Shrub · Betulaceae
Hazelnut
Corylus avellana
Give it full sun, a pollen partner, and room to spread, and the hazel keeps the nuts coming every 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, thriving across Europe and into western Asia. Cobnut, filbert, take your pick of names, this plant delivers on two fronts: a dependable autumn haul of edible nuts and a suckering habit that makes it a natural for a hedge or an orchard edge. Hardy from zone 4 to 8, it powers through cold winters that would flatten a softer tree.
It kicks off the year early, flowering well before the leaves when pale yellow catkins swing from bare late-winter branches. The wind carries the pollen, not the bees, and that's the very reason a lone bush hardly ever fills a crop. Most hazels are largely self-incompatible, so pair yours with a second, compatible cultivar close by and the female flowers get to work setting nuts.
Grow it well and a hazel turns into a long-lived, low-fuss producer. Two moves make all the difference: reaching for blight-resistant cultivars and keeping ahead of the suckers that keep firing up from the base and roots all season. Nail those and the shrub holds a clean form for decades.
Care
The short version: plant it 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 clearing the suckers and any blight.
Light
Hazelnut crops best in full sun, which ripens more wood and packs in more nuts. It'll cope with partial shade and keep growing, but a shadier spot brings a lighter harvest.
Water
Water it regularly through the first two or three years while the roots dig in, then again during dry spells while the nuts are sizing up. Once established it takes drought fairly well, though steady moisture always drives a better crop. Let the top half of the soil dry between waterings.
Soil
Give it deep, well-drained loam packed with organic matter, though hazel handles 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 tough, cold-hardy shrub barrels through winter lows near -31°F (-35°C) and summer heat up to about 95°F (35°C). Its one weak spot is a hard freeze during the late-winter bloom, which can cost that year's nuts.
Humidity
Ordinary outdoor air around 40% to 70% suits it, so there's no number to chase. Airflow through the canopy matters far more, since open growth keeps fungal trouble down.
Feeding
Feed it in early spring before bud break, working off a soil or leaf test instead of guessing. A nitrogen-rich balanced fertilizer, applied seasonally, keeps growth and nut fill firing.
Pruning
Prune in late winter while dormant, clearing dead, weak, and crossing wood and thinning to keep an open center. Cut any blight cankers well below the visible stromata, and pull the basal suckers regularly to hold a clean tree form.
Repotting
Hazelnut is a long-lived landscape and orchard shrub that lives in the ground, not in pots, so repotting rarely enters the picture. Start one in a container and you'll want to move it on before the roots circle, the shoots stall, or water runs straight through the mix.
Size & spacing
A mature hazel shoots up to 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 you've got space to cut the suckers back.
When to plant
The hazelnut runs on the dormant season, so lean into that rhythm. Get new plants in the ground from late fall to early spring while they rest, catch the wind-pollinated catkins swinging open in late winter, and then 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 pops up in one of three spots: the wood, the crop, or the crowd of shoots at the base. Learn to read those signs and you can jump in fast, before a small hiccup gets bigger. Match what you see below, then act while it counts.
Branches dying back with rows of raised black bumps along the bark
Those football-shaped rows of black bumps mean eastern filbert blight, a fungus that marches along the bark and girdles the wood over a few seasons. Get ahead of it: cut the affected limb 2 to 3 feet below the lowest canker and burn or bin the wood. Then plant resistant cultivars and pull out any wild hazels lurking nearby, since those keep the fungus in the game.
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 big catkin show but hardly any nuts, or shells that come up empty
A hazel can throw a dazzling catkin display and still set almost no nuts, because it runs on the wind and can barely pollinate itself. A hard freeze during that late-winter bloom can knock out the catkins or female flowers too. Team it up with a cultivar that sheds matching pollen and blooms at the same time, and tuck the plants where late frosts land softer, and the nuts follow.
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
Shoots charging up from the base and roots into a thicket
Corylus avellana suckers freely from the base and roots, and those shoots will race into a thicket if nothing stops them. Stay on top of it: cut or pull the young suckers a few times through the season and the plant keeps its shape. Running a mower or cultivator around the drip line snaps off the spreading shoots before they dig 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
Great news for a home with pets and kids: the hazelnut is not poisonous. No part of the plant is listed as toxic, and the ripe kernels are a food you already enjoy. The only things to keep tabs on are the choking risk of whole nuts and the upset all that fat can hand a dog.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Cats have nothing to fear here, since no part of the hazelnut is poisonous and a curious nibble of leaf or shell passes without harm.
Dogs None
Dogs are fine around the plant itself. The nuts are where to stay sharp, because a whole one can choke a small dog and the high fat can churn up the stomach or, in big amounts, stir pancreatitis.
Horses Safe
Horses run no poisoning risk from hazelnut, foliage or nuts alike.
Rabbits Safe
The leaves and twigs carry no toxins for rabbits, though the rich, fatty nuts miss the mark for their diet and should be kept clear.
Livestock Safe
Cattle, goats, and sheep can browse right around a hazelnut with zero toxic effect.
Birds Safe
No part of the plant harms birds, and loads of wild ones show up to crack the ripe nuts.
People Safe
The ripe kernels are a well-loved food, safe raw or roasted, apart from anyone carrying 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 picked for their blight resistance, kernel quality, or looks. Here are the standouts worth knowing by name.
Jefferson
A blight-resistant OSU release that growers reach for everywhere thanks to its big, high-quality kernels.
Yamhill
A compact, early-maturing OSU cultivar that shrugs off eastern filbert blight with strong resistance.
Barcelona
A classic Oregon commercial cultivar, though it catches eastern filbert blight all too easily.
Contorta
The eye-catching Harry Lauder's Walking Stick, grown for its twisted, corkscrew stems and standout 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 takes off with several methods, whether you're rooting a low branch or scooping up the suckers it hands you for free. It all comes down to whether you want a spot-on copy of a cultivar or you're glad to grow a seedling.
LayeringModerate
Late winter to early spring · 1 to 2 years to rooted, separable plants
To copy a cultivar on its own roots, reach for mound and simple layering. Pin or mound soil over the low shoots in late winter to early spring, let them build their own roots over the next 1 to 2 years, then snip them loose as fresh new plants.
DivisionEasy
Dormant season, late fall to early spring · 1 season
The quickest win is to grab the suckers the shrub keeps handing over. Lift the rooted basal suckers from an established clump in the dormant season, late fall to early spring, replant them, and they take hold within a single season.
GraftingDemanding
Late winter on dormant rootstock · 1 to 2 years
Grafting joins a named cultivar to a chosen rootstock and rewards a steady hand. Work in late winter on dormant rootstock, then give the union 1 to 2 years to build 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 fun place to start, but it won't copy 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 settle in for several years of growth before the plant starts pumping out nuts.
Myths
A single hazelnut bush will reliably crop on its own.
Tempting to hope, but Corylus avellana runs on the wind and can barely pollinate itself, so one lone bush usually sets little or no fruit. Bring in a separate compatible pollinizer cultivar nearby and a real crop of nuts finally kicks off.
Hazelnut plants are poisonous to cats and dogs.
Nope, since the plant isn't on the ASPCA toxic list and the leaves and nuts won't poison a pet. Keep your eye on choking from a whole nut and stomach upset from the high fat, not poisoning.