | American Bonsai Society". www.absbonsai.org. American Bonsai Society. Archived from the original on 3 July 2016. Retrieved 2 August 2016.
- "Crabapple (Malus) - Bonsai Empire". www.bonsaiempire.com. Retrieved 2 August 2016.
- Walston, Brent. "Crabapples for Bonsai". evergreengardenworks.com. Retrieved 2 August 2016.
- "The Growing Guide". Stark Bro's Nurseries & Orchards Co.
- Rombauer, I.; Becker, M. R.; Becker, E. (2002) . All About Canning & Preserving (The Joy of Cooking series). New York: Scribner. p. 72. ISBN 0-7432-1502-8.
- "The Science of Cidermaking". Andrew Lea. Retrieved November 14, 2013.
- Fraser, Anna (22 August 2005). "Properties of different trees as firewood". Retrieved 17 July 2008.
- D. S. Vohra (1 June 2004). Bach Flower Remedies: A Comprehensive Study. B. Jain Publishers. p. 3. ISBN 978-81-7021-271-3. Retrieved 2 September 2013.
- "Malus x adstringens 'Durleo' 'Gladiator Crabapple'". Countryside Garden Centre. Countryside Garden Centre. Retrieved 6 June 2016.[permanent dead link]
|Wikimedia Commons has media related to Malus.|
- Germplasm Resources Information Network: Malus
- Flora of China: Malus
- Virginia Cooperative Extension - Disease resistant crabapples Archived 8 February 2007 at the Wayback Machine.
- The PRI disease resistant apple breeding program: a cooperative among Purdue University, Rutgers University, and the University of Illinois.