Editing Corylus americana

{| class="wikitable" style="float: right; width: 320px; margin-left: 1.25em; margin-bottom: 1em;"
! colspan="2" style="background: #e8e8e8;" | American hazelnut (''Corylus americana'')
|-
| colspan="2" style="text-align: center;" | [[File:Corylus_americana_kz2.jpg|300px|Corylus americana in the Missouri Botanical Garden, St. Louis]]
|-
! Scientific name
| ''Corylus americana''
|-
! Common names
| American hazelnut; American filbert
|-
! Genus
| [[Corylus]]
|-
! Family
| [[Betulaceae]]
|-
! Order
| [[Fagales]]
|-
! Habit
| Deciduous, suckering shrub
|-
! Native range
| Eastern and central North America
|-
! Fruit
| Small edible nut in a husk
|}

''Corylus americana'' is a deciduous North American hazel commonly called American hazelnut or American filbert. It forms a many-stemmed shrub and can spread by suckers and rhizomes, making it useful as a thicket-forming nut plant but requiring space or periodic renewal pruning in a managed planting.<sup id="cite_ref-1">[[#cite_note-1|[1]]]</sup> The accepted name is ''Corylus americana''; seed-grown plants should not be assumed to match a named selection in vigor, kernel quality, or bearing.<sup id="cite_ref-2">[[#cite_note-2|[2]]]</sup>

== Description ==

American hazelnut is usually a low to medium-sized, many-stemmed shrub. Accounts describe plants from about 1–3 m in natural settings and cultivated shrubs that can reach roughly 3–5 m, with size influenced by site and management.<sup id="cite_ref-3">[[#cite_note-3|[3]]]</sup> Woody rhizomes commonly occur several inches below the soil surface and produce shoots some distance from the parent; the shallow root system is concentrated in the upper soil layer.<sup id="cite_ref-4">[[#cite_note-4|[4]]]</sup> This combination gives established plants resilience and regenerative capacity, but it can also make an old clump difficult to confine.

The plant is monoecious: male catkins and female flowers occur on the same shrub. Pollination is by wind, and compatible pollen from more than one plant is needed for dependable nut production because hazelnuts are self-incompatible.<sup id="cite_ref-5">[[#cite_note-5|[5]]]</sup>

== Cultivation ==

=== Soil and water ===

In its native habitats, American hazelnut occurs in rocky woodlands, hillsides, pastures, and thickets. Rich, moist, well-drained soil supports stronger growth than either droughted ground or stagnant wet soil.<sup>[[#cite_note-4|[4]]]</sup> A site with organic matter and reliable summer moisture is a useful starting point, but drainage remains important around the crown and rhizomes. In an orchard-style planting, allow enough room for suckers and for access during harvest; remove unwanted shoots rather than repeatedly disturbing the main root system.

=== Sun and humidity ===

The species tolerates shade in natural woodland settings, while full sun generally improves nut production.<sup>[[#cite_note-2|[2]]]</sup> Open exposure also makes flowering, pollination, pruning, and harvest easier to monitor. In hot climates, maintain root-zone moisture and airflow rather than assuming that woodland shade alone will preserve nut yield. The native shrub is adapted to seasonal outdoor humidity, not to a permanently saturated crown.

=== Seasonal changes ===

American hazelnut is deciduous. Catkins develop in late winter or early spring, followed by nut development through summer and ripening from late summer into fall.<sup>[[#cite_note-3|[3]]]</sup> Keep young plants watered while shoots and nuts are developing; after leaf fall, reduce irrigation where rainfall is adequate but do not leave a newly planted root system dry. Renewal pruning can be done throughout the year in mild conditions, with heavier old-growth removal spread over time so that a clump retains productive stems.<sup>[[#cite_note-2|[2]]]</sup>

== Propagation ==

Seed-grown plants preserve useful genetic variation but may differ substantially in vigor, yield, kernel quality, and disease response. That variability is important when choosing plants for a small orchard: use more than one compatible plant and keep provenance records rather than treating one seedling as representative of the species.<sup id="cite_ref-8">[[#cite_note-8|[8]]]</sup>

Corylus seed has a dormant embryo. The USDA seed-manual guidance describes removal of the pericarp followed by about two months of prechilling at 3–5 °C for germination testing; this is a genus-level starting point, not a guaranteed ''C. americana'' schedule, so seed lots should be kept separate and monitored for delayed emergence.<sup id="cite_ref-6">[[#cite_note-6|[6]]]</sup> Protect a seedbed from rodents and drying while stratified seed is handled.

Layering and other vegetative methods can preserve a selected plant more faithfully than seed. Rhizomatous shoots may also establish new plants, but a sucker's identity and root connection should be confirmed before it is distributed as a named selection. Rutgers guidance describes layering and tissue-culture propagation in hazelnut production, while the forest monograph documents the species' natural vegetative spread by rhizomes.<sup>[[#cite_note-5|[5]]]</sup><sup>[[#cite_note-4|[4]]]</sup>

== Flowering, fruiting, and harvest ==

Male catkins release pollen in early spring, while the small female flowers receive wind-borne pollen. Because pollen compatibility and flowering overlap matter, plant at least two genetically distinct, compatible plants; a single shrub may flower abundantly and still set few nuts.<sup id="cite_ref-7">[[#cite_note-7|[7]]]</sup> Seedling plantings are especially variable, so a group of plants is more dependable than a single specimen.

The nuts occur in clusters, are enclosed in husks, and are commonly about 12 mm (roughly one-half inch) long. Ripening extends from late summer into fall, with the exact harvest window varying by plant and climate.<sup>[[#cite_note-3|[3]]]</sup><sup>[[#cite_note-2|[2]]]</sup> Harvest promptly as husks mature and dry the nuts before storage. A Wisconsin grower described picking while husks still remained on the nuts, then drying them in paper grocery bags to reduce squirrel losses; this is a location-specific practical observation, not a universal harvest rule.<sup id="cite_ref-10">[[#cite_note-10|[10]]]</sup>

Nut production begins earlier on some managed plants than on others. Extension guidance gives approximate early-bearing ranges for hazelnuts but warns that seed-grown production varies widely; use those ranges for planning rather than as a promise for every American hazelnut.<sup>[[#cite_note-7|[7]]]</sup> An attributed report from a mixed American-hazelnut seedling patch described large clusters with smaller kernels and less-favored flavor, while one presumed pure American plant in open exposure was described as bearing well with good flavor. Species purity and provenance were partly uncertain in that report.<sup id="cite_ref-11">[[#cite_note-11|[11]]]</sup>

== Fruit and uses ==

The small nuts are edible when mature and can be eaten fresh or dried for later use. Kernel size and flavor vary among wild plants and seedlings, so select fruiting plants by tasting their own crop rather than relying on the species name alone. Extension orchard guidance covers drying and storage of hazelnuts; nuts intended for storage should be fully dry and protected from heat, insects, rodents, and squirrel access.<sup>[[#cite_note-7|[7]]]</sup>

== Pests and diseases ==

Japanese beetles, scale insects, leafhoppers, and caterpillars may damage foliage. Leaf spots, blight, and crown gall are reported problems, and deer may browse the plant; salt exposure is poorly tolerated.<sup>[[#cite_note-2|[2]]]</sup> American hazelnut is also used in eastern hazelnut breeding because tested material has shown substantial tolerance to eastern filbert blight, but breeding evaluations do not establish identical resistance in every wild plant or seedling.<sup id="cite_ref-9">[[#cite_note-9|[9]]]</sup>

== Cultivars and selections ==

The documented selection ''Rush'' was selected from a local wild population for high yield and unusually large nuts and was later used in breeding. It may interest growers seeking a more deliberately selected American-hazelnut source, but the selection record does not make those traits universal, and it should not be confused with ordinary seedlings or interspecific hybrids.<sup>[[#cite_note-3|[3]]]</sup> Other names recorded in botanical and nursery histories include ''Little Filly'', ''Littlepage'', ''Purpleleaf Bailey Select'', ''Sun Harvest'', and ''Winkler''; comparable fruit, bearing, pollination, and climate data are insufficient for a performance table.<sup>[[#cite_note-3|[3]]]</sup>

== Photos ==

[[File:Corylus_americana_5497076.jpg|300px|Corylus americana fruits in Bayfield County, Wisconsin]]

== References ==

* <span id="cite_note-1"></span>[[#cite_ref-1|↑]] '''[1]''' [https://api.gbif.org/v1/species/match?name=Corylus%20americana GBIF species match: Corylus americana].

* <span id="cite_note-2"></span>[[#cite_ref-2|↑]] '''[2]''' [https://plants.ces.ncsu.edu/plants/corylus-americana/ North Carolina Extension: Corylus americana].

* <span id="cite_note-3"></span>[[#cite_ref-3|↑]] '''[3]''' [https://www.treesandshrubsonline.org/articles/corylus/corylus-americana/ Trees and Shrubs Online: Corylus americana].

* <span id="cite_note-4"></span>[[#cite_ref-4|↑]] '''[4]''' [https://www.fs.usda.gov/database/feis/plants/shrub/corame/all.html USDA Forest Service Fire Effects Information System: Corylus americana].

* <span id="cite_note-5"></span>[[#cite_ref-5|↑]] '''[5]''' [https://njaes.rutgers.edu/e368/ Rutgers Cooperative Extension, ''Choosing Plants for a Hazelnut Orchard in New Jersey'' (Bulletin E368)].

* <span id="cite_note-6"></span>[[#cite_ref-6|↑]] '''[6]''' [https://www.fs.usda.gov/nsl/Wpsm/Corylus.pdf USDA Forest Service, ''Corylus L. Woody Plant Seed Manual'' entry].

* <span id="cite_note-7"></span>[[#cite_ref-7|↑]] '''[7]''' [https://extension.usu.edu/yardandgarden/research/hazelnuts-in-the-home-orchard Utah State University Extension, ''Hazelnuts in the Home Orchard''].

* <span id="cite_note-8"></span>[[#cite_ref-8|↑]] '''[8]''' [https://doi.org/10.1007/s11295-020-01462-y Revord, Lovell, Brown, Capik & Molnar (2020), ''Using genotyping-by-sequencing derived SNPs to examine the genetic structure and identify a core set of Corylus americana germplasm'']. ''Tree Genetics & Genomes'' 16:65. DOI: 10.1007/s11295-020-01462-y.

* <span id="cite_note-9"></span>[[#cite_ref-9|↑]] '''[9]''' [https://rucore.libraries.rutgers.edu/rutgers-lib/72613/ Teckam (2024), ''Phenology, chilling requirements, and disease resistance in hybrid hazelnut'']. Rutgers University dissertation record and abstract.

* <span id="cite_note-10"></span>[[#cite_ref-10|↑]] '''[10]''' [https://growingfruit.org/t/hazelnuts-for-zone-5b/2933 ''Hazelnuts - FOR Zone 5b''], GrowingFruit.org firsthand grower discussion.

* <span id="cite_note-11"></span>[[#cite_ref-11|↑]] '''[11]''' [https://growingfruit.org/t/hazelnuts-2023/50364?page=3 ''Hazelnuts 2023''], GrowingFruit.org firsthand grower discussion, page 3.

== Image credits ==

* ''Corylus americana kz2.jpg'': Krzysztof Ziarnek, Kenraiz, [https://commons.wikimedia.org/wiki/File:Corylus_americana_kz2.jpg Wikimedia Commons file page], CC BY-SA 4.0. Used in the summary table; caption identifies the Missouri Botanical Garden subject.

* ''Corylus americana 5497076.jpg'': Steven Katovich, USDA Forest Service, Bugwood.org, [https://commons.wikimedia.org/wiki/File:Corylus_americana_5497076.jpg Wikimedia Commons file page], CC BY-SA 3.0 Unported. Used in Photos as a documented fruit view from Bayfield County, Wisconsin.