Identifying characteristics:
The genus Malus (sometimes listed under Pyrus, which includes
the pears) contains about 25 species and hundreds of cultivars, including
the apples (fruit larger than 2 inches in diameter) and the crabapples (fruit
smaller than 2 inches in diameter). The prairie or Iowa crab (M. ioensis)
is the only member of the genus definitely native to Iowa, and one of the
few species named for the state. Crabapples are small, adaptable, highly
ornamental, deciduous flowering trees or shrubs, up to 25 feet tall. The
leaves, which fall early in the
autumn, are simple, alternate, toothed, and in some species lobed. The thorns,
if present, have leaf scars, are not as shiny, and not as sharp as those
of hawthorns. Flowers appear before,
with, or slightly after the leaves in April and May. They are white, pink
or red, and are produced in small, showy clusters on leafy dwarf shoots.
Each flower has 5 (or more) rounded petals, numerous stamens, and 2 to 5
styles, each with a 5-chambered ovary and 1 or 2 seeds per chamber. The
fruit is a yellow, red or green pome
that often persists on the tree into winter. The leaf scars are small,
linear or crescent shaped, with 3 bundle scars. The buds are ovoid,
with 3 to 4 visible, reddish-brown scales with protruding hairs. The bark is gray to reddish-brown, scaly, often
fissured, and shiny on older plants.
Similar species:
Ecology:
Distribution: This genus is native in North America, Europe and Asia.
Cultivated varieties often escape from cultivation and become naturalized.
Habitat: Crabapples are cold hardy. They thrive in all types of fertile soil. A position in full sun is required for good flower and fruit production. The prairie or Iowa crab (M. ioensis) grows in open woods, wood edges, prairie remnants and abandoned pastures throughout Iowa, except in the extreme northwest parts of the state. Certain cultivars are more disease- and pest-resistant than others; the Asiatic forms are more resistant than the native forms. This genus is susceptible to many pests and diseases, including apple scale, cedar-apple rust, fire blight, powdery mildew, aphids, leafhoppers and apple borers. Rusts and mildews lead to unattractive foliage, defoliation, and sometimes death in wet years.
Uses:
Wood: The red-brown heartwood is heavy, hard, diffuse-porous
and fine-textured. It is used to some extent for tool handles.
Wildlife: The genus Malus is an important source of food for many mammals and birds that disperse the seeds as a result of their feasting. The fruits are relished by many birds, including cedar waxwings, mockingbirds, robins, pheasant and quail. Deer are attracted to abandoned orchards, and rabbits and mice eat the bark and saplings.
Horticulture: Although the fruits make excellent jellies, these trees are usually grown for the showy flowers and ornamental qualities of the fruit. Straggly specimens may be pruned immediately after flowering (if at all), but before early June, as the next season's flowers form from mid June to early July. Because they hybridize so readily, there are probably over 600 types in the US. A large variety of crabapples are well suited to Iowa. Local nursery staff can advise on flower color, single or double forms, fruit size, edibility, persistence on the tree, and degree of disease resistance. The Betchel's crab (M. ioensis 'Plena') is one of the most beautiful flowering crabs, but is susceptible to rust. It grows to 30 feet, has deep pink buds, opening to single, white, fragrant flowers.
