Malus is a genus of about 30–55 species of small deciduous apple trees or shrubs in the family Rosaceae this includes the domesticated orchard apple (M. pumila). The other species are generally known as crab apples, crabs, or wild apples. Malus are native to the Northern Hemisphere.
Malus are usually around 4 to 12 M in height at full maturity. The usually have a dense twiggy crown. They flower in the Spring, and the produce flowering blossoms of whites, Pinks and reds.
To produce the fruits Malus, need cross pollination, they are mostly self-sterile apart from a few specially developed cultivars. Pollinating insects are essential and Bees will visit the flowers for both pollen and nectar.
The fruit or ‘apple’ is globose in shape and can vary in size from 1-4cm in diameter for wild apples and up to 8cm plus for M.domestica and other cultivated orchard apples. The centre of the fruit is star shaped and each section contacins 2 seeds.
Crab apple fruit is not an important fruit in most areas, being extremely sour due to malic acid and in some species woody, and for this reason is rarely eaten raw. In some south east Asian cultures, they are valued as a sour condiment, sometimes eaten with salt and chilli pepper, or a shrimp paste.
Some crab apple varieties are an exception to the reputation of being sour, and can be very sweet, such as the ‘Chestnut’ cultivar.
Crab apples 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 crab apples 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 herb 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.