When one is choosing a species of crab apples, there are many fine ones available. The Siberian and Southern crab apples are ornamental. Yet, their fruits are excellent for culinary purposes.
Siberian crab (Malus baccata)
Native to eastern Asia, this has become a popular tree in Europe and elsewhere. It has often served as a rootstock for cultivated apples. It is susceptible to fire blight and scab. This was introduced prior to 1800.
It is a vigorous, wide spreading, upright rounded tree. With dense branching, it is among the taller crabs and typically reaches 20 feet in height. Under good conditions, it is 40 to 50 feet tall. Hardy to zones three through seven, it is unharmed by late spring frosts.
The deep green, toothed foliage is 3½ inches in length. Very floriferous, this tree is especially lovely when in full bloom. The fragrant white blooms open mid to late spring. Pink in bud, these are 1½ inches across.
Ripening in late August, the bright red or yellow fruits are good enough to eat fresh. These are less than an inch across. The unripe fruits are made into a cooking vinegar called verjuice.
Southern Crab (Malus angustifolia)
Native to Eastern North America, this is also called wild sweet crab and narrow leaf crab. It is found along the coastal plain from New Jersey southward to Louisiana and westward to Texas. Susceptible to cedar-apple rust, it is recommended for zones six through nine. This does particularly well in the South, and likes acid soils. Typically in the wild it occurs in open woods and along rivers. It can eventually form thickets.
This small spreading to broad, rounded tree can have an irregular shape. Reaching 20 to 30 feet in height, it can be shrubby or tree-like. Rather short-lived, it has slender, thorny branches.
The narrow, oblong foliage is toothed, up to three inches long. It can be lobed. In some areas, this will be semi-evergreen. Pink in bud, the single white to rose colored blossoms are sweetly fragrant. These are 1¼ inch in diameter.
The fruits are almost round, over an inch in diameter. These ripen to yellow-green. These crabs are firm with a tart flavor. They’re used for preserves, jelly, sauces, and pickles.