Corylus avellana
| Hazelnut (Corylus avellana) | |
|---|---|
| |
| Scientific name | Corylus avellana |
| Genus | Corylus |
| Family | Betulaceae |
| Order | Fagales |
| Native range | Europe to the Caucasus[1] |
| Growth habit | Deciduous, suckering shrub or small tree[2] |
| Pollination | Wind-pollinated; compatible trees required[3] |
| Fruit | Edible hazelnuts in leafy husks; late summer to fall[4] |
Corylus avellana, commonly called hazelnut, common hazel, European filbert, or cobnut, is a deciduous European-to-Caucasian shrub or small tree grown for its edible nuts.[1] It is monoecious, but pollen compatibility between trees matters: a single tree cannot reliably pollinate itself, and pollen shed must overlap the receptive period of a compatible partner.[3]
Description[edit | edit source]
The plant commonly forms several stems and produces suckers, so an established specimen can become a broad shrub or thicket if those shoots are left in place.[5] Leaves are deciduous. The conspicuous male catkins and much smaller female flowers appear in the late-winter to early-spring period before or around leaf emergence; nuts develop inside leafy husks.[4]
The species is accepted as Corylus avellana. Corylus sylvestris is a listed synonym, not an alternative page title.[1]
Cultivation[edit | edit source]
Soil and water[edit | edit source]
Full sun and good drainage are practical starting points for a planting. Avoid a persistently saturated site, particularly where the shrub's expanding sucker system would be difficult to manage. The plant's natural multi-stemmed habit makes space for sucker removal or renewal stems more useful than a tightly confined planting plan.[4][5]
Sun and humidity[edit | edit source]
Place hazelnut in an open, sunny position when nut production is the goal; the species is listed for full-sun culture and is also used as a large landscape shrub.[4] Good air movement around a multi-stemmed plant is a sensible orchard-design consideration, but disease response remains dependent on cultivar, site, season, and local pathogen pressure.
Seasonal changes[edit | edit source]
This is a temperate deciduous plant. Catkins and female flowers are visible in late winter or early spring, while nuts are released from their leafy husks in late summer or fall.[4] In cultivation, plan pollinizer placement and winter-to-spring flowering overlap before leaf-out, then keep the ground accessible for late-season nut collection.
Propagation[edit | edit source]
Seedlings are variable and do not preserve a named cultivar. Seed dormancy can be managed with stratification, but the treatment depends on the nut's condition: the examined germination study found two months of cold stratification best for seeds without pericarp, while intact nuts responded best to two months warm followed by two months cold treatment. Immediate autumn sowing produced the best spring emergence in that study.[8] Those results are treatment-specific rather than a universal schedule.
Layering, stool-bed layering, tissue culture, and grafting onto selected rootstocks are documented clonal or nursery routes.[3][5] Layering is useful when preserving a selected plant is more important than producing variable seedlings. Rootstock choice changes establishment and management: the reviewed literature describes C. colurna seedlings and clonal rootstocks including 'Dundee' and 'Newberg', while also noting differences in transplanting, sucker production, and site performance.[5]
A public discussion of propagating the ornamental C. avellana 'Contorta' in a zone-6 container describes mixed participant advice rather than a verified trial, so it should be treated only as a lead for local experimentation, not as a general propagation protocol.[3]
Flowering, fruiting, and harvest[edit | edit source]
Corylus avellana bears separate male and female flowers on the same plant. It is wind-pollinated and sporophytically self-incompatible; plant compatible trees whose pollen shed and female receptivity overlap. Cultivar identity and flowering timing therefore matter when choosing a pollinizer.[3] A laboratory study of pollen from a wild accession and three commercial cultivars found that 15% sucrose in 1% gelatin performed best in its hanging-drop germination assay; that result describes an in-vitro test, not an orchard pollination recipe.[6]
Nuts mature inside leafy husks and are released in late summer or fall.[4] Harvest timing and yield vary with cultivar, site, season, and orchard management. In southwestern British Columbia orchards without fungicides, a four-to-six-year field study recorded cultivar-specific flowering, eastern filbert blight symptoms, and yields rather than one result that applies to every planting.[7]
Fruit and uses[edit | edit source]
The edible nut is the principal reason to grow this species. The kernel is enclosed by a leafy husk until maturity, and the species is the principal European hazelnut crop in commercial cultivation.[3][4] The horticultural description here does not extend into health claims or a safety rating.
Cultivars and selections[edit | edit source]
Cultivar choice should be tied to local flowering, disease, and yield conditions rather than to a universal ranking. In a four-to-six-year study at five southwestern British Columbia sites adjacent to eastern-filbert-blight-infected orchards, Eta, Gamma, Theta, and Yamhill showed no symptoms in the reported observations, Jefferson showed negligible symptoms, and Sacajawea showed substantial symptoms. The same study recorded site- and age-specific yield differences, including a reported maximum of 9.3 kg per tree for fifth-leaf Jefferson; these results are regional observations, not guarantees of resistance or yield elsewhere.[7]
Most European cultivars are vulnerable to eastern filbert blight in parts of eastern North America, where pathogen diversity and local pressure complicate selection.[3] Choose named material with compatible pollination timing and locally relevant disease information, and keep ornamental names such as 'Contorta' separate from nut-production recommendations.
Photos[edit | edit source]
References[edit | edit source]
- ↑ [6] The Development of an Improved Medium for the In Vitro Germination of Corylus avellana L. Pollen.
- ↑ [7] Flowering and yield of eastern filbert blight resistant hazelnut cultivars in southwestern British Columbia.
- ↑ [8] Effects of seed moisture content, stratification and sowing date on the germination of Corylus avellana seeds.
Image credits[edit | edit source]
- Corylus avellana 0008.JPG — H. Zell, “Corylus avellana nuts,” Wikimedia Commons, CC BY-SA 3.0. Individual file page.
- Corylus avellana Italy Moggio Udinese 2008 1004.JPG — Joadl, “Corylus avellana shrubs in northern Italy,” Wikimedia Commons, CC BY-SA 3.0-at. Individual file page.
