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// SPECIES PROFILE · TREE · NATIVE · CROSS TIMBERS

Black Hickory

Carya texana

The Cross Timbers hickory — a small, slow-growing, deeply taprooted upland tree that takes the place of pignut and shagbark on the dry sandstone ridges and chert breaks of NE Oklahoma. Black hickory grows shoulder-to-shoulder with post oak and blackjack oak in the classic post oak–blackjack–black hickory association that defines the Cross Timbers, and is one of the most reliable hard-mast trees on sites too dry and rocky for any other hickory species.

// QUICK FACTS
Family
Juglandaceae (walnut family)
Group
Tree (pecan/hickory subgenus)
Native range
S Cent. US: OK, AR, MO, TX, LA, KS, IN/IL fringe
USDA hardiness
Zones 6–9 (Tulsa = 7a/7b)
Mature size
40–60 ft · trunk 12–20 in DBH
Lifespan
150–300 yrs (slow grower)
Sun
Full sun to part shade
Soil
Dry, rocky, acidic sandstone & chert; tolerates poor soils
Water
Strongly drought-hardy; deep taproot
Bloom
Catkins April–May (wind-pollinated, monoecious)
Nuts ripen
Sept–Oct, drop with husk
Wildlife value
Hard mast for squirrel, turkey, deer; lepidoptera host
Lepidoptera hosts
~200 spp on Carya (regal moth, luna, hickory horndevil)
Ecological role
Cross Timbers upland hard-mast tree
Black Hickory (Carya texana) — compound leaves and characteristic dark furrowed bark
Carya texana — the upland hickory of the Cross Timbers. Photo via Wikipedia / Wikimedia Commons.

Identification

[ field key — bark · leaves · nuts · lookalikes ]

Habit & Bark

A small to medium deciduous tree, typically 40–60 ft tall in NE Oklahoma with a narrow, irregular crown and a single straight bole. On the toughest sandstone ridges of the Cross Timbers it often tops out at only 25–35 ft and looks almost shrubby. Bark is the strongest field mark: dark gray to nearly black, deeply furrowed into narrow, hard, blocky ridges — conspicuously darker and more rugged than the lighter, shaggier or platy bark of mockernut, pignut, and shagbark. Twigs are slender, reddish-brown, often with rusty hairs when young; terminal buds are small (5–8 mm), brown, and covered with persistent rusty pubescence — a useful winter ID character.

Leaves

Pinnately compound, alternate, 8–12 in long with typically 7 leaflets (occasionally 5), the terminal three larger than the basal pair. Leaflets are lanceolate, finely serrate, dark glossy green above and paler beneath with characteristic rusty-brown stellate hairs along the midrib and lower veins (use a hand lens). Petioles and rachises are also rusty-pubescent when young. Fall color is a clean butter-yellow — brief but striking against the rust-orange post oaks.

Flowers & Nuts

Monoecious — male catkins (3–4 in, drooping in threes) and inconspicuous female flower spikes appear together with new leaves in April–May. Wind pollinated. The nut is spherical to slightly pear-shaped, 1–1.5 in across, enclosed in a thin (2–3 mm) brown husk that splits along four sutures at maturity. The shell is hard, the kernel small but sweet and edible. Crops are good every 2–3 years, with heavy mast years driving visible spikes in fox squirrel and wild turkey numbers across the Cross Timbers.

Lookalikes

Most often confused with Carya glabra (pignut hickory) and C. tomentosa (mockernut). Black hickory is distinguished by its dark, narrowly-furrowed bark, persistent rusty pubescence on bud scales and leaf undersides, and its preference for dry sandstone uplands where pignut and mockernut are less common. C. ovata (shagbark) is immediately separable by its peeling, plate-like bark. Young black hickory can be confused with C. cordiformis (bitternut), but bitternut has bright sulphur-yellow naked buds and prefers moist bottomland sites.

Habitat & Range in NE Oklahoma

Black hickory is a near-endemic of the south-central US and reaches the very heart of its range across NE Oklahoma. It is the defining hickory of the Cross Timbers, the broad band of post oak–blackjack savanna that runs from the Arbuckles north through the Tulsa region and on into the Osage and the Flint Hills foothills. Look for it on the sandstone ridges of Osage, Pawnee, Creek, Tulsa, Wagoner, and Mayes counties, on the chert breaks of the western Ozarks (Adair, Cherokee, Delaware), and on dry rocky uplands throughout the Ouachita foothills. It is largely absent from the wet bottomlands of the Arkansas, Verdigris, and Neosho rivers, where it is replaced by water hickory, bitternut, and pecan.

Soil preference is the giveaway: black hickory thrives on dry, acidic, often extremely shallow sandstone- or chert-derived soils where deeper-rooted, faster-growing mesic hickories cannot establish. Its early energy investment goes almost entirely into a massive taproot — a 2-year-old seedling may have a 4–6 ft taproot above only a few inches of shoot. That root architecture is what allows it to coexist with post oak and blackjack on sites that bake to over 110°F in summer and crack open in drought.

Historically, the Cross Timbers burned every 2–7 years from lightning and Indigenous (Osage, Quapaw, Caddo) burning, maintaining an open oak-hickory savanna with widely spaced large trees and a tallgrass understory. Black hickory tolerates these surface fires better than its competitors thanks to its thick bark and ability to resprout from the root collar. Modern fire suppression has thickened the canopy and increased cedar encroachment, but the post oak–black hickory ridge-tops remain the most recognizable signature of the Tulsa-region landscape.

Ecology & Wildlife Value

[ hard mast · lepidoptera · cavities · soil ]

Hard mast for wildlife

Hickory nuts are the second most important hard mast in the Cross Timbers after acorns. Eastern fox squirrels, gray squirrels, wild turkey, white-tailed deer, raccoon, and black bear (returning to E Oklahoma) all feed heavily on black hickory nuts in the fall. The hard, thick shell means relatively few species can crack them; fox squirrels are the dominant disperser, caching nuts singly in soil up to 50 m from the parent tree — the same scatter-hoarding behavior that regenerates oak-hickory forests across the eastern US.

Lepidoptera larval host

The genus Carya hosts ~200 species of Lepidoptera in North America — a top-five host plant by caterpillar diversity, comparable to oak and willow. Notable specialists on hickory in NE Oklahoma include the spectacular regal moth (Citheronia regalis) whose 6-inch "hickory horned devil" caterpillars feed exclusively on hickory and walnut foliage, the luna moth (Actias luna), the walnut sphinx, and various underwing moths (Catocala) including C. epione and C. piatrix.

Cavities & structure

Mature black hickory snags develop heart rot relatively late but, once established, provide long-lived cavities used by pileated woodpeckers, red-headed woodpeckers, screech owls, fox squirrels, and southern flying squirrels. The hard, deeply furrowed bark also harbors invertebrates fed on by nuthatches, brown creeper, and bark-foraging warblers in winter. Old Cross Timbers black hickories may carry half a dozen active cavities each.

Soil & mycorrhizae

Black hickory forms ectomycorrhizal associations with a wide range of fungi, including several Russula, Cortinarius, and Lactarius species shared with oaks — one mechanism by which trees in the post oak–black hickory association may share belowground resources. Decomposing leaves are calcium-rich and slowly improve the very thin upland soils where the tree grows, building a fragile but functional A horizon over centuries.

A tree that resists transplanting: Black hickory's massive juvenile taproot makes it nearly impossible to dig and move — even small wild seedlings usually die when transplanted. The reliable establishment method is direct seeding of fresh nuts in fall, planted 1–2 in deep where the tree is to grow permanently. Container stock is rarely sold; if you find it, choose the youngest, smallest available and plant immediately.
Slow grower — plan generationally: Black hickory adds only 6–12 in of height per year on dry sites and may take 25–40 years to produce its first reliable nut crop. This is a tree to plant for grandchildren, not for yourself. The flip side: a black hickory you direct-seed today can easily live 200+ years and be visited by ten generations of squirrels.

Horticulture & Care

[ direct seed · siting · minimal care · long horizon ]

When to plant intentionally

Black hickory is the right choice for: restoring Cross Timbers savanna on dry rocky upland sites, wildlife mast plantings on properties with squirrel, turkey, or deer management goals, and shelterbelts and naturalistic landscapes on sites too poor for any other hickory. It is the wrong choice for small urban lots, formal landscapes, irrigated lawns, or anywhere a fast-growing shade tree is needed.

Establishment by direct seeding

Maintenance

Effectively none, once established. Do not fertilize — rich soil promotes weak, fast growth that breaks easily in ice storms. Remove competing vegetation in the immediate root zone for the first three years. Black hickory does not need pruning; its naturally upright form develops without intervention. Avoid mechanical damage to the trunk — like all hickories it does not compartmentalize bark wounds well.

Pests & diseases

Cultivars & selections

Black hickory has no named horticultural cultivars — it is a wild-only species not in commercial trade. Use locally collected seed from healthy mature trees in your county or an immediately adjacent county. The Oklahoma Forestry Services seedling program and the Kerr Center for Sustainable Agriculture (Poteau, OK) occasionally distribute Cross Timbers native tree seedlings; Bois d'Arc Creek and Sandhills nurseries sometimes stock small B&B specimens. For commercial nut production, black hickory is dramatically outperformed by improved pecan cultivars (pecan) — black hickory's value is ecological, not horticultural.

Cultural & Material Uses

Black hickory has a smaller but parallel record to its better-known eastern hickory cousins — the same tough, shock-resistant wood and edible nuts, on a tree that just happens to grow where almost nothing else in the genus will.

Sources & Further Reading

  • USDA NRCS PLANTS Database — Carya texana: plants.usda.gov/plant-profile/CATE6
  • USDA Forest Service Silvics of North America, Vol. 2 (Hardwoods) — Smith, H.C., chapter on Carya texana: srs.fs.usda.gov — carya/texana
  • USDA Forest Service Fire Effects Information System (FEIS) — Carya texana: fs.usda.gov/database/feis — cartex
  • Lady Bird Johnson Wildflower Center — Carya texana: wildflower.org — CATE6
  • Missouri Botanical Garden Plant Finder — Carya texana.
  • Stahle, D.W. et al. — The Ancient Cross Timbers Consortium, University of Arkansas: dendrochronology and old-growth status of post oak–black hickory ridges in OK and TX.
  • Hoagland, B.W. (2000), "The vegetation of Oklahoma: A classification for landscape mapping and conservation planning," Southwestern Naturalist 45(4):385–420 — ecoregional classification of Cross Timbers.
  • Oklahoma Biological Survey — Atlas of the Vascular Plants of Oklahoma, distribution maps for Carya texana.
  • OSU Extension — Cross Timbers and Prairies of Oklahoma series (NREM publications).
  • Wikipedia — Carya texana: en.wikipedia.org/wiki/Carya_texana (CC BY-SA 4.0; portions of the description summarize Wikipedia content).
  • Wasowski, S. & A. (1988), Native Texas Plants — field descriptions for the Texas-Oklahoma Cross Timbers flora.

Companion Planting

[ guild · polyculture · cross-layer pairings ]

In a Cross Timbers oak-hickory savanna, black hickory pairs naturally with: chickasaw plum (Prunus angustifolia), american persimmon (Diospyros virginiana), fragrant sumac (Rhus aromatica), blackjack oak (Quercus marilandica), smooth sumac (Rhus glabra), and bur oak (Quercus macrocarpa).

black hickory works best as a canopy or sub-canopy partner above the herbaceous and shrub layers.