Shrub · Betulaceae
Hazelnut
Corylus avellana
Give it full sun, a pollen partner, and room to spread, and the hazel earns its place with a harvest 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, at home across Europe and into western Asia, and a quietly versatile presence in a garden. Cobnut or filbert by other names, it earns its keep two ways, with a dependable autumn harvest of edible nuts and a soft, suckering form that suits a boundary hedge or the loose edge of an orchard. Hardy from zone 4 to 8, it holds its own where the winters bite hardest.
Its calendar has a charm all its own, since the flowers arrive well before the leaves, when pale yellow catkins hang from bare branches to mark the turn of late winter. The wind carries the pollen, not the bees, which is the reason a lone bush rarely fills a crop. Most hazels are largely self-incompatible, so a second, compatible cultivar set nearby is what lets the season come good.
As a fixture in the wider landscape, a hazel rewards a little forethought about placement and upkeep. Two choices shape how gracefully it lives with a space: reaching for blight-resistant cultivars and keeping ahead of the suckers that rise from the base and roots through the season. Manage both and the shrub holds a clean, composed outline for decades.
Care
The short version: give it full sun and deep, well-drained soil, place a compatible pollinizer nearby, water through the first few years and dry spells, and prune in late winter while clearing the suckers and any blight.
Light
A hazel earns its best harvest in full sun, where more wood ripens and more nuts fill. It carries on in partial shade, so a part-lit corner still works, but expect a lighter crop from the shadier ground.
Water
Water it steadily through the first two or three years while the roots take hold, and again through dry spells while the nuts are sizing. An established shrub weathers drought well enough, though even moisture always brings a better crop. Let the top half of the soil dry between waterings.
Soil
Set it in deep, well-drained loam with plenty of organic matter, though a hazel is forgiving of 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 robust, cold-hardy shrub that takes winter lows near -31°F (-35°C) and summer heat up to about 95°F (35°C). Its one vulnerability is a hard freeze during the late-winter bloom, which can quietly cost a season's nuts.
Humidity
Ordinary outdoor air, around 40% to 70%, suits it perfectly, so there is no figure to fret over. Airflow through the canopy counts for more, since open growth keeps fungal trouble at bay.
Feeding
Feed it in early spring before bud break, guided by a soil or leaf test rather than by guesswork. A nitrogen-rich balanced fertilizer, applied seasonally, keeps both growth and nut fill on an even course.
Pruning
Prune in late winter while dormant, lifting out dead, weak, and crossing wood and thinning to keep an open center. Cut any blight cankers well below the visible stromata, and clear the basal suckers regularly to hold a clean, composed tree form.
Repotting
As a long-lived landscape and orchard shrub, a hazel belongs in the ground, not in a pot, so it rarely needs repotting. Should you raise one in a container, move it on before the roots circle, the shoots stall, or water runs 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 measure of space from its neighbors so air moves freely and the suckers stay within reach for cutting back.
When to plant
The hazelnut keeps a seasonal rhythm worth planning around. Set new plants out from late fall to early spring while they rest, mark the wind-pollinated catkins that 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 of a hazel's troubles surface in one of three places: the wood, the crop, or the crowd of shoots at its base. Learn to read those cues and you can step in before a small fault unsettles the planting. Match what you see below, then act while the moment still counts.
Branches fading, with rows of raised black bumps along the bark
When a limb starts to fade and rows of black bumps rise along the bark, the culprit is eastern filbert blight, a fungus that girdles the wood over a few seasons. Take out the affected limb a full 2 to 3 feet below the lowest canker, then burn or bin the wood so it can't spread. For a hedge that stays handsome year after year, lean on resistant cultivars and clear away any wild hazels lurking nearby.
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
A generous show of catkins, yet few nuts, or shells that come up empty
A hazel can put on a lovely display of catkins and still set almost no nuts, because it depends on the wind and can barely pollinate itself. A hard freeze during the late-winter bloom can quietly cost the whole crop as well. Plant a second cultivar whose pollen matches and whose bloom overlaps, and choose a spot in the garden where late frosts settle more gently.
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 crowd of shoots rising from the base, drifting toward a thicket
Corylus avellana suckers freely from its base and roots, and without a guiding hand those shoots gather into a dense thicket that overtakes a tidy planting. Cut or pull them while they are still young, returning to the task a few times over the season. A pass with the mower or cultivator around the drip line keeps the spreading shoots from ever settling in.
Fix:
- Cut or pull suckers while young, several times per growing season
- Mow or cultivate around the drip line to sever spreading shoots
Toxicity
For a home that holds pets and children alongside the garden, the hazelnut brings reassurance: it 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 their heavy fat can bring a dog.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
A cat can share the garden with a hazelnut safely, since nothing on the plant is poisonous and a stray nibble of leaf or shell does no harm.
Dogs None
For a dog, the plant itself poses no problem. The nuts are the thing to mind, as a whole one can choke a small dog and the heavy fat can unsettle the stomach or, in quantity, invite pancreatitis.
Horses Safe
A hazelnut set near a paddock brings no poisoning risk to horses, foliage or nuts.
Rabbits Safe
The leaves and twigs hold nothing toxic for rabbits, though the rich, fatty nuts sit poorly with their diet and are best kept out of reach.
Livestock Safe
Cattle, goats, and sheep can share the ground around a hazelnut without any toxic effect.
Birds Safe
Birds come to no harm from any part of the plant, and many a wild one turns up to crack the ripe nuts.
People Safe
The ripe kernels are a familiar pleasure at the table, safe raw or roasted, save for 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
Named hazels are chosen for their blight resistance, their kernel quality, or the character they lend a planting. These are the ones worth knowing by name.
Jefferson
A blight-resistant OSU release grown far and wide for its generous, high-quality kernels.
Yamhill
A compact, early-maturing OSU cultivar that stands firm against eastern filbert blight.
Barcelona
A time-honored Oregon commercial cultivar, though one that falls readily to eastern filbert blight.
Contorta
The sculptural Harry Lauder's Walking Stick, prized for its twisted, corkscrew stems and its 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
The hazelnut lends itself to several methods, from coaxing roots on a low branch to lifting the suckers it offers up unbidden. The path you take depends on whether you want a true copy of a cultivar or are content with a seedling.
LayeringModerate
Late winter to early spring · 1 to 2 years to rooted, separable plants
To keep a cultivar true on its own roots, mound and simple layering are the classic approach. Pin or mound soil over the low shoots in late winter to early spring, let them root over the next 1 to 2 years, and then free them as new plants for another corner of the garden.
DivisionEasy
Dormant season, late fall to early spring · 1 season
The most effortless route makes good use of the suckers the shrub offers up anyway. Lift the rooted basal suckers from an established clump during the dormant season, late fall to early spring, replant them where you'd like another hazel, and they settle in within a single season.
GraftingDemanding
Late winter on dormant rootstock · 1 to 2 years
Grafting sets a named cultivar onto a chosen rootstock and rewards a practiced hand. Work in late winter on dormant rootstock, then allow the union 1 to 2 years to mature 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 a simple pleasure, though it won't reproduce the parent, since seedlings don't come true to cultivar. Sow it outdoors in fall, or chill it cold and moist for 2 to 3 months first, then look ahead to several years of growth before the plant begins to bear nuts.
Myths
A single hazelnut bush will reliably crop on its own.
A single hazel makes a graceful specimen, but Corylus avellana rides on the wind and can barely pollinate itself, so one bush usually sets little or no fruit. A separate compatible pollinizer cultivar nearby is what turns a handsome shrub into a real crop of nuts.
Hazelnut plants are poisonous to cats and dogs.
There's no need to keep a hazel out of a household with pets, since it isn't on the ASPCA toxic list and neither leaves nor nuts will poison them. The genuine cares are choking on a whole nut and stomach upset from the high fat, not any poison.