Identifying characteristics:
Authors have named over 1000 species of hawthorns but identification
of the various species is difficult as hybridization is common. Hawthorns
are small trees (or shrubs in poor soil), usually growing to 25 feet tall,
but some species reach 40 feet. The trunk is often twisted or multistemmed,
and the crown rounded and spreading. The outline is often rugged and picturesque,
especially in winter. The twigs are often zigzag and armed with long, shiny,
unbranched, sharp thorns. Leaves
are simple, alternate, serrated or shallowly lobed in most species. Fall
color can be red, yellow, orange or purple. Flowers
occur in showy flat-topped clusters in late spring after the leaves, and
colors range from white through pink, to red. Often the flowers have a sweet,
fetid odor. The fruit is a small,
attractive, edible pome, called a "haw" or "thorn apple,"
with 1 to 5 nutlike seeds. The taste, texture and color varies, but haws
can be red, yellow, green or black, and usually they are dry and mealy but
can be sweet and juicy. The small leaf scars are crescent-shaped
with 3 bundle scars. Buds are roundish, with about 6 fleshy,
reddish scales. The reddish-brown to gray bark
is scaly or shallowly furrowed, sometimes with branched thorns on the trunk.
Similar species:
Ecology:
Distribution: Hawthorns are native to North America, Mexico,
South America, Europe and Asia. They are native to Iowa and are planted
throughout the state.
Habitat: Hawthorns are common to bottomlands and disturbed upland sites. They are intolerant of shade and, though slow-growing, are aggressive invaders of pastures, prairies and abandoned fields near woods. They will grow in a variety of soils, but occur particularly on calcareous soils. Being members of the rose family, hawthorns are susceptible to many pests and diseases. Cedar hawthorn leaf rust is problematic to many hawthorn species. This disease spreads to hawthorns from the eastern red cedar (Juniperus virginiana) and other cedars.
Uses:
Wood: "Crataegus" is derived from the Greek word
for strength. The wood is tough, hard, heavy, close-grained and diffuse-porous.
Although trees are too small and crooked to be of commercial value to the
timber industry, the wood is sometimes used for tool handles, canes, small
turned objects and fuel.
Wildlife: The fruits are not used by wildlife as much as we might expect. Only a few species of birds like the fruits and so they remain ornamental for a long period of time. Pheasants, cedar waxwings, robins, fox squirrels, raccoons, squirrels and skunks feed on the fruit. Birds nest in the trees, taking advantage of the thick foliage and thorniness. Deer browse the young twigs and leaves.
Horticulture: Hawthorns are frequently used in landscaping for their ornamental habit and showy flowers and fruits. The downy hawthorn (C. mollis), our most common native species, is discussed elsewhere in this booklet. The cockspur hawthorn (C. crus-galli) is the specimen indicated on the map. It is a native of Iowa and grows to 25 feet tall with white flowers, red fruits and long thorns. It is susceptible to cedar hawthorn leaf rust and leaf blotch miner. The dotted hawthorn (C. punctata) is a horizontally-branching Iowa native with red to yellow fruits and white flowers, growing to 25 feet tall. The Washington hawthorn (C. phaenopyrum), though hardy to Iowa, is native to the southeastern US. The English hawthorn (C. oxycantha) and the single-seed hawthorn (C. monogyna) are two Eurasian species often planted as ornamentals in Iowa.
