Hawthorn (Crataegus species)

A group of deciduous trees and shrubs from the Rose Family (Rosaceae)

Hawthorns comprise the single largest group of trees and large shrubs that inhabit the woods and fields of Ohio, based upon the number of native and naturalized species (more than 60), even outnumbering the Oaks (over 20). They are known primarily for their white spring flowers, late summer and autumn fruits (yellow, orange, or red in color), and their twiggy, thorny canopies. Growth is usually slow, and their preference is for sunny sites under a variety of soil conditions, tolerating summer drought very well. In general, they have an upright to rounded growth habit in youth, becoming spreading as they mature.

Hawthorns tend to colonize pastures, where their thorns prevent cattle and other domestic animals from grazing on them while they are young or mature. Heights range from 10 to 25 feet, and widths about 15 to 30 feet. As members of the Rose Family, they are related to the Serviceberries, Chokeberries, Crabapples, Plums, Cherries, Pears, and Roses, as well as many other genera of ornamental and economic importance.

Planting Requirements- Hawthorns are very adaptable to a wide range of growing conditions. Most species perform best in average soils of good drainage with an alkaline or neutral pH, but most adapt to soils of an acidic pH. Throughout Ohio, most Hawthorns are winter hardy to zone 5, if not zone 4.

Potential Problems - Hawthorns have a number of diseases and pests that can damage their foliage, fruits, or bark, but most are not lethal. In urban situations, discretion should be used when transplanting them near pedestrian traffic (for thorn liability to exposed skin, eyes, and feet) and near human activity (near windows or shelters where the smell of their spring flowers can be overwhelming).

They are lumped together here as a group because of the difficulty in sometimes determining their exact identification due to similar features (especially in winter), and for the tendency of some members to form natural hybrids, thus further blending their already similar traits.

Leaf Identification Features

The leaves of the many species and hybrids of Hawthorns vary greatly in shape. Those of Dotted Hawthorn (Crataegus punctata) are distinctive in that they are narrow and obovate, with prominent veins.

Those of many other Hawthorns are approximated by a leaf shape that is ovate with several shallow lobes and many serrations. Fall color is usually green to chartreuse on the many species and their natural hybrids.

Other Identification Features

The perfect flowers of most Hawthorns are very similar in appearance, being clusters of white blossoms from early spring through late spring that vary from being mildly fragrant to extremely malodorous. The example shown is of Green Hawthorn (Crataegus viridis) in mid-spring.

Green fruits that result from the perfect flowers may be pendulous or upright, of yellow, orange, or red coloration when ripe, and are generally larger than those of Washington Hawthorn. The ripened fruits of Crataegus pinnatifida major (which does not have a common name) occur by mid-summer.

Hawthorns are so named by a combination of an alternative name for the fruits (haws) and the plentiful thorns. The thorns are often found singly on the twigs and branchlets, and may be thick or thin, straight or curved. In the case of Cockspur Hawthorn (Crataegus crus-galli), the thorns are single and curved downward from the twigs, but compound and pointing downward or outward from the trunks.

The mature barks of the native Hawthorns are usually scaly to platy, and colored various shades of gray and brown, often with orange or red interior barks. In the case of Green Hawthorn (Crataegus viridis), the outer flaky bark is gray-green, and the inner bark is light orange.