Shrub · Betulaceae
Hazelnut
Corylus avellana
Give it full sun, a compatible partner, and room to spread, and the hazel rewards you with nuts each fall.
Full sun
Every 7–14 days
USDA 4–8
12–20 ft · 3.7–6.1 m
Overview
The hazelnut is a hardy, multi-stemmed shrub from the birch family, native across Europe and into western Asia. It goes by many names, from cobnut to filbert, and earns its keep two ways: a steady crop of edible nuts in autumn and a handsome, suckering habit that suits a hedge or orchard edge. Hardy from zone 4 to 8, it shrugs off cold winters that finish off less rugged trees.
Flowering happens long before the leaves, when pale yellow catkins dangle through the bare branches of late winter. Pollen travels on the wind, not by bees, which is why a lone bush rarely fills out a crop. Most hazels are largely self-incompatible, so you need a second, compatible cultivar nearby for the female flowers to set nuts.
Grown well, a hazel is a long-lived, low-fuss plant. The two things that shape your success are choosing blight-resistant cultivars and staying ahead of the suckers, which throw up new shoots from the base and roots all season. Keep those in check and the shrub holds a clean form for decades.
Care
The short version: plant in full sun and deep, well-drained soil, set a compatible pollinizer nearby, water through the first few years and dry spells, and prune in late winter while cutting out suckers and any blight.
Light
Hazelnut crops best in full sun, which ripens more wood and fills out more nuts. It will take partial shade and still grow, but expect a lighter harvest in shadier ground.
Water
Water regularly through the first two or three years while the roots reach down, and again during dry spells while the nuts are sizing. An established shrub handles drought fairly well, though even moisture always gives you a better crop. Let the top half of the soil dry between waterings.
Soil
Plant in deep, well-drained loam with plenty of organic matter, though hazel tolerates a wide range of ground, even shallow rocky sites. Aim for a pH between 6.0 and 7.5, from slightly acidic to slightly alkaline.
Temperature
This is a tough, cold-hardy shrub that takes winter lows near -31°F (-35°C) and summer heat up to about 95°F (35°C). The real weak point is a hard freeze during the late-winter bloom, which can cost you that year's nuts.
Humidity
Ordinary outdoor air suits it, somewhere around 40% to 70%, so there's no number to chase. Good airflow through the canopy matters more, since open growth keeps fungal trouble down.
Feeding
Feed in early spring before bud break, working off a soil or leaf test rather than guesswork. A nitrogen-rich balanced fertilizer, applied seasonally, keeps growth and nut fill on track.
Pruning
Prune in late winter while dormant, taking out dead, weak, and crossing wood and thinning to keep an open center. Cut any blight cankers well below the visible stromata, and remove the basal suckers regularly to hold a clean tree form.
Repotting
Hazelnut is a long-lived landscape and orchard shrub grown in the ground, not in pots, so it's rarely repotted. If you do start one in a container, move it on before the roots circle, stall the shoots, or send water straight through the mix.
Size & spacing
A mature hazel stands 12 to 20 feet (3.7 to 6 m) tall and spreads 8 to 15 feet (2.4 to 4.5 m) wide. Give it that much room from its neighbors so air moves freely and the suckers have somewhere to be cut back.
When to plant
Hazelnut runs on the dormant season. Set new plants out from late fall to early spring while they sleep, watch the wind-pollinated catkins open in late winter, and gather the nuts as they ripen and drop from late summer into early fall.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Late fall to early spring while dormant
- Harvest: Wind-pollinated catkins open late winter to early spring; nuts ripen and drop late summer to early fall
Hardiness
USDA hardiness zones: 4–8
Temperature: down to -34°C
Troubleshooting
Most hazelnut trouble shows up in the wood, the crop, or the crowd of shoots at the base. Learn to read those signs and you can step in before a small problem spreads. Match what you see below, then act while it still helps.
Dying branches with rows of raised black bumps on the bark
This is eastern filbert blight, a fungus that erupts as football-shaped rows of black stromata along the bark and slowly girdles the wood. Cut infected limbs at least 2 to 3 feet below the lowest visible canker and burn or bin the wood. Plant resistant cultivars and clear out any wild hazels nearby that keep feeding the disease.
Fix:
- Prune out infected limbs at least 2 to 3 ft below the lowest visible canker and destroy the wood
- Apply protectant fungicides during the spring bud-break infection period
- Replace highly susceptible plantings with resistant cultivars
Plenty of catkins but few nuts, or shells that come up empty
Hazelnut is wind-pollinated and largely self-incompatible, so a lone bush often shows a heavy catkin display and still sets almost no nuts. A hard freeze during the late-winter bloom can wipe out the catkins or female flowers too. Plant at least one cultivar that sheds compatible pollen and overlaps the bloom, and site plants where late frosts bite less.
Fix:
- Plant at least one cultivar that sheds compatible pollen and overlaps bloom with the main variety
- Site plants where late frosts are less severe
A thicket of shoots rising from the base and roots
Corylus avellana suckers freely from the base and along its roots, and left alone those shoots build into a dense thicket. Cut or pull the suckers while they are still young, several times across the growing season. Mowing or cultivating around the drip line severs the spreading shoots before they take hold.
Fix:
- Cut or pull suckers while young, several times per growing season
- Mow or cultivate around the drip line to sever spreading shoots
Toxicity
Good news for a household with pets and children: the hazelnut is not poisonous. No part of the plant is listed as toxic, and the ripe kernels are a familiar food. The only real cares are the choking hazard of whole nuts and the upset that their heavy fat can cause a dog.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Nothing on the hazelnut is poisonous to cats, so a curious nibble of leaf or shell won't harm them.
Dogs None
The plant itself is safe for dogs. The catch is the nuts, since a whole one can choke a small dog and the high fat load can upset the stomach or, in large amounts, stir up pancreatitis.
Horses Safe
Hazelnut foliage and nuts pose no poisoning risk to horses.
Rabbits Safe
The leaves and twigs aren't toxic to rabbits, though the rich, fatty nuts don't suit their diet and are best kept away.
Livestock Safe
Cattle, goats, and sheep can graze around hazelnut without any toxic effect.
Birds Safe
No part of the plant harms birds, and many wild ones happily crack open the ripe nuts.
People Safe
The ripe kernels are a familiar food and safe to eat, raw or roasted, apart from anyone with a tree-nut allergy.
Whole nuts are a choking and gastrointestinal obstruction hazard and are high in fat, so large quantities can cause stomach upset and, in dogs, raise the risk of pancreatitis.
Varieties
Most named hazels are bred for blight resistance, kernel quality, or looks. These are the ones worth knowing by name.
Jefferson
A blight-resistant OSU release planted widely for its large, high-quality kernels.
Yamhill
A compact, early-maturing OSU cultivar that carries strong resistance to eastern filbert blight.
Barcelona
A traditional Oregon commercial cultivar that is highly susceptible to eastern filbert blight.
Contorta
The ornamental Harry Lauder's Walking Stick, grown for its twisted, corkscrew stems and winter interest.
Companions
Plant near
Compatible pollinizer hazelnut cultivar: Supplies overlapping, cross-compatible pollen needed for nut set
Clover or other legume ground cover: Living mulch that fixes nitrogen and suppresses weeds in the orchard floor
Keep apart
Wild or abandoned hazel (Corylus) plants: Act as a reservoir of eastern filbert blight inoculum that infects nearby plantings
How to propagate
Hazelnut takes well to several methods, from coaxing roots on a low branch to lifting the suckers it offers up on its own. The choice depends on whether you want an exact copy of a cultivar or are happy with a seedling.
LayeringModerate
Late winter to early spring · 1 to 2 years to rooted, separable plants
Mound and simple layering are the standard ways to clone a cultivar on its own roots. Pin or mound soil over low shoots in late winter to early spring, and they grow their own roots over the next 1 to 2 years before you cut them free as new plants.
DivisionEasy
Dormant season, late fall to early spring · 1 season
The simplest route is to use the suckers the shrub throws anyway. Lift rooted basal suckers from an established clump during the dormant season, from late fall to early spring, and replant them, and they settle in within a single season.
GraftingDemanding
Late winter on dormant rootstock · 1 to 2 years
Grafting puts a named cultivar onto a selected rootstock and takes a steady hand. Work in late winter on dormant rootstock, and the union needs 1 to 2 years to grow into a reliable, productive plant.
SeedModerate
Sow outdoors in fall or stratify cold and moist for 2 to 3 months · Several years to bearing
Seed is easy enough but won't reproduce the parent, since seedlings don't come true to cultivar. Sow outdoors in fall or give the seed 2 to 3 months of cold, moist stratification first, then expect several years of growth before the plant starts bearing nuts.
Myths
A single hazelnut bush will reliably crop on its own.
Corylus avellana is wind-pollinated and largely self-incompatible, so one bush usually sets little or no fruit by itself. It needs a separate compatible pollinizer cultivar nearby for a real crop of nuts.
Hazelnut plants are poisonous to cats and dogs.
The plant isn't on the ASPCA toxic list and the foliage and nuts won't poison pets. The real risks are choking on a whole nut and stomach upset from the high fat, not poisoning.