The hawthorns (Crataegus) are a large group of trees hailing from the Rose family that grow native to many parts of North America in the wild. Recognizing a tree as a hawthorn begins with knowing the size, features and traits of these potential ornamentals. Hawthorns bear fruit, which is edible in some instances and will attract wildlife to your property. According to the "National Audubon Society Field Guide to Trees: Eastern Region," some 30 species of wild hawthorn trees are native to the eastern United States alone.
Look for a small tree that in many cases is no larger than a tall shrub. Hawthorns typically grow between 20 and 40 feet, with most at the small end of that scale. For example, the pear, scarlet and Kansas hawthorns grow only to 20 feet, while the downy hawthorn develops to 40 feet. Their size makes the hawthorn trees employable as hedges, specimen plants and screens.
Observe the trunk of a hawthorn tree, looking for grayish to brownish colored bark that usually has a scaly texture. Hawthorn trees have very hard and dense wood, with the trunks of the mature hawthorns appearing to have "muscles." These ridges, along with the tree's fluted façade, add to the hawthorn tree's ornamental worth.
Examine the foliage on a hawthorn tree, looking for leaves that are normally just 2 to 3 inches in length. The leaves of the hawthorn species come in varied shapes. Some are round, other elliptical, while still others may be oval. The edges of the leaves often have deep indentations that will remind you of the teeth on a saw. The green hawthorn leaves will change color in autumn. Some species, including cockspur hawthorn, have excellent fall color, turning shades of orange and scarlet in the fall.
Study the twigs of hawthorn trees, looking for thorns. Sharp, slender thorns are a feature of almost all hawthorn trees, making it necessary to pay close attention when handling a specimen or mowing around one. A fine coating of tiny hairs is often a feature of the immature hawthorn twigs, such as those found on the yellow hawthorn tree.
Inspect the flowers that develop in clusters called cymes on the hawthorn trees in the middle of spring. The flowers possess five petals, are usually white and some give off a somewhat pungent aroma. The flowers bloom in flat-topped groupings once the leaves are on the twigs. The flowers yield a fruit resembling a shrunken-down apple. The fruit is often mealy, reddish and has a diameter up to 1 inch.