Mockernut Hickory (Carya tomentosa)

Mockernut hickory is the most abundant of the hickories and has a long life span of up to 500 years. The nuts from this tree are edible, and the wood is considered by many to be the best of all hickories and is frequently used to make rustic furniture.

I. Appearance and Characteristics

Carya tomentosa, commonly known as mockernut hickory, mockernut, white hickory, whiteheart hickory, hognut, bullnut, is a species of tree in the walnut family Juglandaceae. The most abundant of the hickories, and common in the eastern half of the United States, it is long lived, sometimes reaching the age of 500 years. A straight-growing hickory, a high percentage of its wood is used for products where strength, hardness, and flexibility are needed. The wood makes excellent fuel wood, as well. The leaves turn yellow in Autumn.

The species’ name comes from the Latin word tomentum, meaning “stuffing”, referring to the underside of the leaves, which are covered with dense, short hairs, which help identify the species. Also called the white hickory due to the light color of the wood, the common name mockernut likely refers to the would-be nut eater, who would struggle to crack the thick shell only to find a small, unrewarding nut inside.

• Flowering and fruiting

Mockernut hickory is monoecious – male and female flowers are produced on the same tree. Mockernut male flowers are catkins about 10 to 13 cm (3.9 to 5.1 in) long and may be produced on branches from axils of leaves of the previous season or from the inner scales of the terminal buds at the base of the current growth. The female flowers appear in short spikes on peduncles terminating in shoots of the current year. Flowers bloom in the spring from April to May, depending on latitude and weather. Usually the male flowers emerge before the female flowers. Hickories produce very large amounts of pollen that is dispersed by the wind.

Fruits are solitary or paired and globose, ripening in September and October, and are about 2.5 to 9.0 cm (0.98 to 3.54 in) long with a short necklike base. The fruit has a thick, four-ribbed husk 3 to 4 mm (0.12 to 0.16 in) thick that usually splits from the middle to the base. The nut is distinctly four-angled with a reddish-brown, very hard shell 5 to 6 mm (0.20 to 0.24 in) thick containing a small edible kernel.

• Seed production and dissemination

The seed is dispersed from September through December. Mockernut hickory requires a minimum of 25 years to reach commercial seed-bearing age. Optimum seed production occurs from 40 to 125 years, and the maximum age listed for commercial seed production is 200 years.

Good seed crops occur every two to three years with light seed crops in intervening years. Around 50 to 75% of fresh seed will germinate. Fourteen mockernut hickory trees in southeastern Ohio produced an average annual crop of 6,285 nuts for 6 years; about 39% were sound, 48% aborted, and 13% had insect damage. Hickory shuckworm (Laspeyresia caryana) is probably a major factor in reducing germination.

Mockernut hickory produces one of the heaviest seeds of the hickory species; cleaned seeds range from 70 to 250 seeds/kg (32 to 113/lb). Seed is disseminated mainly by gravity and wildlife, particularly squirrels. Birds also help disperse seed. Wildlife such as squirrels and chipmunks often bury the seed at some distance from the seed-bearing tree.

• Seedling development

Hickory seeds show embryo dormancy that can be overcome by stratification in a moist medium at 1 to 4 °C (33° to 40 °F) for 30 to 150 days. When stored for a year or more, seed may require stratification for only 30 to 60 days. Hickory nuts seldom remain viable in the ground for more than a year. Hickory species normally require a moderately moist seedbed for satisfactory seed germination, and mockernut hickory seems to reproduce best in moist duff. Germination is hypogeal.

• Rooting habit

True hickories such as mockernut develop a long taproot with few laterals. Early root growth is primarily into the taproot, which typically reaches a depth of 30 to 91 cm (12 to 36 in) during the first year. Small laterals originate along the taproot, but many die back during the fall. During the second year, the taproot may reach a depth of 122 cm (48 in), and the laterals grow rapidly. After 5 years, the root system attains its maximum depth, and the horizontal spread of the roots is about double that of the crown. By age 10, the height is four times the depth of the taproot.

II. How to Grow and Care

Climate

The climate where mockernut hickory grows is usually humid. Within its range, the mean annual precipitation measures from 890 mm (35 in) in the north to 2,030 mm (80 in) in the south. During the growing season (April through September), annual precipitation varies from 510 to 890 mm (20 to 35 in). About 200 cm (79 in) of annual snowfall is common in the northern part of the range, but snow is rare in the southern portion.

Annual temperatures range from 10 to 21 °C (50 to 70 °F). Monthly average temperatures range from 21 to 27 °C (70 to 80 °F) in July and from -7 to 16 °C (20 to 60 °F) in January. Temperature extremes are well above 38 °C (100 °F) and below −18 °C (0 °F). The growing season is about 160 days in the northern part of the range and up to 320 days in the southern part of the range.

Sunlight

Mockernut hickory plants are adaptable to grow in partial shade to full sun. However, it grows the best with full sunlight which means at least 8 hours of sunshine should be received.

Watering

Keep regularly watering the newly planted plants after your first watering while transplanting. Once established, mockernut hickory is drought tolerant, however, it is necessary to provide them 2.5 cm of water per week under dry and high-temperature conditions.

Soil

Mockernut hickory can grow on a variety of soil conditions including moist sandy, loamy and clay soils, from moderately acidic to alkaline. But they perform superbly in moist, rich, slightly acidic to neutral (pH 6.1-7.3), silty loam that is well-drained.

Fertilizing

While transplanting, an application of slow-release fertilizer is recommended to enhance root establishment and favor early growth. Fertilizer for the established plants may be calculated on the basis of their truck diameter, you should follow the guide or manual of your fertilizer. Only notice that when you measure the trunk diameter, measure at a height of 1.3 m. Spread fertilizers evenly under the canopy once or twice a year in early spring and/or fall.

Planting Instructions

You can start your mockernut hickory planting with either seeds or saplings. However, as mockernut hickory is a medium- to slow-growing tree, it is recommended to plant saplings bought from a nearby nursery or gardening store. The excellent growth of mockernut hickory is observed on raised beds with adequate moisture. You can make raised beds that fit the size of the root ball of the saplings for transplanting.

Prepare beds by digging deep earth up, loosening and mixing with the garden soil at a sunny location. Multiple trees should be spaced 6 to 7 m between the rows if grown in the orchards or as open field cultivation. What you should know is, none of Carya species are suitable for containers due to their deep, straight root system. You can only grow mockernut hickory in your garden or orchard.

Pruning

Generally, pruning is not a necessity of mockernut hickory but light pruning throughout the year can improve the light reception of inner foliage. Trimming is favored for the newly grown plants as well, which promotes growth. Don’t mess the main truck, just remove weak, broken and dead twigs on the secondary branches when noticed.

Propagation

If you want to propagate mockernut hickory yourself, collect nuts on maturity in fall when they begin to fall. Soak the seeds (nuts with the hard outer shell) in water for 2-4 days to adapt to stratification. They need 3-4 months of cold stratification (at 1 to 4 ℃) to break dormancy priorly. Then the seeds can be planted directly into the garden in fall, or one seed per deep pot, from 2.5 to 4 cm deep in the soil. Shelter a 5 to 8 cm layer of straw to protect garden ones from frosting effects. After sprouting, keep them fully shined and soil moist but not over-watered for 6-8 weeks to develop an extensive root system for further transplants when needed.

Damaging agents

Mockernut hickory is extremely sensitive to fire because of the low insulating capacity of the hard, flinty bark. It is not subject to severe loss from disease. The main fungus of hickory is Poria spiculosa, a trunk rot. This fungus kills the bark, which produces a canker, causes heart rot and decay, and can seriously degrade the tree. Mineral streaks and sapsucker-induced streaks also degrade the lumber. In general, the hard, strong, and durable wood of hickories makes them relatively resistant to decay fungi. Most fungi cause little, if any, decay in small, young trees.

Common foliage diseases include leaf mildew and witches’ broom (Microstroma juglandis), leaf blotch (Mycosphaerella dendroides), and pecan scab (Cladosporium effusum). Mockernut hickory is host to anthracnose (Gnomonia caryae).

Nuts of all hickory species are susceptible to attack by the hickory nut weevil (Curculio caryae). Another weevil (Conotrachelus aratus) attacks young shoots and leaf petioles. The Curculio species are the most damaging and can destroy 65% of the hickory nut crop. Hickory shuckworms also damage nuts.

The bark beetle (Scolytus quadrispinosus) attacks mockernut hickory, especially in drought years and where hickory species are growing rapidly. The hickory spiral borer (Argilus arcuatus torquatus) and the pecan carpenterworm (Cossula magnifica) are also serious insect enemies of mockernut. The hickory bark beetle probably destroys more sawtimber-size mockernut trees than any other insect. The hickory spiral borer kills many seedlings and young trees, and the pecan carpenterworm degrades both trees and logs. The twig girdler (Oncideres cingulata) attacks both small and large trees; it seriously deforms trees by sawing branches. Sometimes, these girdlers cut hickory seedlings near ground level.

Severe damage to hickory lumber and manufactured hickory products is caused by powderpost beetles (Lyctus spp. and Polycanon stoutii). Gall insects (Caryomyia spp.) commonly infest leaves. The fruit-tree leafroller (Archips argyrospila) and the hickory leafroller (Argyrotaenia juglandana) are the most common leaf feeders. The giant bark aphid (Longistigma caryae) is common on hickory bark. This aphid usually feeds on twigs and can cause branch mortality. The European fruit lecanium (Parthnolecanium corni) is common on hickories.

Mockernut is not easily injured by ice glaze or snow, but young seedlings are very susceptible to frost damage. Many birds and animals feed on the nuts of mockernut hickory. This feeding combined with insect and disease problems eliminates the annual nut production, except during bumper seed crop years.

III. Uses and Benefits

• Ornamental uses

A big, impressive tree that needs a lot of room to grow, mockernut hickory is generally planted by gardeners who have a big yard or lawn and want an imposing and good-looking tree that is fairly easy to care for. It is usually planted as a shade tree or the focal point of a lawn or garden, and can also be used as the canopy for a shade garden.

• Wildlife uses

Mockernuts are a preferred mast for wildlife, particularly squirrels, which eat green nuts. Black bears, foxes, rabbits, beavers, and white-footed mice feed on the nuts, and sometimes the bark. The white-tailed deer browse on foliage and twigs and also feed on nuts. Hickory nuts are a minor source of food for ducks, quail, and turkey.

Mockernut hickory nuts are consumed by many species of birds and other animals, including wood duck, red-bellied woodpecker, red fox, squirrels, beaver, eastern cottontail, eastern chipmunk, turkey, white-tailed deer, white-footed mice, and others. Many insect pests eat hickory leaves and bark.

Mockernut hickories also provide cavities for animals to live in, such as woodpeckers, black rat snakes, raccoons, Carolina chickadees, and more. They are also good nesting trees, providing cover for birds with their thick foliage. Animals help disperse seeds so that new hickories can grow elsewhere. Chipmunks, squirrels, and birds do this best. Some fungi grow on mockernut hickory roots, sharing nutrients from the soil.

• Other uses

True hickories provide a large portion of the high-grade hickory used by industry. Mockernut is used for lumber, pulpwood, charcoal, and other fuelwood products. Hickory species are preferred species for fuelwood consumption. Mockernut has the second-highest heating value among the species of hickories. It can be used for veneer, but the low supply of logs of veneer quality is a limiting factor.

Mockernut hickory is used for tool handles requiring high shock resistance. It is used for ladder rungs, athletic goods, agricultural implements, dowels, gymnasium apparatus, poles, shafts, well pumps, and furniture. Lower-grade lumber is used for pallets, blocking, etc. Hickory sawdust, chips, and some solid wood are often used by packing companies to smoke meats; mockernut is the preferred wood for smoking hams. Though mockernut kernels are edible, they are rarely eaten by humans because of their size and because they are eaten by squirrels and other wildlife.

IV. Harvesting and Storage

Notice that only mockernut hickory trees older than 10 years start producing nuts. Harvest in fall when the brown, readily ripe nuts drop down on the ground. If the ripe nuts still stay on the tree, a gentle shake can promote free falls onto the ground. Pick the nuts from the ground before rodents and birds, remove the remaining husks and store the nuts with the outer shell where cool and dry if you are not eating them immediately. You can also crack the outer shell and store the meat of the nut by refrigerating or freezing.

Find Where to Buy the Best Mockernut Hickory (Carya tomentosa)

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