Hazelnut Tree: Filberts Or Hazelnuts Galore

When it comes to nuts, one of the most beloved is the filbert or the hazelnut. Used in baking, spreads, and in desserts combined with chocolate, the buttery taste of the American hazelnut just can’t be beaten. And you (yes, you!) can grow your very own hazelnut tree at home. 

In this piece, we’ll cover three members of the Corylus genus: Corylus americana, C. avellana, and C. maxima. Although there are many hazelnut varieties out there, these three are most prevalent in North America. Knowing how to care for these hazelnut trees leads to abundant crops of flavorful nuts. 

While container gardening these nut trees isn’t the best option, those who have space can plant the trees in an area with enough feet in between. That means even people with 20 foot by 20-foot outdoor spaces can grow multiple trees at once. And due to the necessity for cross-pollination, they’d do well too!

So let’s cover the ins and outs of growing hazelnuts at home!

Good Products At Amazon For Growing Hazelnuts:

• Monterey BT Caterpillar Killer
• Neem Bliss 100% Cold Pressed Neem Oil
• PyGanic Botanical Insecticide
• Captain Jack’s Dead Bug Brew (spinosad)
• Southern Ag Liquid Copper Fungicide
• MycoStop Biofungicide

Quick Care Guide

Common Name(s)	Hazelnut, filbert, American hazelnut, common hazelnut
Scientific Name	Corylus americana, C. avellana, C. maxima
Days to Harvest	About 40 days from flowering
Light	Full sun to part shade
Water	1 to 2 inches per week
Soil	Light, slightly alkaline, well-draining
Fertilizer	Slow-release nitrogen in spring
Pests	Filbert worm, nut weevil, squirrels, ruffed grouse
Diseases	Root rot, eastern filbert blight, bacterial blight, bacterial canker, hazelnut mosaic virus

All About Hazelnut Trees

Again, this piece zones in on the three Corylus species: americana, avellana, and maxima. They are known commonly as American hazel, common hazel, and filbert, respectively. In general, the hazel tree is a member of the birch family native to the northern hemisphere. Corylus americana is native to the central and eastern United States. Corylus avellana is native to western Asia and Europe. C. maxima is native to southwestern Asia and southeastern Europe. 

Hazelnut remains have been found in stone-aged archeological sites from northern Europe to China. It’s believed that the tree spread throughout the world during the ice age. The European tree made its way to North America in the 19th century during the horticultural boom. It then became an important tree for nut production. But we would be remiss to not mention that hazelnuts are a staple in Turkey, where 60 to 70% of the world’s hazelnuts are produced. 

The hazelnut tree is a deciduous multi-stemmed shrub, reaching up to 15 feet and spreading anywhere from 5 to 10 feet. C. maxima, or filbert trees, reach up to 30 feet tall. For those who have less space, planting an Corylus americana or Corylus avellana species is best. The leaves of these shrubby fruit trees are green and rounded, with serrated edges that are 1 to 3 inches wide and 2 to 4 inches long. Filbert trees have purple leaves. 

Flowers bloom on the tree in very early spring in either yellow, male catkins or tiny red female blooms. Cross-pollination between male and female flowers helps to produce nuts in higher volumes. Most varieties are self-fertile and self-pollinate on the same plant. Hazels form as a result of female flower pollination and mature within 40 days from pollination. They are formed within a husk and are ready in early fall. The roots of these trees are long, branching taproots. 

Gardeners in the United States might want to skip attempts to grow avellana, or European hazelnut trees due to their high incidence of Eastern filbert blight. Those with less room would do well to stick to the American hazelnut instead of filbert due to spacing issues. First harvests also don’t occur until the tree has been established, after about 5 years. Full harvests occur around 9 years when up to 25 pounds of edible nuts can be harvested from a single tree.

The wood of hazelnut trees is especially useful for those who like to make fencing, furniture, and trellises. The oil is used in beauty products, and the twigs can be used for animal fodder. It’s a great source of pollen for bees early in spring. There’s so much that can be done with this small tree. And it’s a host for lichen, and fungus that have developed a symbiotic relationship with the tree over time. 

Planting

Plant your nut tree in late winter when it’s still dormant. Remember that planting just one tree can reduce the number of nuts you harvest in the long run. Planting in the heat of summer will shock tree roots. Select a site for your hazelnut trees that are 15 to 20 feet apart. If you’re planting filberts stick to the wider side of that range. They need a sunny area with well-draining soil. Dig a hole that’s deep enough for the root ball and twice as wide. Wet the roots of the tree thoroughly. Then plant the roots in the hole, allowing the top part to be level with the soil line. Return soil to the hole, tamping it down as you go to remove air pockets. Add two gallons of water when the hole is 75% full. Then top with the remaining soil, mounding it up at the base, leaving a couple of inches between the trunk and the surrounding soil. Mound layering helps promote good drainage. 

Care

With a good foundation for your plant, you won’t have to do much to have a harvest of your own nuts in time. So let’s discuss the basic tenets of that foundation. 

Sun and Temperature

Hazelnuts need at least 4 hours of full sun per day. In hotter areas with intense direct sunlight, partial shade can remediate too much heat and sun. European hazelnuts are better suited for colder regions of USDA zones 4 to 8. American hazels can handle warmer temps. Filbert trees thrive in all of these hardiness zones. Temperate weather in the middle of these hardiness zones leads to higher production of female and male flowers, which leads to more nuts produced. In colder months, the ideal temperature for this small tree is 50 degrees Fahrenheit. 

In hotter months, they thrive at 85 degrees. They don’t appreciate hot and dry conditions for extended periods. The same goes for frosty areas. Colder temperatures under the ideal range will kill female flowers before they can be pollinated. They will drop flowers in high heat situations without adequate sheltering and moisture. Mulch and covering will keep the soil warm in a cold snap. Adequate moisture and shading will help when growing trees in hotter regions. 

Water and Humidity

Water your hazels in the morning with a gallon of water every few weeks. Do this with drip irrigation or a soaker hose, ideally. Otherwise gentle irrigation via a watering can at the base of the tree works well. Increase that amount to every other week during the fruiting period of growth. If it rains often, there’s no need to add extra irrigation. American hazelnuts are drought-tolerant. 

Soil

Hazels can grow easily in poor, well-draining soil, but they produce best in a home landscape with good soil. In areas with exceptionally poor soil, add a little potting soil or compost to the existing earth. American filbert enjoys a neutral to slightly alkaline soil pH ranging from 5.5 to 7.5. 

Fertilizing

American filbert does not need any fertilizer, though some guides suggest a slow-release, high-nitrogen, granular fertilizer in the second year of growth to help produce foliage. Nitrogen fixers planted in conjunction with your tree assist in poor soils. Use fertilizers at the soil line at an NPK of 4-3-0. 

Pruning

Prune regularly to promote bushy growth. Remove suckers that may crop up from the base of the plant. In commercial production, hazels are pruned in winter to promote branching in the growing season. It’s at this time that hazel has no leaves due to its deciduous nature. Remember that female flowers form nuts on this multi-stemmed shrub that is self-fertile, so leave branches from last year’s growth to allow the female parts to grow. Male catkins grow from the current year’s growth. Remove crossing branches and those that grow toward the trunk as well. If you remove longer branches from your American hazelnut, they can be formed into trellises, furniture, or baskets. We’ll talk more about harvesting native nuts from the tree in the harvesting section below. They automatically drop from the tree when ripe. 

Propagation

There are two reliable modes of propagating American hazelnut: by seed and by sucker. To plant an American hazelnut, gather the nuts you’d like to plant and test their viability in water. If they float, use them for food. Those that sink can be planted in a basic potting mix after they’ve been slightly scarred via sandpaper or a nick from a knife. Plant the seeds 1 to 2 inches deep and place them outdoors for cold stratification. If winters in your area are particularly cold, place the seeds in a bag with sand in the freezer for 1 month. Then plant them in starter pots. In about 30 days, you’ll have a hazelnut sprout. 

To propagate suckers, remove the plant from the ground with the root intact. Then transplant the main stem into another area of the garden in a warm place. Mound soil around the base and you’ll have a new American hazelnut tree in a couple of weeks. Do this in late fall or early spring. 

Harvesting and Storing

The best part about growing filbert? Hazelnuts! Let’s discuss harvesting and storing this food staple crop. 

Harvesting

After the fruit first forms, hazelnuts are mature and ready within 4 to 6 weeks. Harvest time is generally in late summer to early fall. You’ll know it’s time to harvest when the papery husks turn yellow. Either remove them from the tree by hand or let them drop to the ground and gather your harvest from there. Alternatively, you can pick them early to stave off squirrels and ruffed grouse. Then allow them to dry in onion bags in a dark, warm room with good air circulation. Note they will have about a third of the shelf life if you pick them early. For either ripe or unripe hazelnuts, dry them in a single layer on a rack indoors for several days.  

Storing

Whole hazels keep in a cool dry place for six months to 1 year. They’ll keep up to 2 years in the refrigerator. An airtight container will increase shelf life. Shelled hazels stored at room temperature keep for 3 to 4 months. Keeping them out of sunlight is important because the sun breaks down the flesh of the nut faster. Both shell-on and shelled filberts in raw or dehydrated formats keep in the freezer in plastic freezer bags for 2 years. Hazelnuts roasted on an open fire keep in the refrigerator for 6 months and 1 year in the freezer. 

Troubleshooting

Let’s talk about crop loss, pests, and diseases that can affect your hazelnuts. A close eye on these will help you in the long run. 

Growing Problems

Filberts don’t appreciate high winds or excessive heat or cold. In hot conditions, provide shade and water to keep the roots cool. Mulch is also a must. A windbreak is necessary to stave off winds. 

A cold snap won’t damage the tree, but prolonged cold will result in damaged male catkins, and subsequent crop loss. Mulch and frost cloth can help in a long cold period. 

Hazel can also suffer crown issues if suckers aren’t removed as they crop up. This will also divert nutrients to suckers rather than the main plant. Remove them and give them away as gifts to friends who might also want to grow these lovely nuts. 

Overwatering can weaken the plant, and provide optimal conditions for fungal and bacterial diseases to proliferate. Allow the soil to dry out between waterings, and don’t water more than every few weeks in the regular season. 

Pests

The filbert worm is the larva of the acorn moth. It loves to feed on the hazelnuts and burrows into the shell to reach the tasty nut flesh. As it consumes the nut, it makes way for invasions of bacteria and fungi to infect the tree. Look for small holes in the fruit to determine whether they are on your tree. Encouraging bats via a bat house on a tall structure in the area may keep the moths at bay. Keep the grass around the filberts mowed to prevent larval overwintering. You can kill the moths with a pheromone trap as well. Treatment options include bacillus thuringiensis, neem oil, kaolin clay, pyrethrin, and spinosad.

Filbert weevils are cute, but they will also burrow into the hazelnuts with their long, thin, proboscis. They’ll feed on flowers and leaves too. Look for small holes in fruits, leaves, and flowers to determine whether or not they are present. Larvae of the weevil tend to overwinter on the shadier side of the ground around the filbert base. Promptly remove all nut debris as soon as possible after it drops to culturally control them. Also, keep an eye on local oak trees, as the filbert weevil can also be a pest on oaks (and their acorns). There aren’t currently any insecticides that are consistently effective against these weevils. 

Squirrels! If you’ve gardened for any amount of time, you know how menacing they can be, and they love nuts. The best way to keep them out of your hazelnuts is to harvest early and allow them to ripen in the way suggested in the harvesting section. Otherwise, tie mesh bags around the nuts and hope squirrels don’t break into them. This will also keep hazelnuts from sprouting all around your yard where squirrels buried them. 

Ruffed grouse is a bird that loves hazelnuts. If you have enough room, you can create a ruffed grouse habitat in your yard by planting multiple hazelnuts. They enjoy feeding on all parts of hazels: nuts, flowers, and twigs. If you lose a good portion of the flowers to grouse, no problem. They’ll come back next year. The thing you want to control for the most in this situation is tent caterpillars. They are the main source of food for the grouse. Use Bt (Bacillus thuringiensis) sprays at the beginning of the growing season to prevent caterpillars. Netting around the tree can prevent the grouse from feeding on it as well. 

Diseases

Root rot is a fungal condition that occurs on hazels when the ground has been wet for too long. Resistant varieties are less likely to be susceptible to the disease. However, affected plants will show leaf discoloration and dropping, as well as fungal growth at the trunk of the plant. Ensuring your tree has good drainage around it will prevent most forms of root rot. A few root rot types can be prevented with a biological fungicide that uses microbial life to eliminate fungal causes. Once the roots begin to rot, you are likely to lose the tree and should consider removal.  

Eastern filbert blight is a fungal disease caused by the pathogen Anisogramma anomalae. It causes cankers on the branches at the top of the plant which spread and cause wilt and dieback of branches. As soon as a canker arises, remove the affected branch along with two feet below the canker area. Remove any volunteers that grow to prevent spread. While there are no fungicides that will completely eliminate the disease, copper fungicides have been used quite well as a form of prevention. Still, resistant varieties are the best mode of control. 

Bacterial blight also causes branch dieback but involves necrosis instead of cankers at first. The inner tissue of branches will rot out from a reddish lesion that can eventually cause cankers on other parts of the tree. Water properly, and provide well-draining soil to prevent blight. Copper bactericides applied in spray form after harvest and before fall rains two times per year can control it as well. 

Bacterial canker causes bud break and withered spring growth. The dead leaves remain, and cankers form at the base in a light gray color. Remove affected branches as soon as symptoms manifest. Then, spray a copper fungicide or Bordeaux mixture after harvest and before fall rains two times per year. 

Hazelnut mosaic virus presents as banding on the trunk and leaf veins. It will reduce the yield of hazelnuts. If you notice any of these symptoms, consult your local agricultural extension office to determine the best course of action for this highly infectious disease. Mosaic viruses have no treatment presently and are usually spread through insect vectors.

Frequently Asked Questions

Q: Do you need 2 hazelnut trees to get nuts?

A: It’s not absolute, as most trees are self-fertile, but you’ll increase your yield by cross-pollinating at least two trees. 

Q: How long does it take for a hazelnut tree to produce fruit?

A: After about 5 years, the tree will begin fruiting. 

Q: Can you eat hazelnuts straight from the tree?

A: Dry them for several days at first, then enjoy!