An apple (Malus) is considered a crabapple if the diameter of its fruit is 2 inches (5 cm) or less. There are some 20-30 crabapple species. Crabapples are usually cross-fertile and freely hybridize, a plant breeders dream. The number of crabapple types (cultivars) is unknown, but it may be near 900, according to T. L. Green (Amer. Horticulturist. Feb., 1996), and some 200 are available from nursery sources. About 50 crabapples are listed in the Oregon Association of Nurserymen Buyers Guide. Crabapples are especially popular in the Midwest and eastern US. They are adaptable to varying soil conditions, but do best in a heavy loam that is well drained, moist, and acidic. Common diseases and insect pests include fireblight, cedar apple rust, apple scab, powdery mildew, canker, scale, borers, and aphids.
Malus: the Latin name for apple.