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// SPECIES PROFILE · SHRUB · NATIVE · EDIBLE NUT

American Hazelnut

Corylus americana

The eastern North American native filbert — a multi-stemmed, suckering shrub of woodland edges, savannas, and hedgerows whose yellow-tan male catkins dangle conspicuously from leafless February branches and whose small, sweet, fully edible nuts ripen in late summer inside fringed leafy bracts. Corylus americana reaches the western edge of its range in eastern Oklahoma, growing wild on the margins of the Ozark plateau and persisting in old fence rows from Tulsa eastward. It is one of the most rewarding edible native shrubs for a NE Oklahoma food-forest hedgerow.

// QUICK FACTS
Family
Betulaceae (birch family)
Group
Deciduous shrub — multi-stemmed, root-suckering
Native range
SE Canada south to Georgia, west to E. Oklahoma, E. Kansas, & Saskatchewan
USDA hardiness
Zones 4–9 (Tulsa = 7a/7b)
Mature size
8–16 ft tall × 8–16 ft wide; thicket-forming
Sun
Full sun for best nut crop · tolerates part shade
Soil
Adaptable — rich loam to rocky chert; pH 5.5–7.5
Water
Medium — drought-tolerant once established
Sex / pollination
Monoecious, wind-pollinated; self-incompatible — plant 2+ unrelated genotypes
Catkin shed
February – early March in NE OK
Female bloom
February — tiny crimson stigmas on bud tips
Nut ripe
Late August – September
Wildlife value
Catkins for early bees · nuts for squirrels, jays, turkey, deer · thicket cover
Ecological role
Edible nut shrub · earliest spring catkins · hedgerow staple
American Hazelnut (Corylus americana) showing nuts inside fringed leafy involucre
Corylus americana — nuts ripening inside the characteristic fringed leafy involucre. Photo via Wikipedia / Wikimedia Commons.

Identification

[ field key — suckering thicket · doubly toothed leaf · long catkin · fringed husk ]

Habit & bark

Multi-stemmed deciduous shrub, typically 8–12 ft in NE Oklahoma, occasionally to 16 ft, with multiple slender upright-arching stems rising from a clonal root system. Forms slowly expanding thickets by root-suckering — a single plant may eventually occupy a 15–20 ft patch. Bark is smooth, light grayish-brown, with conspicuous horizontal lenticels; young twigs are densely covered with stiff red glandular hairs that are diagnostic to the touch.

Foliage

Leaves alternate, simple, broadly oval to obovate, 3–6 in long, with a heart-shaped or rounded base, abruptly pointed tip, and doubly serrate (sharply toothed) margins. Upper surface medium green, slightly rough; underside paler with conspicuous parallel veins and downy hairs along the veins. Fall color is a clean warm yellow to coppery-orange — one of the better native shrub fall displays in our region.

Flowers & nuts

Hazelnut is monoecious — both sexes on one plant — but functionally self-incompatible, requiring a second unrelated plant for nut set. Male flowers are 2–3 in pendant tan-yellow catkins that form in autumn, persist through winter naked on the bare twigs, and shed pollen in February. Female flowers are tiny: a cluster of brilliant crimson-red stigmas emerging from a swollen bud tip, only a few mm across — easy to miss but well worth a February hand-lens visit. Nuts ripen August–September enclosed in a distinctive fringed, leafy double-bract involucre that distinguishes C. americana from the related beaked hazel (C. cornuta) of further north.

Confusables

Vegetatively similar to witch-hazel (Hamamelis virginiana) and young alders (Alnus serrulata) before flowering or fruiting. The doubly-serrate leaf with cordate base and the bristly red-glandular young twigs are the most reliable vegetative cues. The European hazel (C. avellana) and Turkish hazel (C. colurna) used in landscape and orchard plantings have larger nuts and lack the fringed involucre — their husks are tubular or open-cupped.

Habitat & Range in NE Oklahoma

Corylus americana reaches the southwestern edge of its native range in eastern Oklahoma. It occurs naturally on woodland edges, savanna transitions, fence rows, and stream-terrace bottomlands in the eastern Cross Timbers and the Oklahoma Ozarks — Cherokee, Adair, Delaware, Mayes, and Wagoner counties hold the bulk of documented records. It is a classic component of the historical "savanna ecotone" that ringed pre-settlement tallgrass prairie: half-shade, periodic light fire, deep loam soils.

Hazelnut's near-disappearance across much of the central US is a textbook fire and edge-habitat story — with prairie fires suppressed and most hedgerows gone, the species has retreated to remnant sites and to intentional plantings. It re-sprouts vigorously after top-kill by fire and was historically held in check at modest size by the same fire regime that maintained tallgrass prairie. In NE Oklahoma it tolerates the full local range of upland soils provided drainage is reasonable, and is increasingly used in conservation hedgerows, riparian buffers, and small-scale food-forest plantings around Tulsa and northeastward.

Ecology & Wildlife Value

[ wind pollination · early pollen · mast crop · lepidoptera · cover ]

Pollination & early pollen

Wind-pollinated — the dangling tan catkins shed enormous quantities of February pollen that drifts on the slightest breeze. While not insect-pollinated, the catkins are a meaningful early-spring resource for honey bees and emerging native bees gathering protein-rich pollen on warm winter days when little else is available. The combination of earliest catkin-shed and the species' wind-pollination biology makes hazelnut a winter phenology marker.

Wildlife & mast

The nuts are a major hard-mast crop for gray and fox squirrels, blue jays, woodpeckers, wild turkey, ruffed grouse (further north), white-tailed deer, raccoons, and small rodents. Wildlife typically harvests the entire crop within days of ripening — if you want nuts, you will be racing the squirrels. Twigs and buds are browsed in winter by deer and rabbits.

Lepidoptera

Larval host for an estimated 100+ moth and butterfly species in the eastern US (Tallamy data), including polyphemus moth, io moth, walnut sphinx, several underwings, and the white admiral / red-spotted purple butterflies. This high herbivore-support value places hazelnut near the top of native shrubs for songbird food-web function.

Cover & structure

Multi-stemmed thicket habit provides excellent nesting cover for cardinal, brown thrasher, gray catbird, indigo bunting, and a wide range of woodland-edge sparrows. The dense suckering root system is a useful tool for stabilizing erosion-prone banks and re-establishing structural shrub-zone understory in degraded woodland edges.

Eastern filbert blight (EFB): The fungal disease Anisogramma anomala is endemic on wild Corylus americana across most of the eastern US — native plants are largely tolerant, but spores from C. americana can devastate plantings of the European hazel C. avellana (the commercial filbert). If you grow European hazel for nuts in NE Oklahoma, do not intermix with native C. americana; choose EFB-resistant cultivars (Rutgers / Oregon State breeding program: 'Jefferson', 'Yamhill', 'Wepster', etc.) or plant the modern American × European hybrids.
The Upper Midwest hybrid hazel program: The Upper Midwest Hazelnut Development Initiative (UMN Extension, Univ. of Wisconsin, the Arbor Day Foundation, and Badgersett Research) has released a series of selected C. americana × C. avellana hybrids that combine American hardiness and EFB tolerance with European nut size. These are the most promising native-leaning nut crop for NE Oklahoma small-orchard plantings as of the mid-2020s.

Horticulture & Care

[ siting · pollination groups · pruning · pests · harvest · cultivars ]

When to plant

Bare-root plants in late winter (February) before bud break; container plants in early fall (October) for best establishment before next summer's heat. Avoid mid-summer planting.

Planting & establishment

Pruning & training

Two basic approaches: thicket form (do almost nothing — remove the oldest 1/3 of stems every 4–5 years) for wildlife and mixed uses, or nut-orchard form (limit to 4–6 main stems, renew the oldest yearly, suppress suckers with mowing) for maximum harvest and access. Nuts are borne on previous year's wood; prune in late winter (January–February) before catkins shed.

Pests & diseases

Harvest

Pick whole nut clusters when the involucre fades from green to yellowish-tan but before the husks open and the nuts drop — otherwise wildlife will beat you to them. Cure in a single layer in a dry shaded shed for 2–3 weeks; husks will dry and release the nut. Cured in-shell nuts store 6–12 months in a cool dry pantry.

Cultivars & selections for NE Oklahoma

Selection Type Distinguishing feature Notes for Tulsa
Wild seed-grown Pure C. americana Small sweet nuts, full ecological value Best for hedgerow and ecological plantings; modest individual yields.
'Winkler' Selected C. americana Improved nut size; reliable cropper in zone 7 One of few named American-type selections; works well in NE OK.
'Rush' Selected C. americana Hardy, vigorous, modest nut size Old reliable selection; good thicket-former.
Badgersett hybrid hazels C. americana × avellana Larger nuts, EFB tolerance, vigorous The most promising current direction for NE OK nut production.
'Jefferson', 'Yamhill', 'Wepster' OSU EFB-resistant C. avellana Commercial European nut size, EFB-resistant Marginal in our summers; need irrigation and protection from heat.
C. avellana 'Contorta' (Harry Lauder's Walking Stick) European ornamental Twisted, contorted branches Strictly ornamental — not for nuts.

Cultural & Material Uses

Corylus americana has the longest documented Indigenous food-use record of any native nut shrub of the eastern US, and as both food and craft material it remains among the most versatile native plants available to a NE Oklahoma grower.

Sources & Further Reading

  • USDA NRCS PLANTS Database — Corylus americana: plants.usda.gov/plant-profile/COAM3
  • USDA Forest Service Fire Effects Information System (FEIS) — Corylus americana: fs.usda.gov/database/feis/plants/shrub/coramy
  • USDA NRCS Plant Guide — Corylus americana: hedgerow and conservation use.
  • Lady Bird Johnson Wildflower Center — Native Plant Database, Corylus americana: wildflower.org — COAM3
  • Missouri Botanical Garden Plant Finder — Corylus americana culture and cultivar notes.
  • University of Minnesota Extension — Hybrid Hazelnut Production in the Upper Midwest; Upper Midwest Hazelnut Development Initiative (UMHDI) publications.
  • Oregon State University — OSU Hazelnut Breeding Program publications on EFB-resistant cultivars (Mehlenbacher, S.A. et al.).
  • OSU Extension (Oklahoma State University) — tree-nut culture for Oklahoma (HLA series).
  • Tallamy, D.W. & Shropshire, K.J. (2009), Conservation Biology — ranking of native woody plants by lepidoptera support.
  • Moerman, D.E. (1998). Native American Ethnobotany. Timber Press — documented Indigenous uses of Corylus species.
  • Wikipedia — Corylus americana: en.wikipedia.org/wiki/Corylus_americana (CC BY-SA 4.0; portions of description and ecology summaries draw on Wikipedia content).

Companion Planting

[ guild · polyculture · cross-layer pairings ]

In a hedgerow or thicket, american hazelnut pairs naturally with: downy hawthorn (Crataegus mollis), crossvine (Bignonia capreolata), aromatic aster (Symphyotrichum oblongifolium), inland sea oats (Chasmanthium latifolium), cosmos (Cosmos bipinnatus), and american beautyberry (Callicarpa americana).

Site american hazelnut on the woodland edge or in the mid-layer of a guild beneath taller canopy trees.