Hickory trees are all part of the Carya genus in the Juglandaceae or Walnut family of flowering trees.
There are 18 currently accepted species of hickory trees native to the northern hemisphere, mostly in the USA but also Canada, Mexico, and eastern Asia.
The highest species diversity is found in the USA, with 12 different types of hickory trees native there and several of those endemic (found nowhere else).
Hickories evolved somewhat recently, between 25 and 53 million years ago, likely in North America since this is where the highest diversity is found.
The most famous hickory tree is the pecan, Carya illinoinensis, famous for its delicious nut. It is native to the southern USA and northeastern Mexico.
All hickory trees produce bountiful edible nuts, many of them pleasant tasting and some very bitter. But all are loved by wildlife, providing them with a nutrient-dense food source.
Hickory Tree Identification (With Photos)
Identifying Hickory Trees by Their Leaves
All hickory trees have compound, deciduous leaves that turn yellow in the fall and return each spring from leaf buds.
A compound leaf is made of two to many leaflets arranged on a central rachis. The rachis is a stalk that the individual leaflets attach to.
In hickories, there are anywhere from 3 – 17 leaflets in an odd-pinnate arrangement. The number of leaflets is a very useful tool in identifying the different types of hickory trees.
Odd-pinnate compound leaves (also called imparipinnate) always have three or more odd numbers of leaflets. There are pair(s) of leaflets on opposite sides of the central rachis, known as lateral leaflets, and one often somewhat larger and sometimes differently shaped terminal leaflet at the tip of the rachis.
The petiole or leaf stalk is what attaches the compound leaf to the twigs or branches. Compound leaves often also have petiolules or small leaf stalks that attach the leaflets to the rachis of the compound leaf.
In the odd-pinnate leaves of hickories, the lateral petiolules are almost always either absent or quite short, typically less than 1/16”. When they are longer, this can be used to help in identification. The terminal petiolule is quite variable; it can be absent, short, or relatively long (1” or more). This can also aid in identification.
Identifying Hickory Trees by Their Leaflet Shape
Hickory leaflets can be ovate (egg-shaped), obovate (like ovate but with the widest part at the tip instead of the base), lanceolate (lance-shaped or narrowly egg-shaped), oblanceolate (lance-shaped but with the widest part at the tip instead of the base), elliptic (like an ellipse widest in the middle and narrower on both ends), or sometimes falcate (hooked towards the tip, asymmetrical).
The shape often varies within species, but it can still sometimes be helpful to identify the different types of hickories.
Similar terminology is used to describe fruit, nut, and bud shapes which are often described as ovoid (like ovate but three-dimensional), obovoid (like obovate), and ellipsoid (like elliptical). These features are also often rounded, which botanists call spherical when three-dimensional or orbicular when referring to a two-dimensional structure, but we will just use rounded here.
Identifying Hickory Trees by Their Leaflet Margins
Hickory leaflets have margins that are almost always serrated, which means jagged-toothed, like a saw. Within species, they are often both finely and coarsely serrated, but sometimes they are only coarsely serrated.
Rarely are margins entire and wavy, which can be used to identify certain species when this is seen.
Identifying Hickory Trees by Their Leaflet Tips
Hickory leaflet tips are not all that variable. They usually have long-pointed tips (acuminate, the tip narrows into a long thin point).
Sometimes they are narrowly acuminate (long-pointed but on a narrower tip with the edges meeting at a very narrower angle) or acute (with more or less straight edges that meet at an angle of less than 90 °). Falcate tips are like long-pointed or acuminate, but they curve asymmetrically to one side.
Identifying Hickory Trees by Hairs and Scales on Surfaces
Hickory leaflets, as well as their buds, twigs, rachis, petioles, and flower stalks, usually have characteristic hairs and scales that are great identification tools used to help determine the different types of hickory trees.
Leaflet surfaces, in particular, often vary considerably throughout the season in hickory trees. Many retain their surface features all year, while many others are hairier and/or scalier in spring but then lose most or all of it by the fall. This can make identification a bit more challenging since you will always need to consider the time of year you are looking at the tree.
Botanists have a lot of terms for hairs used to describe the different sizes, shapes, and feel of those hairs.
Hickory hairs are often hirsute (straight, coarse and stiff, rough to the touch), but they can also be pubescent (soft straight hairs, they often can look like hirsute but are very soft to the touch), puberulent (like pubescent but very short), villous (long soft shaggy hairs, but not matted), pilose (long soft straight hairs), glandular (topped with a gland), or tomentose (long but densely matted hairs). Certain species also have tufts of hairs in the axils of leaf veins, particularly near the serrated teeth.
We call plant hairs ‘hair’ simply because they resemble the hair we see on animals. When you get right down to it, they are not like animal hairs at all. Botanically and morphologically speaking, they are made of entirely different substances and are technically referred to as trichomes.
Hickories also usually have scales that are flat plate or shield-like clusters of trichome cells on the surface of plants that may or may not be attached to the surface by a stalk. They are botanically just like plant ‘hairs’, but because they do not resemble hair, we refer to them as scales.
Scales look like little flat spots on plant surfaces, and they are typically rough to the touch, like a fine grit sandpaper.
We won’t get into the different types of scales here, as that would require a magnifying glass. Still, we will note whether the surfaces are scaly or not and whether those scales impart a characteristic color to the leaf or other plant surface.
Identifying Hickory Trees by Their Flowers
Hickory trees are all monoecious, they produce separate male and female flowers on the same tree.
Their flowers, however, mature at different times, so the anthers are never mature when the female flowers are receptive. This makes them self-incompatible and unable to self-fertilize. This means that you will always need more than one hickory to cross-pollinate if you want to produce fruit.
Hickory flowers are very small and lack petals and usually sepals and instead are simply composed of either male or female reproductive parts and their associated bracts.
Identifying Hickory Trees by Their Female Flowers
Female flowers on hickory trees are made of an ovary that contains ovules (unfertilized seeds) plus a usually green or yellow-green lobed stigma (the receptive surface that receives pollen and directs it into the ovary, usually located below it). They lack the styles (a stalk between the stigma and ovary) that many flowers have.
Female flowers are typically arranged in small clusters of 2 – 4 flowers at the tips of new twigs.
Female flowers do not vary much between species, so they are only rarely used to help identify the different types of hickory trees.
Identifying Hickory Trees by Their Male Flowers
Male flowers contain stamens which are made of filaments (a stalk) with anthers on top that produce and release pollen. In hickories, there are 2 – 10 stamens per flower. They are small and are rarely used much to help in identification except sometimes when noting whether they are hairy or not. But since the hairs can be difficult to see without a magnifying glass, we will rely on other features here.
Male flowers are born in clusters of three yellow-green catkins of varying lengths, which can be quite useful to aid in identification.
Most catkins have noticeable stalks, and their absence can be used to help identify certain species.
The presence or absence of hairs on the stalk holding the catkin can also be used to help determine the different types of hickory trees. They also have characteristic hairs on their bracts, but again, those can sometimes be difficult to see, so we will rely on other features.
Identifying Hickory Trees by Their Fruits
All hickories produce nut-like fruits. Many consider hickory nuts true nuts. Botanically they are much closer to a true nut than a peanut is.
However, while they have a hard shell with a seed inside, like a true nut, they also have a dry protective coating called a husk. This would make them a dry drupe. For comparison, cherries are fleshy drupes that we eat the flesh of. However, this protective coating contains involucral bract tissues not found in other dry drupes. Hence, it is correctly referred to as a pseudodrupe.
However, since only nerdy scientists like me generally care to haggle over this distinction, in this article, we will simply refer to the entire unit as a fruit and the hard shell and seed inside as a nut. It would just be very remiss of me to refer to them as a nut without explaining the facts behind it.
The shape, size, and color of the nuts and their associated rough husks are very useful tools in helping to identify the different types of hickory trees.
The husks are all four-valved, meaning they split open along four lines called sutures. In some species, the sutures are smooth, others are noticeably winged, and some are only slightly winged. The sutures can easily be seen while the fruit is still developing before it splits open.
Sometimes we can look at how far the husk splits down the sutures, a process known in botany as dehiscence. In hickories, most split to the base or nearly so, but occasionally some only dehisce partway or halfway.
The husks can vary considerably in thickness; some are thin, while others can be very thick.
Another feature we can look at is whether the nut is smooth or wrinkled or ribbed, a term often called rugose, but in hickories, it is referred to as rugulose because it is only slightly wrinkled.
Some species’ nuts are not just wrinkled but are very clearly four-angled (rarely two-angled), having four ridges or sides to them, while others have no defined sides.
Some nuts have thinner shells, like pecans, making them easier to crack open. Other nuts have much thicker shells, like Mockernut, making them harder to crack.
Many hickories produce sweet tasty nuts, while others can be very bitter (but all are still loved by wildlife).
All of these features of the fruits and their nuts can be used to help quickly identify the different types of hickory trees.
Identifying Hickory Trees by Branches and Tree Habit
Hickories all have various spreading branches. This is when there are typically ascending branches near the top of the tree, horizontal branches near the middle, and the lower branches descending.
Tree habit is the overall form a tree has when viewed from a distance. Since hickories have spreading branches, they typically have some form of open spreading crowns, which may be symmetrical or irregular.
Sometimes the spreading branches produce a rounded crown, and in species with shorter branches, it may become oval or oblong. This can vary within species and growing conditions.
Some hickories may have pyramidal crowns that can help to identify those species.
Since there is not much variability between species other than the same variability within species, branch growth, and tree habit are not often used to help identify the different types of hickory trees. However, when used in conjunction with other identification tools, it can be used to help differentiate the Carya genus as a whole from other deciduous trees with compound odd-pinnate leaves.
Identifying Hickory Trees by Bark
Hickory bark is often quite unique and varies between species, making it one final very useful tool in identifying the different types of hickory trees.
Hickory bark always starts out smooth when young, like most trees. Sometimes it remains smooth when mature.
Sometimes, however, it becomes variously grooved with longitudinal grooves that may be deep or shallow or intertwining and creating a diamond-like or V-shaped pattern.
Often the bark is exfoliating, sometimes in regular scaly rectangular plates, and sometimes these plates can be very large and broad and/or long. Sometimes these plates can be so long and large that they separate from the tree but still remain attached to it, producing a very unique and easily identifiable feature.
12 Different Types of Hickory Trees & Their Identifying Features (With Photos)
1. Pecan (Carya illinoinensis)
The Pecan tree is famous for its deliciously sweet and rich pecan nut used in pecan pies, pralines, and other sweet desserts.
Pecans are large trees that grow very tall and wide with very thick trunks.
They do best in full sun in deep, moist, average soil with good drainage.
They should be watered weekly to ensure good fruit production, especially if you live in a dry climate.
In humid climates, they can be prone to fungal pecan scab, but this is treatable.
You need more than one variety of pecan trees to produce fruit.
Pecans are monoecious, and their pollen is not released simultaneously as the flowers mature. So to ensure fruit production, a minimum of two different cultivars, or three as recommended by NC State Extension, is needed to guarantee cross-pollination occurs.
Identifying Features of the Pecan
Pecans are large trees with symmetrical, spreading crowns with numerous spreading branches.
Trunks are up to 6 ft wide, with light gray to brownish bark with scaly irregular to somewhat rectangular plates.
Compound leaves are 15 ½ – 27 ½” long with 9 – 13(7 – 17) leaflets. Petioles are hairless to scaly with scattered hairs.
Leaflets are ovate-lanceolate, often falcate, 0.8 – 6.3” long, 0.4 – 2.75” wide, with long-pointed tips, serrated margins, and terminals petiolules up to 1”. Lower surfaces are hirsute or with scattered hairs and scaly. Upper surfaces are hairless to rarely slightly hirsute and somewhat scaly in spring.
Male catkins are essentially sessile, up to 7” long.
Fruits are dark brown, ovoid, 1 – 2.4” long, and about half as wide with thin husks and winged sutures.
Nuts are tan to brown and black-mottled, smooth with thin shells and large, sweet seeds.
Often Confused With: The Pecan is often confused with Chinese Pistache (Pistacia chinensis) with superficially similar odd-pinnate leaves, but their leaflet margins are entire and have oblique bases, they don’t produce catkins, and their fruit is a drupe. It is also confused with Black Walnut (Juglans nigra), which has even more similar-looking leaves, but that one has deeply grooved bark, tufts of hairs in its leaf vein axils, and usually larger, rounded, warty fruits.
Other Common Names: Hardy Pecan
Native Area: Mostly in the Mississippi River valley and its tributaries from southern Iowa and east to Indiana, south to Alabama, Texas, and into northeastern Mexico
USDA Growing Zones: 5 – 9
Average Size at Maturity: 70 – 100 ft (to 144 ft) tall, 40 – 75 ft spread
Some Cultivars Available:
2. Mockernut Hickory (Carya alba, formerly Carya tomentosa)
Mockernut is still widely referred to as Carya tomentosa, but plant authorities now say it is Carya alba.
It is a long-lived tree reaching 500 years of age.
It is drought-tolerant once established, but when the temperature is quite high, it would still benefit from some watering.
While it will grow in partial shade, it prefers full sun.
It has a straight trunk making it valued for wood production.
It gets its common name comes from the struggle to crack its thick hard shell only to find a small but sweet nut inside.
It is the most common hickory in the USA, and its population is quite stable, except in eastern Kansas, where it is Imperiled at the western limit of its range.
Identifying Features of the Mockernut
Mockernut Hickoryies are tall trees with straight trunks and dark gray grooved bark.
Compound leaves are 12 – 20” long with 7(5) – 9 leaflets. Petiole and rachis are conspicuously hirsute and scaly.
Leaflets are ovate to elliptic or obovate, 1.6 – 7.5” long, 0.8 – 3.1” wide, terminal petiolule up to ½” long, with serrated margins and a usually acute or rarely long-pointed tip. Lower surfaces are hirsute with abundant scales, while upper surfaces are hirsute along the major veins and midrib and puberulent and scaly in spring.
Male catkins are up to 5.5” long, with hirsute and scaly stalks.
Fruits are reddish-brown, finely mottled, mostly rounded, 1.2 – 2” long, with husks to 0.8” thick dehiscing halfway or nearly to the base with smooth sutures.
Nuts are tan, mostly rounded, four-angled, and rugulose with thick hard shells and small sweet seeds.
Often Confused With: The Mockernut is often confused with Pignut Hickory, but that one has hairless to only somewhat pubescent petioles and rachis, longer terminal petiolules, lower leaf surfaces that are mostly hairless later in the season, and nuts that are not four-angled. It is also confused with Shagbark Hickory, but that one has characteristically shaggy bark that separates at the edges of its long plates, and it usually only has five and never more than seven leaflets with tufts of hairs in the axils near its serrations.
Other Common Names: Mockernut, White Hickory, Whiteheart Hickory, Hognut, Bullnut, Big Bud Hickory
Native Area: Eastern North America from southern Ontario, Canada, and northern Illinois, USA, east to Massachusetts and New York, south to eastern Texas, then east to northern Florida
USDA Growing Zones: 4 – 9
Average Size at Maturity: 50 – 60 ft (to 118 ft) tall, 30 – 40 ft spread
3. Black Hickory (Carya texana)
The Black Hickory is the most common hickory in Texas after the Pecan.
It grows well in dry, infertile soils and requires less watering than other hickories.
It is one of the most adaptable hickories, able to grow in a variety of environments, and it has a medium to fast growth rate when compared to other hickories.
Its height varies considerably with the environment. In dry upland areas, it may only grow to 30 ft tall but reach 134 ft in moist bottomlands.
It prefers partial shade.
Identifying Features of the Black Hickory
Black Hickory is a highly variable tree with dark gray to black deeply grooved bark.
Compound leaves are 7.9 – 19.7” long with 7 (5 – 9) leaflets on long petioles that are hairless to slightly hairy, often with conspicuous rusty brown scales.
Leaflets are ovate to obovate, elliptic, or linear-elliptic, 1.2 – 5.9” long, 0.4 – 3.1” wide, with serrated margins, long-pointed tips, and terminal petiolules to 0.4”. Lower surfaces are hirsute to hairless except hirsute along the midrib, with rusty brown scales. In spring, upper surfaces are scaly.
Male catkins are up to 6.3” long on rusty brown scaly stalks.
Fruits are bronze to reddish-brown, obovoid to rounded, 1.2 – 2” long, and about as wide, with thin husks to ⅛” and narrowly winged sutures.
Nuts are tan, obovoid, not angled or occasionally 2-4-angled, and rugulose with thick shells and sweet to bitter seeds.
Often Confused With: Black Hickory is often confused with Pecan, but that one has much lighter bark, more leaflets that are often falcate on a usually much longer compound leaf with terminal petiolules up to 1” long, plus more elliptical fruits with nuts that are typically mottled black and have sweet tasty seeds. It is also confused with Mockernut, which usually has acute leaflet tips, lower leaflet surfaces that are hirsute, shorter catkins on hirsute stalks, and much thicker husks surrounding a smaller nut.
Other Common Names: Buckley Hickory, Pignut Hickory
Native Area: Endemic to the southern USA in southeastern Kansas, Missouri, southwestern Indiana, Oklahoma, Arkansas, Mississippi, and eastern Texas
USDA Growing Zones: 5 – 9
Average Size at Maturity: 30 – 100 ft (to 134.1 ft) tall, 20 – 100 ft spread
4. Water Hickory (Carya aquatica)
Water Hickory gets its name from its ability to tolerate waterlogged soils.
In nature, it is often found in clay flats and backwater areas next to streams and rivers. There it is an important tree that helps clean floodwaters by slowing the flow rate and allowing sediments to settle.
However, it grows best in moist but well-drained loamy or silty soils.
It is a slow-growing tree that doesn’t fruit until it is about 20 years old.
It can reproduce aggressively by seed and regenerates from the stumps of cut trees.
Its nuts are bitter but loved by waterfowl.
Its population is considered secure, yet unassessed in much of its range and Critically Imperiled, Imperiled, or Vulnerable in four of the most northern states it has been assessed in.
Identifying Features of the Water Hickory
Water Hickory is a medium to tall hickory with a slender trunk, irregular narrow crown, and light gray to brownish bark exfoliating in long strips or broad plates, occasionally scaly plates.
Compound leaves are 15 – 24” long with 9 – 11(5 – 13) leaflets on villous petioles, becoming hairless with age.
Leaflets are ovate-lanceolate, often falcate, 0.8 – 7.5” long, 0.4 – 1.6” wide, with serrated or sometimes entire wavy margins, long-pointed tips, and terminal petiolules up to ½”. Lower surfaces are villous with hairy veins, densely scaly in spring. Upper surfaces are villous along the midrib near the base but hairless elsewhere.
Male catkins are up to 8.3” long on villous stalks.
Fruits are brown, bronze, or black, obovoid, 0.6 – 1.2” long with thin husks and winged sutures.
Nuts are chocolate brown, broadly obovoid, two-angled, and minutely bumpy with thin shells and bitter seeds.
Often Confused With: It is mostly only confused with Pecan, which has a thicker trunk, leaflets that are hirsute on the lower surface and hairless to rarely hirsute on the upper surface, male catkins that are sessile, and usually larger fruits with nuts that are smooth and not angled and contain much sweeter seeds.
Other Common Names: Bitter Pecan
Native Area: Endemic to the southeastern USA along the Atlantic and Gulf Coasts from Virginia south to Florida, west to Texas, plus all along the Mississippi River valley north to southern Illinois
USDA Growing Zones: 5 – 9
Average Size at Maturity: 60 – 100 ft (30 – 150 ft) tall, 25 – 60 ft spread
5. Shagbark Hickory (Carya ovata)
Shagbark Hickory is a popular tree often grown as an ornamental for its shaggy bark, abundant shade, and its occasional crop of tasty nuts.
It is a slow-growing tree with large nuts, but its production is unreliable from year to year, and the shells are thicker than pecan nuts, so they are not grown commercially.
It is a common native hickory in the eastern USA and southeastern Canada that can live more than 350 years.
They can tolerate various temperatures and climates but grow best in humid climates on moist, rich soils.
They grow in either full sun or partial shade.
Identifying Features of the Shagbark Hickory
Shagbark Hickory is a tall tree with light gray bark exfoliating in long strips or broad plates curling at their edges, creating a characteristic shaggy appearance.
Compound leaves are 11.8 – 23.6” long with 5(3 – 7) leaflets on hirsute to almost hairless petioles.
Leaflets are ovate, obovate, or elliptic, 1.6 – 10.2” long, 0.4 – 5.5” wide, with an acute to long-pointed tip, serrated margins, with sometimes much larger terminal leaflets on petiolules up to ⅔”. There are tufts of hairs in vein axils near serrations, and lower surfaces are usually hirsute and scaly.
Male catkins are up to 5.1” long on hairless stalks.
Fruits are brown to reddish-brown, more or less rounded, 1 – 1.6” long, with husks to 0.6” thick and smooth sutures.
Nuts are tan, ovoid, obovoid, or ellipsoid, four-angled, and rugulose with thick shells and sweet seeds.
Often Confused With: Shagbark Hickory is often confused with Bitternut Hickory, which has shorter compound leaves with more smaller leaflets and usually smaller fruits with nuts that are usually not angled. Pignut Hickory is also similar, but it usually has shorter and narrower leaflets that are hairless or pubescent but become hairless later in the season, plus male catkins on densely pubescent stalks and nuts that are not angled.
Other Common Names: Carolina Hickory, Scalybark Hickory, Upland Hickory, Shellbark Hickory
Native Area: Eastern North America from southern Ontario and Quebec, Canada south throughout the eastern USA from Minnesota southwest to eastern Texas and all states east excluding Florida and along the coast. Disjunct populations also occur in the mountains of northeastern Mexico.
USDA Growing Zones: 4 – 8
Average Size at Maturity: 70 – 90 ft (to 150 ft) tall, 50 – 70 ft spread
6. Southern Shagbark (Carya ovata var australis, formerly Carya carolinae-septentrionalis)
Southern Shagbark is often listed as Carya carolinae-septentrionalis, but plant authorities consider it to be a botanical variant of the Shagbark Hickory. People frequently confuse the two because of their similarities and because both grow in the southeastern USA.
It’s a beautiful tree with a large spreading canopy providing abundant shade, the characteristic shaggy bark of the type species, and the same delicious-tasting nuts.
Like the type species, however, the nuts are not reliable producers from year to year, so they are not used in commercial production.
They are a popular ornamental tree in gardens where they grow best in full sun in humid climates.
In nature, it grows on more basic (alkaline) soils higher in calcium than the slightly acidic soils that the type species likes to grow on.
Identifying Features of the Southern Shagbark Hickory
It is similar to Carya ovata with some minor differences in morphology and ecology, where it grows in calcium-rich basic soils instead of acidic soils.
It has more slender twigs at only about half as wide, only up to 0.12” thick, that start off green but turn reddish-brown to black instead of thicker and tan gray.
It also has buds that are smaller and black instead of more variable in color.
Its compound leaves are typically shorter, and its terminal leaflets are lanceolate to oblanceolate and differ more from the lateral leaflets.
The fruits and nuts are about ⅔ the size of the type species at ⅔ – 1” long.
The bark at the base of the tree is often tighter and less shaggy than that higher up the trunk.
While some argue it should be a distinct species, the differences are small and sometimes overlapping.
Often Confused With: See above on Shagbark versus Southern Shagbark Hickory.
Other Common Names: Carolina Shagbark Hickory, Carolina Hickory
Native Area: Endemic to southeastern USA from Kentucky east to Virginia, south to Mississippi, east to Georgia
USDA Growing Zones: 5 – 8
Average Size at Maturity: 50 – 65 ft (to 127 ft) tall, 20 – 40 ft (to 60 ft) spread
7. Pignut Hickory (Carya glabra)
Pignut Hickory is a slow-growing, long-lived tee with a straight trunk and a narrow crown made of slender, contorted branches.
It produces fruits that are usually bitter but can be variable and are loved by wild animals.
It grows in various sites in humid climates, from dry ridges and slopes to moist mountain soils.
It sprouts readily from stumps and roots but is difficult to propagate by cuttings.
It is usually a very healthy tree. The most common disease that can affect it is trunk rot caused by Poria spiculosa.
Identifying Features of the Pignut Hickory
Pignut Hickory has slender, contorted branches. Its light gray bark is smooth, grooved, or exfoliating in small plates or long strips.
Compound leaves are 7.9 – 23.6” long with 5 – 7(3 – 9) leaflets on hairless to somewhat pubescent scaly petioles.
Leaflets are ovate to elliptic or obovate, 1.6 – 8.3” long, 0.8 – 4” wide, with serrated margins, long-pointed, often narrowly so, terminal petiolules to 0.7”, hairless to densely pubescent and scaly lower surfaces that become hairless, and upper surfaces that are scaly in spring.
Male catkins are up to 5.1” long on hairless to densely pubescent stalks.
Fruits are tan to reddish-brown, obovoid, rounded or ellipsoid, not angled, 0.8 – 1.8” long and almost as wide, with husks to 0.2” thick dehiscing only partially with mostly smooth sutures.
Nuts are tan, obovoid to ellipsoid, not angled, and rugulose, with thick shells and bitter seeds.
Often Confused With: Pignut Hickory is often confused with Mockernut Hickory, but that one has characteristically large and almost rounded tomentose leaf buds, conspicuously hirsute and scaly petioles and rachis, hirsute lower leaflet surfaces, and more rounded fruits with thicker husks and rounded nuts that are four-angled. It is also confused with Bitternut Hickory, which has densely yellow-scaly terminal buds, often shorter compound leaves with more leaflets that are villous along the major veins on the lower surface and near the base on the upper surface with usually smaller fruits wider than they are long and nuts with thin shells and bitter seeds.
Other Common Names: Sweet Pignut, Coast Pignut Hickory, Smoothbark Hickory, Swamp Hickory, Broom Hickory
Native Area: Eastern North America from extreme southern Ontario south throughout the eastern USA from Missouri northeast to Michigan, south to eastern Texas, and all states east
USDA Growing Zones: 5 – 9
Average Size at Maturity: 50 – 65 ft (to 120 ft) tall, 30 – 40 ft spread
8. Red Hickory (Carya glabra var odorata, formerly Carya ovalis)
Red Hickory is often still referred to as its own species, Carya ovalis. Still, its morphological characteristics are similar enough to Pignut Hickory that Plant authorities list it as a botanical variant instead.
It’s a medium-sized tree with a more or less rounded crown with pretty gray, somewhat shaggy bark, sweet and tasty nuts, and dark, glossy green leaves that turn golden-yellow in the fall.
It is uncommon but widespread in eastern North America, growing further west than the Pignut Hickory typically does.
It is often found growing in dry, well-drained upland ridges and slopes.
It is a faster-growing hickory than some hickories.
Frequent hybridization with Pignut Hickory creates trees with intermediate characteristics that can be hard to differentiate.
Identifying Features of the Red Hickory
Red Hickory is a medium-sized tree with a straight trunk and a rounded to oval crown. Its light or dark gray bark often has interlacing grooves and ridges before eventually separating into fairly long, slightly shaggy plates.
Compound leaves usually have 7(5) leaflets on petioles and rachis that quickly become hairless.
Leaflets are also soon hairless other than scattered hairs on larger veins and in vein axils. The terminal leaflet is oblanceolate to narrowly obovate, while the lateral leaflets resemble the type species being ovate to elliptic or obovate.
Female flowers are in short red spikes at the ends of current-year branches.
Fruits are somewhat rounded, 0.8 – 1.8” long, with husks up to 0.2” thick, eventually splitting to the base.
Nuts are pale and four-angled above the middle with a sweet tasty seed.
Often Confused With: Red Hickory is mostly confused with Pignut Hickory, which has 5 – 9 leaflets with terminal leaflets that are larger but otherwise the same as their lateral leaflets, female flowers that are the usual green, fruits dehiscing only partially, and nuts that are not angled and have seeds that are usually bitter. Sometimes it is confused with Shagbark Hickory, but that one almost always has the characteristic shaggy long, plated bark that is lifted at the edges, and it also has tufts of hairs in the axils of its leaves near its serrations and lower surfaces that are usually hirsute.
Other Common Names: Sweet Pignut
Native Area: Southern Ontario, Canada, and in the United States, east to New Hampshire, south to northern Florida, west to eastern Texas, and north-west to Nebraska
USDA Growing Zones: 5 – 9
Average Size at Maturity: 50 – 80 ft tall, 45 – 60 ft spread
9. Bitternut Hickory (Carya cordiformis)
Bitternut Hickory is a large and relatively fast-growing hickory that is shorter-lived than most, living only to about 200 years.
It is sometimes grown as a shade tree, but not for its bitter fruits, though the wildlife does enjoy them.
It is often commercially harvested for its lumber.
It grows naturally in moist mountain valleys along streambanks and in swamps but can also be found on dry sites and in poor-quality soils.
However, it grows best in humusy, rich, medium to wet, well-drained soils in full sun to part shade.
It has no serious insect or disease problems.
Identifying Features of the Bitternut Hickory
Bitternut Hickories have pyramidal crowns and gray to brownish smooth, grooved, or plated scaly bark.
Leaves are 7.9 – 15.7” with 7 – 9(5 – 13) leaflets on mostly hairless petioles hirsute near the rachis.
Leaflets are ovate-lanceolate, rarely falcate, 1.2 – 7.5” long, 0.4 – 2.75” wide, with serrated margins, long-pointed tips, and terminal petiolules to ⅓”. Lower surfaces are villous along major veins, pubescent elsewhere, and very scaly in spring, remaining at margins till fall. Upper surfaces are villous on midribs near the base and sparsely scaly in spring.
Male catkins are up to 6.3” long on hairless to hirsute stalks
Fruits are brown, obovoid, or nearly rounded, 0.8 – 1.2” long, often slightly wider than long, with thin husks under ⅛” dehiscing halfway with winged sutures.
Nuts are light brown, ellipsoid to ovoid, not angled, and rugulose with thin shells and bitter seeds.
Often Confused With: Bitternut Hickory is often confused with Shagbark Hickory, but that one has longer compound leaves with few larger leaflets and usually larger fruits with four-angled nuts. Or with Pignut Hickory, which usually has longer leaves with fewer leaflets that are mostly hairless on their lower surfaces, and somewhat larger fruits, a bit narrower than they are wide, with slightly thicker husks and nuts with thicker shells.
Other Common Names: Bitternut, Swamp Hickory
Native Area: Eastern North America from Minnesota southwest to eastern Texas and all states east of that, plus southern Ontario and Quebec, Canada
USDA Growing Zones: 4 – 9
Average Size at Maturity: 50 – 80 ft (to 150 ft) tall, 30 – 50 ft spread
10. Shellbark Hickory (Carya lacinosa)
Shellbark Hickory is another one that is frequently grown in gardens and landscapes for its interesting bark and abundant shade.
It has the largest nuts of all the hickories, and they are sweet and edible but thick and hard to crack, so they’re rarely grown commercially.
In nature, it’s a bottomland species usually found on river terraces where it is subjected to brief seasonal flooding, but it will also grow in other sites.
It is a slow-growing, long-lived tree that grows best on deep, fertile, moist soils but does not do well in heavy clay.
It does well in full sun but is also more shade-tolerant than some of the other hickories.
It has no serious pests or diseases, but Pecan Weevils (Curculio caryae) and Hickory Shuckworms (Laspeyresia caryana) sometimes reduce seed production.
Identifying Features of the Shellbark Hickory
Shellbark Hickory has a slender trunk with light gray bark, usually exfoliating into large, broad plates that separate from the trunk, or sometimes grooved.
Compound leaves are 23.6 – 35.4” long with 7 – 9(5 – 11) leaflets on a finely hirsute petiole that’s hairless towards the base.
Leaflets are ovate to obovate or elliptic, 3.5 – 7.9” long, 1.2 – 3.9” wide, with coarsely serrated margins, narrowly long-pointed tips, and terminal petiolules to 0.6”. Lower surfaces are hirsute and scaly, and upper surfaces are puberulent throughout and hirsute along the midrib.
Male catkins are up to 7.9” with minutely hirsute and glandular-hairy stalks.
Fruits are large, 1.8 – 2.4” long, almost as wide, tan to brown, round to ellipsoid, with up to 0.5” thick, minutely hirsute husks and smooth sutures.
Nuts are tan, ellipsoid, four-angled, and rugulose with thick shells and sweet seeds.
Often Confused With: Shellbark has such large fruits that make it easy to identify. However, it is usually only confused with Shagbark Hickory, which usually has shorter compound leaves with never more than seven leaflets with often much larger terminal leaflets with tufts of hairs in the vein axils near the serrations, shorter male catkins on hairless stalks, and smaller fruits with slightly thicker husks.
Other Common Names: Kingnut, Bigleaf Shagbark Hickory, Big Shellbark, Bottom Shellbark, Thick Shellbark, Western Shellbark
Native Area: Eastern North America from Kansas and Oklahoma northeast to Michigan south to Arkansas and Tennesse with scattered disjunct populations throughout most of the rest of the eastern states excluding Louisiana, Florida, and northeast of New York
USDA Growing Zones: 5 – 9
Average Size at Maturity: 60 – 80 ft (to 121 ft) tall, 30 – 40 ft spread
11. Nutmeg Hickory (Carya myristiciformis)
Nutmeg Hickory is the rarest hickory in the USA, where it is found only in small, geographically isolated (disjunct) relic populations.
It grows on a variety of loamy, silty, or clayey soils that are moist but well-drained and nutrient-rich, often beside small streams or on nearby slopes or bluffs.
As a sapling, it can survive a long time in the shade, but as an adult tree, it requires much more sun.
It is relatively free of diseases and pests, other than bird peck defect caused by the yellow-bellied sapsucker. This causes defects in the wood but is relatively harmless to the tree itself.
Squirrels and other wildlife love the nuts.
While its population is listed Apparently Secure, it’s critically imperiled to vulnerable in six of the nine states it is found in.
Identifying Features of the Nutmeg Hickory
Nutmeg Hickories have narrow open crowns of stout, somewhat spreading branches with gray to brownish, grooved, or exfoliating bark separating into broad plates or long strips.
Compound leaves are 11.8 – 23.6” long with 7(5) – 9 leaflets on a densely scaly petiole.
Leaflets are ovate or obovate to elliptic, 1.2 – 6.7” long, 0.4 – 3.2” wide, with serrated margins, long-pointed tips, and short terminal petiolules under ⅛”. Lower surfaces are densely bronze scaly with hairs along the midrib in spring, while upper surfaces are pubescent along major veins in spring, with scattered scales.
Male catkins are up to 2.4” long on scaly stalks.
Fruits are light tan to bronze, obovoid to ellipsoid, about 1” long and about ⅔ as wide with thin husks and winged sutures.
Nuts are reddish-brown and mottled with tan, ellipsoid, not angled, and smooth with thick shells and sweet seeds.
Often Confused With: Because of its rarity, Nutmeg Hickory can easily be confused with more common species such as Black Hickory, which has dark bark that is deeply grooved, leaves with longer terminal petiolules up to 0.4”, and male catkins up to 6.3” long. Pecan often has longer leaves with usually many more leaflets and sessile male catkins up to 7” long. Shagbark Hickory has its characteristic shaggy bark, usually five leaflets with tufts of hairs in vein axils near serrations, and male catkins up to 5.1” long.
Other Common Names: Swamp Hickory, Bitter Water Hickory
Native Area: Disjunct populations most abundant in Arkansas and Selma, Alabama but found from Texas east to Mississippi, north into Oklahoma and Arkansas, with even more disjunct populations found from Georgia to North Carolina and in northeastern Mexico
USDA Growing Zones: 8 – 11
Average Size at Maturity: 50 – 115 ft tall, 30 – 50 ft spread
12. Scrub Hickory (Carya floridana)
Scrub Hickory is a narrow endemic species with the narrowest range of any hickory, being found only in central Florida.
While it can grow to large tree sizes when the conditions are right, it often remains as a 10 – 15 ft tall multi-stemmed shrub, giving it its common name of Scrub Hickory.
It is usually shrubby because it’s mostly confined to the scrub vegetation ecosystems of coastal dunes and dry sandy ridges in its range.
In shrub form, it can bare fruit on stems 3 – 4 ft tall, and its seeds are sweet and tasty.
Its population is considered Apparently Secure though officially, it has been assigned no status rank yet in the state of Florida.
Identifying Features of the Scrub Hickory
Scrub Hickory is a multi-stemmed shrub or occasionally a medium-sized tree. Its gray bark is smooth or grooved.
Compound leaves are 7.8 – 11.8” long, with 3 – 7 leaflets. Petioles have coarse hairs and scales in the spring, becoming hairless.
Leaflets are ovate to elliptic or obovate, 1.6 – 3.9” long, 0.8 – 1.6” wide, with coarsely serrated margins and long-pointed tips. Terminal petiolules are absent or short. Lower surfaces have rusty brown scales and hairs only in leaf axils. Upper surfaces have scales in the spring.
Male catkins are up to 2.4” long on coarsely hairy stalks with rusty brown scales.
Fruits are bronze to dark brown, obovoid to oblong, not angled, 1.2 – 1.6” long, about ⅔ as wide, with husks less than ⅛” thick with slightly winged sutures.
Nuts are tan, ellipsoid, not angled, and rugulose, with thick shells and sweet seeds.
Often Confused With: Scrub Hickory is sometimes confused with Pignut Hickory which is always a tree that has usually much longer leaves with usually more leaflets, longer catkins up to 5.1” long, and wider fruits with slightly thicker husks.
Other Common Names: Florida Hickory, Florida Scrub Hickory
Native Area: Narrow endemic of Central Florida
USDA Growing Zones: 10
Average Size at Maturity: 10 – 15 ft (to 82 ft) tall, 8 – 12 ft (to 50 ft) spread
Growing Hickory Trees in Your Garden
Hickory trees are tall, handsome trees that provide abundant shade in the summer.
Depending on the species and how many you grow, they also provide bountiful harvests of tasty nuts loved by wildlife and humans alike.
If you decide to grow a hickory tree, like all trees, it is important that you do some research so that your tree enjoys a long and healthy life in your yard.
First, be sure you know the USDA Planting Zone that you live in.
Next, check your chosen tree’s soil, light, and moisture requirements and compare that to the spot you want to plant it in your yard. Check out How to Pick A Tree For Your Yard for more information on choosing the right tree for the right spot in your yard.
Most hickories grow well in USDA zones 5 – 8, though some will grow well down to zone 4 and others up to zone 11. Unfortunately, none will do well below zone 4. If you live in zone 3 or below, you should choose a tree more suitable for colder climates. Certain species of aspen or poplars work well if you want deciduous trees or spruce if you are interested in coniferous trees.
Hickories generally prefer growing in full sun, but many also do well in partial shade, and some are even shade tolerant.
Hickories generally do best in fertile soils, so be sure to add a good amendment of compost or well-rotted manure to your soil when planting your tree. Then, give it an annual top-dressing of organic matter after the soil warms in the spring.
They generally grow best on neutral or slightly alkaline soils, though some do well in slightly acidic soils as well.
Most hickories do require a moderate amount of water. While getting established, their soil should remain moist (not wet) for about a year. After that, if you live in a humid climate, your tree should be fine but water it during extreme droughts.
If you live in a dry climate, then you will need to water more frequently or choose something like Black Hickory that is better adapted to drier climates.
Some hickories do well in wetter soils, so if your land is wet, then Water Hickory is a great choice.
All hickories are monecious and self-incompatible. This means that if you wish to harvest the nuts, you will need to grow a minimum of two (three is best) different cultivars to ensure that you get good cross-pollination and, therefore, fruit production.
Hickory trees grow best by planting seeds or by transplanting young trees when still a sapling. They all have large taproots, so they do not take to transplanting well.
Like the related walnuts, hickory species also secrete an allelopathic chemical known as juglone that prevents the growth of sensitive plants, so keep that in mind when choosing a spot for your tree or companion plants around your tree.
Hickories are relatively pest and disease free compared to some trees. But they are host to more than 130 different species of fungi, including leaf diseases, wood rot, root rot, and stem canker.
Prune any diseased, damaged, or dead limbs as you notice them. If you don’t want to hinder fruit production, never prune more than 25% of the branches in a single year.
Always try to choose species native to your area to enhance biodiversity and wildlife values; the wildlife around you will thank you for it!
Fortunately, hickories are slow-growing trees with little invasive potential and are not found on any invasive species lists worldwide at this time, so they are fairly safe to plant outside their native range.
Handsome Hickory Trees
The pollen of Carya species is known to be a severe allergen to many of those with seasonal allergies.
The tallest hickory in the world may be a Red Hickory in eastern Kentucky that is 160 ft tall.
Hickory wood is very strong and dense and is used in making furniture and wood flooring, as well as tool handles and sometimes musical instruments. It is also popular as a flavoring wood for smoking meats. Long ago, it was used to make gunstocks, ramrods, and other tools back in the frontier days of America.
The Cherokee often used Mockernut wood to make tools and arrows. They used the inner bark for baskets, clothing, and tea to treat colds and other illnesses. Native tribes throughout eastern North America harvested the bountiful nuts of all the tasty species and used them as an important nutritious food source.
Pecan trees are a more recently domesticated crop in human history, only beginning in the late 1800s, but have become a major crop thanks to the delicious nuts they produce.
Pecans, and other Carya species, produce delicious edible nuts often used in pecan pies, pralines, cookies, cakes, desserts, and ice creams.
Pecans are also used to make pecan oil and pecan butter.
The seeds of all species, whether sweet or bitter, are loved by wildlife, including squirrels, chipmunks, bears, ducks, quail, wild turkeys, deer, foxes, raccoons, and mice. They are a nutrient-dense food source critical to the health and survival of many species.
Birds and squirrels also feed on the male catkins in the spring.
Deer occasionally browse on the leaves and twigs.
Numerous Lepidoptera (moths and butterflies) species feed on the hickory trees, with as many as 200 different native species in North America using them as a primary or additional food source.
Now you know all about the handsome hickory trees, how to identify them, and how they benefit the wildlife around you.
You can go out and identify the ones growing around you, and just maybe, plant one in your own yard so you, the wildlife, and future generations can enjoy it for years to come!
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