Hazelnut (Barcelona)
Corylus avellana 'Barcelona'
The most widely planted hazelnut variety in North America, Barcelona produces large, flavorful nuts with excellent kernel quality. This reliable producer is known for its consistent heavy yields and good cold hardiness, making it an ideal choice for home orchardists. The nuts have a rich, buttery flavor perfect for eating fresh or using in baking.
Harvest
120-150d
Days to harvest
Sun
Full sun to partial shade
Zones
4–8
USDA hardiness
Height
12-20 feet
Planting Timeline
Showing dates for Hazelnut (Barcelona) in USDA Zone 7
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Hazelnut (Barcelona) · Zones 4–8
Growing Details
Zone-by-Zone Planting Calendar
Complete Growing Guide
Barcelona hazelnuts require cross-pollination from a compatible variety like Jefferson or Ennis to set fruit reliably, so plant at least two cultivars together rather than a single tree. This variety prefers well-draining soil and full sun exposure, needing at least six hours of direct light daily to maximize nut production. Barcelona is notably susceptible to Eastern filbert blight, a fungal disease prevalent in humid climates, so ensure excellent air circulation through proper pruning and avoid overhead watering that creates leaf wetness. The trees typically begin producing nuts by year three or four, with peak yields arriving by year six. A practical tip: thin developing clusters to one nut per husk in early summer to increase individual nut size and quality rather than allowing the tree to bear excessive small nuts that waste energy.
Light: Full sun (6 or more hours of direct sunlight a day), Partial Shade (Direct sunlight only part of the day, 2-6 hours). Soil: High Organic Matter, Loam (Silt), Shallow Rocky. Soil pH: Alkaline (>8.0), Neutral (6.0-8.0). Drainage: Good Drainage, Moist. Height: 12 ft. 0 in. - 20 ft. 0 in.. Spread: 8 ft. 0 in. - 15 ft. 0 in.. Spacing: 6-feet-12 feet. Maintenance: Low. Propagation: Layering, Root Cutting, Seed. Regions: Coastal, Mountains, Piedmont.
Harvesting
Barcelona hazelnuts reach peak harvest readiness when the husks transition from green to brown and begin splitting naturally along the seams, revealing the hard-shelled nut within. The nuts themselves should feel firm and weighty when gently squeezed, indicating full kernel development. Rather than a single harvest event, Barcelona typically follows a continuous dropping pattern throughout late August through September, so plan multiple collection passes across several weeks to gather nuts at optimal ripeness. A helpful timing tip: begin harvesting when the first nuts drop naturally to the ground rather than waiting for the entire crop to mature simultaneously, as early-falling nuts often indicate peak kernel quality and oil content, making them ideal for fresh consumption or immediate processing.
The fruit, in the form of a nut, is enclosed by a short leafy involucre, or husk. They appear in clusters of 1 to 5 and are released from the husk in late summer when the nut has ripened. The rounded nuts are about 1" in diameter.
Color: Brown/Copper, Gold/Yellow. Type: Nut. Length: 1-3 inches. Width: 1-3 inches.
Garden value: Edible, Showy
Harvest time: Fall, Summer
Edibility: Hazelnuts (cobnuts) are edible, and this plant is used in the production of these nuts.
Storage & Preservation
Store freshly harvested Barcelona hazelnuts in a cool, dry location at 32–50°F with 50–65% humidity to maintain kernel quality and prevent rancidity. Keep them in breathable mesh bags or shallow containers that allow air circulation. Under these conditions, in-shell hazelnuts remain fresh for 3–4 months; shelled kernels last 4–6 weeks before developing off-flavors.
For longer preservation, freezing is highly effective: shell and store kernels in airtight containers or vacuum-sealed bags at 0°F or below for up to two years with minimal quality loss. Roasting before freezing intensifies the buttery flavor. Drying is another reliable option—spread shelled kernels in a dehydrator at 130–150°F for 8–10 hours until brittle, then store in airtight jars. Barcelona's higher oil content makes it particularly suited to hazelnut butter production; roast and process dried kernels within a few months of harvest for the richest flavor and creamiest texture.
History & Origin
Barcelona hazelnut originated in Spain, where it was selected from local hazelnut populations cultivated for centuries in the Mediterranean region. The variety became commercially significant in the early twentieth century as Spanish growers recognized its superior nut size, flavor, and productivity compared to other European cultivars. Barcelona was subsequently introduced to North America in the mid-1900s, where it quickly became the dominant commercial variety due to its adaptability to diverse climates and reliable cropping. While detailed documentation of its original breeder remains limited, Barcelona's prominence in international hazelnut commerce solidified it as the standard against which other varieties are measured.
Origin: Europe and Western Asia
Advantages
- +Most widely planted hazelnut variety in North America with proven reliability
- +Produces large nuts with excellent kernel quality and rich, buttery flavor
- +Consistent heavy yields make it ideal for home orchardists and small farms
- +Good cold hardiness allows successful growing in northern climates
- +Versatile nuts perfect for fresh eating, baking, and culinary applications
Considerations
- -Highly susceptible to Eastern Filbert Blight, a serious fungal disease threat
- -Vulnerable to multiple pests including filbert aphid, mites, and filbert weevil
- -Requires cross-pollination with compatible hazelnut variety for optimal nut production
- -Moderate growing difficulty demands regular pest and disease management attention
Companion Plants
Comfrey is the workhorse here — its deep taproots pull up calcium and potassium and deposit them on the surface when leaves die back, which matters directly for nut fill and shell development. Clover planted under the canopy fixes nitrogen at the root level and keeps bare soil from compacting between Barcelona's widely spaced trunks. Chives, wild garlic, and yarrow pull in beneficial insects that prey on Myzocallis coryli before colonies get ahead of you. Black walnut is a hard no — juglone toxicity is well-documented in Corylus, and at 15-20 feet spacing between your hazelnuts, you have no margin to absorb a toxic neighbor.
Plant Together
Comfrey
Deep roots bring nutrients to surface, leaves make excellent mulch and fertilizer
Clover
Fixes nitrogen in soil, provides ground cover and attracts beneficial insects
Chives
Repels aphids and other pests while attracting beneficial pollinators
Lavender
Deters pests like moths and beetles, attracts pollinators, and tolerates similar soil conditions
Marigolds
Repel nematodes and aphids, attract beneficial insects for pest control
Nasturtiums
Act as trap crop for aphids and cucumber beetles, edible flowers attract pollinators
Wild Garlic
Natural fungicide properties help prevent fungal diseases, repels various pests
Yarrow
Attracts beneficial insects, improves soil health, and may enhance disease resistance
Keep Apart
Black Walnut
Produces juglone which is toxic to hazelnuts and inhibits their growth
Fennel
Allelopathic properties inhibit growth of nearby plants including nut trees
Pine Trees
Acidify soil significantly which hazelnuts cannot tolerate, compete for nutrients
Nutrition Facts
Per 100g serving. % Daily Value based on 2,000 calorie diet. Source: USDA FoodData Central (FDC #2515375)
Pests & Disease Resistance
Resistance
Susceptible to Eastern Filbert Blight in some regions
Common Pests
Filbert aphid, mites, filbert weevil
Diseases
Eastern Filbert Blight, bacterial blight
Troubleshooting Hazelnut (Barcelona)
What you'll see, why it happens, and what to do about it.
Sunken, dark cankers spreading along branches, often with cracked bark and dieback starting mid-canopy
Likely Causes
- Eastern Filbert Blight (Anisogramma anomala) — a fungal canker disease; spores spread by rain splash in spring
- Susceptible cultivar — Barcelona is notably vulnerable to this pathogen
What to Do
- 1.Prune out all cankered wood at least 12 inches below the visible margin and burn or bag the cuttings — don't compost them
- 2.Apply copper-based fungicide in early spring before bud break, and again at 10-14 day intervals through bloom
- 3.Consider interplanting with a blight-resistant pollinator like 'Jefferson' or 'Theta' to reduce disease pressure over time
Leaves curling and showing sticky residue (honeydew), sometimes with a black sooty coating on upper surfaces
Likely Causes
- Filbert aphid (Myzocallis coryli) — colonies build fast on new growth in warm weather
- Sooty mold fungus colonizing the aphid honeydew as a secondary problem
What to Do
- 1.Knock aphids off with a firm stream of water from a hose — effective if you catch them early before populations explode
- 2.Spray insecticidal soap directly on colonies, covering leaf undersides; repeat every 5-7 days for 2-3 applications
- 3.Encourage or introduce lacewings and ladybugs, which are effective predators of Myzocallis coryli
Harvested nuts are hollow, shriveled, or have a small round exit hole in the shell
Likely Causes
- Filbert weevil (Curculio occidentis) — larvae feed inside developing nuts before dropping to soil to pupate
- Filbert worm (Cydia latiferreana) — a separate moth larva that also bores into nut kernels
What to Do
- 1.Collect and destroy any nuts that drop early — larvae are still inside and will overwinter in the soil if left
- 2.Rake and disturb the soil under the canopy in late fall to expose pupae to birds and freezing temps
- 3.For persistent pressure, apply beneficial nematodes (Steinernema carpocapsae) to moist soil under the drip line in early spring
Frequently Asked Questions
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Growing Guides from Wind River Greens
Where to Buy Seeds
Sources & References
External authority sources used in compiling this guide.
See the Methodology page for how this data is sourced, what's AI-assisted, and known limitations.