American Hazelnut is a native erect perennial shrub.
Stems: It grows in rounded form up to 11 feet high with erect branches and while each plant will have one central stem, it will also send up multiple auxiliary stems from the extensive shallow root system.
Bark is smooth, light gray in color. As it ages a scaly crisscross pattern forms.
Twigs grow in a zigzag pattern, are light brown in color, hairy with glandular hairs. Buds have blunt tips with just a few scales, darker color than the twig. Leaves are alternate and simple, broadly oval in shape, up to 5 inches long, with margins sharply cut into double teeth. The dark green tops contrast with the paler undersides which have fine hair and longer white hair on the veins. Young leaves are densely hairy even on the margins. Leaves have short stiff hairy stalks, rounded or heart-shaped bases. Fall color can be extremely variable from yellow to red and purple.
Flowers: The plant is monoecious (separate male and female flowers). The male flowers are very conspicuous light brown catkins, 2 to 5 inches long, appearing in a cluster of 2 or 3 on the sides of small branches near the branch tips opening before the leaves appear. These appear on the branches in the fall but open in the spring. The male flowers on the catkin have 4 stamens surrounded by two small bracts. The female flowers are quite small, with several rising from what appears to be a bud near the end of a twig in early spring. Only the stigma and styles protrude, looking like thin red threads.
Fruit: After pollination by the wind, the male flowers wither away and the pollinated female flowers mature to a 1/2 inch diameter edible brown nut that is enclosed in a leaf-like hairy bract that has ragged edges. This is green initially, becoming brown at maturity. Nuts will usually be in a cluster of 2 to 5.
Habitat: American Hazelnut grows from a rhizomatous root system, forming thickets and is best in rich moist well drained soils with full to partial sun. It will tolerate full shade but nut production may be subdued and the stems will be taller and sparser. It propagates primarily by offsets from the root system forming thickets and colonies. Nuts can be produced after the first year. Look for it in open woods, thickets and exposed wood margins.
Names: The common name of hazelnut is derived from 'hazel', the old English name for filbert. The plant has been cultivated the U.S. since the late 1700s and there are several varieties available for commercial nut production. The genus, Corylus, is derived from the Greek word 'korus', meaning 'helmet' and refers to the shape and hardness of the nut shells. The author name for the plant classification, ‘Walter’ is for Thomas Walter (1740-1789) British born American botanist, best know for his 1788 catalogue of plants of South Carolina, Flora Caroliniana.
Comparisons: The close relative of this species is Beaked Hazelnut, C. cornuta. It has similar leaves and flowers but the fruit has a long tubular beak completely hiding the nuts.
Above: American Hazelnut flowers: 1st photo - the male catkin about to open its flowers. 2nd photo - The small female flowers with only the stigmas and styles protruding. 3rd photo - Twigs and leaf stalks have many glandular hairs. Note the light brown color of the twigs.
Below: Two more examples of female flowers.
Below: Flower detail. 1st photo- a group of male catkins with flowers open. 2nd photo - The individual male flower has 4 stamens surrounded by 2 light green bracts. Note the small bud on the twig with the styles of the female flower protruding.
Below - Leaves: Leaves are broadly oval with a double row of teeth. Fall leaf color can be a brilliant reddish before changing to a darker purple. Note in 2nd photo the male catkins are already formed for next spring.
Below: The leaf underside is paler in color due to fine hair, with longer white hair on the veins. Older stems develop a more scaly bark.
Below: Young leaves are densely hairy including the margins. 2nd photo - seed clusters forming.
Below - Fruit development: 1st photo - Fruit maturing with the distinguishing ragged edge leafy bract covering the nuts. 2nd photo - Mature seed capsule containing three brown nuts.
Below: A spring twig before the appearance of the glandular hair. Bud scales can have fine hair.
Below: 1st photo - The male catkins for next years flowers are formed in the autumn and elongate and open the flowers in the spring of the following year. 2nd photo - The fall color of the leaves of American Hazelnut ranges from yellow to reddish to purple. Note the male catkins hanging from the branches.
Below: American Hazelnut can make a nice smaller shrub - as wide as tall it some pruning is done, otherwise the natural shape, while rounded, can be taller and leggy.
Notes: American Hazelnut is indigenous to the Garden. Eloise Butler catalogued it on April 29, 1907. It has been listed on all subsequent census reports. Garden Curator Susan Wilkins added additional plants in 2008 and 2015. In North America the plant ranges from the mid-continent east to the coast, excepting Texas and Florida and the Canadian maritime provinces. There are only 3 species of Corylus native to North America. Two are found in Minnesota, this one and C. cornuta, the Beaked Hazelnut. The third species is found on the west coast and called the California Hazelnut, C. cornuta Marshall var. californica.
Uses: The nuts are sweet and similar to the European Filbert and have long been used for eating or grinding up into meal to make a cake-like bread. Flavor is similar to the two commercial varieties, C. colurna and C. maxima Mill. Great numbers of wildlife species also benefit from this plant in the wild.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"