Hickory tree: how to identify the main species, which nuts are edible, and where hickories grow

At a glance

What a hickory tree looks like

Hickories are tall, straight-trunked hardwoods of eastern forests. Four features confirm the genus before you worry about species:

• Alternate, pinnately compound leaves with an odd number of leaflets, typically 5, 7 or 9 (pecan has more). The end leaflet and the leaflets near the tip are the largest. Michigan State University Extension points to this graduated leaflet size as the way to separate hickory from ash, whose leaflets are narrower and similar in size.
• Alternate buds and leaves. Ash, the most common compound-leaved look-alike, has opposite leaves and buds.
• Solid pith. Split a twig lengthwise: hickory pith is solid, while walnut and butternut pith is divided into small chambers.
• Nut in a sectioned husk. On most hickories the husk splits into four sections at maturity (shellbark's thick husk has five or six). Walnut husks do not split into neat sections.

Hickories are mostly slow-growing and develop a long taproot, which the Morton Arboretum notes makes them difficult to transplant.

Hickory species compared

Shagbark hickory (Carya ovata)

The easiest hickory to name. NC State Extension describes the bark of older trees separating into narrow, flat plates 1–3 feet long that curve away from the trunk, which gives the shaggy look. Leaves carry 5–7 leaflets with the end leaflet largest, and Morton Arboretum notes a hairy terminal bud about an inch long. The nuts are sweet; Michigan State University Extension calls shagbark a tasty local nut and a substitute for pecans. Zones 4–8 (NC State Extension).

Shellbark hickory (Carya laciniosa)

Shaggy-barked like shagbark but, per the Morton Arboretum, with seven to nine leaflets, a thick husk in five or six sections around the largest nut of any native hickory (about 2.5 inches), and a preference for wet bottomland sites.

Pignut hickory (Carya glabra)

A tight-barked hickory. NC State Extension describes smooth bark on young trees that develops flat, sharp-edged ridges forming diamonds and X shapes with age. The name glabra refers to its hairless leaves and twigs; leaves carry 5–7 leaflets. The small oval nut sits in a thin husk about an inch long, and the kernel can be bitter.

Mockernut hickory (Carya tomentosa)

The hairy hickory: the Morton Arboretum notes the underside of the leaf and the leaf stalk are both hairy. Leaves have seven to nine leaflets, the bark is gray, furrowed and shallowly ridged, and the edible nut sits in a thick husk that splits into four. It tolerates dry sites fairly well.

Bitternut hickory (Carya cordiformis)

The Morton Arboretum points to its bright yellow terminal buds, showy all winter, as the standout feature. Leaves carry 7–11 lance-shaped leaflets, the bark has tight, narrow gray-green ridges, and the thin-shelled nut is bitter and inedible. It is common in low, wet areas but also grows on dry uplands.

Pecan (Carya illinoinensis)

The hickory grown for nuts commercially and, per NC State Extension, the largest of the hickories, usually 70–100 feet tall. It is native to the central and east-central U.S. and Mexico. Pecan has 9–17 leaflets whose midribs may curve. Growing it for nuts is its own subject; see pecan tree care.

Hickory look-alikes

Identifying hickories in winter

Bark and buds do the work when leaves are down. Bitternut's bright yellow buds are the fastest winter identification of any hickory. Shagbark and shellbark have terminal buds about an inch long, shagbark's hairy (Morton Arboretum). Fallen husks under the tree help too: Michigan State University Extension notes that only shagbark has a thick husk that pops off in quarters, while other local hickories have thinner, leathery husks that are hard to separate from the nut. Compare trunks with how to identify a tree from bark alone.

Hickory nuts: which ones you can eat

Taste ranges from excellent to unpleasantly bitter:

• Sweet and worth gathering: shagbark and pecan (NC State Extension), plus shellbark, whose large nuts the Morton Arboretum lists as edible. Michigan State University Extension recommends shagbark nuts in place of pecans in any recipe.
• Edible but variable: mockernut (edible, per the Morton Arboretum) and pignut, whose kernel NC State Extension says can be bitter.
• Bitter: bitternut, which the Morton Arboretum calls bitter and inedible. MSU Extension describes both pignut and bitternut nuts as extremely bitter, so confirm the species before you collect.

Per MSU Extension, shagbark nuts are ripe only once they have fallen. The thick husk usually comes off in four quarters; if it sticks, let the nuts dry for about a week and try again. The shell is very hard, and gently tapping with a hammer works better than a typical nutcracker. Discard nuts with holes: pecan weevil, which NC State Extension lists as an occasional pest of shagbark and pignut, develops inside the nuts.

Wildlife value is high: NC State Extension notes shagbark nuts are valued by wildlife, and MSU Extension calls them an important food for small mammals, so expect competition from squirrels.

Where hickory trees grow and how to grow one

Hickories are native to eastern and central North America; pecan reaches into Mexico. Shagbark grows in zones 4–8 per NC State Extension; pignut, bitternut and pecan reach zone 9. They grow in full sun or partial shade in deep, well-drained soils for most species, while shellbark and bitternut tolerate wet bottomlands.

Planting: because of the long taproot, start with a small container-grown seedling or sow nuts where the tree will stay. The Morton Arboretum advises transplanting bitternut in spring only. Keep the root flare at grade and water regularly while the tree establishes. Details are in how to plant a tree the right way.

From seed: collect sound, fallen nuts in fall and sow them outdoors so winter cold breaks dormancy. Protect the planting with hardware cloth; squirrels find buried nuts quickly.

Patience: NC State Extension notes a shagbark may take 40 years to produce nuts but can live 200 to 300 years. Plant for the next generation.

Juglone: hickories share the walnut family with black walnut, the tree best known for juglone toxicity; the Morton Arboretum lists shagbark, shellbark, mockernut and bitternut as tolerant of black walnut toxicity. See black walnut tree care if you are planting near walnut.

Hickories in the landscape, and common problems

A mature hickory is a handsome, long-lived shade tree with golden fall color and, on shagbark, year-round bark interest. The trade-offs are practical: the Morton Arboretum notes that fruit debris drops from late summer through autumn, so keep hickories away from patios, driveways and parking spots, and leave room for a large tree.

• Insects: NC State Extension reports no serious problems for shagbark or pignut, but hickory bark beetle, pecan weevil and twig girdler can be problems in some areas, and borers on pignut. Drought-stressed trees are the most vulnerable to bark beetles and borers; see tree borer damage by gallery pattern.
• Diseases: NC State Extension lists anthracnose, leaf blotch, powdery mildew, leaf spot, cankers and heart rot as occasional diseases of pignut hickory.
• Soil compaction: the Morton Arboretum notes mockernut is sensitive to compacted soils. Protect the root zone out to the drip line during construction or regrading.

Hickory wood

NC State Extension notes pignut hickory wood is valued for its strength, and shagbark wood has many uses, including smoking and curing meat. Michigan State University Extension rates hickories of any species among the best fuelwoods, at around 16 million BTUs per cord, and notes the wood's fragrance makes it ideal for smoking meats.

Common mistakes

Frequently asked

What does a hickory tree look like?

A hickory is a tall, straight hardwood with alternate compound leaves of usually 5 to 9 leaflets, the end leaflet largest. Bark ranges from the shaggy, curving plates of shagbark and shellbark to the tight diamond ridges of pignut. In fall, round nuts in thick or thin husks, usually splitting into four sections, drop beneath the tree.

Can you eat hickory nuts?

Yes, for some species. Shagbark and pecan nuts are sweet, shellbark and mockernut nuts are edible, and Michigan State University Extension recommends shagbark nuts in place of pecans. MSU Extension calls pignut and bitternut nuts extremely bitter, and the Morton Arboretum calls bitternut inedible. Discard nuts with holes, which usually mean weevils.

How do you identify a hickory tree by its bark?

Shagbark and shellbark hickory have long, flat gray plates that curve away from the trunk; MSU Extension notes no other hickory in Michigan has that bark. Pignut develops flat, sharp-edged ridges forming diamonds, mockernut is gray, furrowed and shallowly ridged, and bitternut has tight, narrow gray-green ridges. Young pignut bark is smooth and young shagbark is scaly, so check leaves or buds too.

Where do hickory trees grow?

Hickories are native to eastern and central North America, with shagbark ranging from southern Ontario and Quebec to Texas, Georgia and the Dakotas, and pecan reaching south into Mexico. Shagbark is common in upland woodlands and savannas, mockernut tolerates dry sites, and shellbark and bitternut favor wet bottomlands and low areas.

Is hickory good firewood?

Yes. Michigan State University Extension rates hickories of any species among the best fuelwoods, producing around 16 million BTUs per cord when seasoned. Split it and let it dry before burning, as with any hardwood. The wood's fragrance also makes it a favorite for smoking meat.

How long do hickory trees live?

Hickories are slow-growing, long-lived trees. NC State Extension notes a shagbark hickory may take 40 years to produce nuts but can live 200 to 300 years.

How do you tell hickory from ash?

Check leaf arrangement first: hickory leaves and buds alternate along the twig, while ash leaves and buds are opposite in pairs. Michigan State University Extension notes hickory leaflets are much larger near the tip of the leaf, while ash leaflets are narrower and similar in size. Ash fruit is a narrow single-winged samara, not a nut.

Sources

1. Carya ovata (shagbark hickory), NC State Extension Gardener Plant Toolbox
2. Carya glabra (pignut hickory), NC State Extension Gardener Plant Toolbox
3. Carya illinoinensis (pecan), NC State Extension Gardener Plant Toolbox
4. Shagbark hickory, The Morton Arboretum
5. Shellbark hickory, The Morton Arboretum
6. Mockernut hickory, The Morton Arboretum
7. Bitternut hickory, The Morton Arboretum
8. Shagbark hickory: another tasty local nut, Michigan State University Extension

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