Identifying characteristics:
Hazelnuts are large, multistemmed shrubs with rather straight, spreading
branches forming a round-topped head. The lower portions of the plant are
often leggy and open. They can reach a height of 18 feet, but usually grow
to 8 feet tall, forming large clumps or thickets. The 2- to 6-inch-long
leaves are simple, alternate and broadly-ovate,
with veins running to the tips of the leaves. Leaf margins are coarsely
toothed, and the leaf stalks and twigs are covered with stiff, gland-tipped
hairs. The upper surface is dark green and sparsely hairy, the lower surface
paler and softly hairy. Fall color is yellowish-green with a tinge of red.
Male and female flowers occur separately
on the same plant and are among the first flowers to open in spring. The
showy male catkins are long (to 3 inches), yellowish-brown and drooping.
Female flowers are inconspicuous, apetalous (because they are wind pollinated)
and occur in red buds at the ends of branches. The fruit
is an edible nut produced inside a pair of leathery bracts (involucres).
Bracts are downy, toothed, deeply cut and 1 inch long. The nut is 0.5 inches
long, slightly flattened and matures in September or October. The imbricate
buds are almost globe-shaped, with 4 to 6 greenish-brown scales.
Similar species:
- beaked hazelnut (C. cornuta)
-
Ecology:
Distribution: Hazelnuts are native from New England to Saskatchewan,
south through the Dakotas, Georgia and to Florida. They are native in Iowa.
Habitat: Found in clearings, along wood edges and as an understory shrub in older forests, the hazelnut tolerates full sun or light shade and is adaptable to moist and dry sites. In Iowa it is found in dry, open woods and along wood edges. It tends to sucker from the roots and requires maintenance to remain respectable as a yard specimen. This species is not affected by any serious pests. Mildew may defoliate plants and fungi may destroy nuts. Gall gnats may attack catkins. Several canker-forming fungi may result in girdling or breakage of stems.
Uses:
Wildlife: This species is closely related to the European filbert
(C. avellana). The nuts are not only relished by humans, but also
by squirrels, foxes, woodpeckers and small rodents. Their nutritional value
is higher than that of acorns and beechnuts. Turkey and grouse eat the buds,
catkins and nuts, and hoofed browsers and rabbits eat the foliage and twigs.
The dense, low growth habit provides cover and nesting sites for many species
of wildlife.
Horticulture: Hazelnuts are shrubs best suited to naturalized settings as they are large, spreading, suckering plants. Planted in well-drained, loamy soil they may be pruned at any time of the year. The European filbert (C. avellana) and its cultivars are small trees and may be more useful in landscaping. Harry Lauder's walkingstick (C. avellana 'Contorta') is an attractive shrub to 8 feet tall, with twisted, contorted slender branches and leaves, especially effective in spring with bare branches and drooping catkins. The beaked hazelnut (C. cornuta) is a native of northeastern Iowa with a prolonged beak formed by the nut bracts.
