All Hail the Humble Hazelnut!

By Rebecca Carmien, Master Gardener in Training

Hundreds of thousands of Hazelnut shells were found on a little island in Scotland in 1995 – the largest Mesolithic Hazelnut find ever recorded. The find was radio carbon dated to circa 7000 BCE.  Ancient Chinese text lists it as one of the five sacred nourishments bestowed to humans. We know that Native North Americans used the plant’s wood as a building material, it’s nut as a food source and it’s leaves as medicine. Yet today we don’t hear much about this wonderful and prolific plant. This is why putting Hazelnuts in your yard may be one of the smartest ideas you’ve ever had:

The Hazelnut is considered “woody agriculture”.  As such, they are known to capture and store Co2 from the atmosphere.  Extensive studies tell us that converting traditional food crops to Hazelnuts on a large scale, (called plats), could significantly reduce the carbon footprint of some of our largest farmlands The time and expense of planting and cultivating annual food crops are significantly reduced while heavy water consuming irrigation requirements and damaging chemical treatments for pest control would no longer be required.  Without annual planting there is no disruption of the sometimes fragile life cycles of the songbirds that flock to the Hazel’s sheltering leaves for nesting and safety. Wild life support is diverse and includes dragon and damselflies, moths, turkey, grouse, rabbit, and more.

The hearty Hazelnut has been known to withstand plunges of -40° and continue to produce fruit the next harvest season. Severe heat and drought signals it’s significant root structure to draw water from deep aquifers while other crops wither. Highly adaptable to any soil, it can be planted on a north or south slope, in shade or sun, (although more productive in sun), in wet or dry climes.  Its hardiness zone is steady at 3 to 9. Soil pH requirements can range from acidic to neutral. When planted in poor, erodible soil or marginal cropland at risk of flooding it’s root system holds firm while naturally and slowly filtering rainwater to help clean our water both below and above ground. Nutrient rich topsoil is held in place and enriched each year by deciduous leaf and nut drop.

Reaching heights from 8′ to 12′, (up to 15′, depending on cultivar), with a spread from 8′ to 10′, the dense growth of this hardy perennial can withstand and block damaging winds year round. It doubles as a living snow fence in the winter, especially if planted in rows. A much more economical and ecological friendly fence than any man-made structure ever built. You rarely have to ‘fix’ a living fence.

Of the genus Corylus, the Hazelnut is monoecious and pollinates by wind and wildlife. Pale yellow male catkins grow to about an inch; the female, when visible and not concealed in the bud, are quite small and bright red, both appearing in late summer. In the spring growth cycles resume, reaching up to and above a foot. The leaves, approx. 2 1/2″ x 3 1/2″, are rounded in shape with a pointed tip, doubly serrated with soft hairs on both sides and a rich deep green until early autumn when they begin turning chartreuse, gold and shades of burgundy before they fall. Hazelnuts need others to cross pollinate, (you’ll need three or more), and they can be propagated by root sprout.

Cultivars require about 4 years to fully mature and bear fruit but once established will continue to proficiently produce each and every year, each nut approximately  3/4″ in diameter. One fully grown bush can yield up to 7 pounds.  That’s about 1000 nuts! They grow inside a structure called an involucre, which becomes brown and dry as the nut ripens and are borne in clusters of 2, 3, and sometimes 4. Harvest begins in mid autumn and may continue throughout the fall for as many as three harvests per plant, per season. Nuts can easily and safely be picked while standing on the ground a week or two before drop to keep from animals.

Packed with protein, several vitamins, including significant amounts of vitamin B6, fiber, antioxidants and ‘good’ unsaturated fats, Hazelnuts boast the Heart Healthy Seal of Approval from the FDA. It has applications for both sweet and savory cuisine, can be eaten raw or roasted, ground to a paste or pressed for oil. It’s used as a natural flavoring for sauces, coffees and liqueurs. The market value of the Hazel is high; “Nutella” alone buys 25% of the global supply.  Currently, Turkey raises 75% of the worlds annual crop while Oregon leads in the United States and showed a five year average, (’02 to ’07), of $1,589 per acre.

The benefits of the Hazel do not stop at it’s root’s ability to find and filter water, hold fast and enrich soil, its leaves’ capability to help purify the air we breathe or even it’s nuts food market value. Historically, the branches had specialized uses as Native American drum sticks and forked Hazel branches were valued as divining rods to locate underground water. As an aside, the Witch Hazel, (Hamamelis), was also used for dousing or water witching. The middle English ‘wiche’ is from the Old English ‘wich’ meaning pliant or bendable.  

Today, “Green diesel” production of Hazel oil is another step toward energy independence. Comparison studies show the nut’s oil yield of 1000 kg/ha, (this is a surface density measurement – ‘kilogram per hectare’). That’s almost two times the yield of the soybean! Furthermore, the oil is of a far superior quality. The shells, used as a direct burning fuel, are clean, efficient, and could lessen our never ending need of fuel and use of wood and other more damaging, dangerous and planet depleting energy sources.  

Though the Hazelnut Marketing Board was established in 1949, it wasn’t until 1996 that the Arbor Day Foundation sponsored their research program on a national scale. Interested members were provided with three plants each, asked to keep a journal and make an annual report back to the Foundation on information such as growth rate, nut production and variation, viability and affect of disease or other adverse conditions. In this way, the testing was as widely adverse in zone and condition as possible. Great strides were made in discovering character traits to improve climatic adaptation.

In 2008, the Hybrid Hazelnut Consortium was formed linking land grant institutions including the University of Nebraska, Ohio State University and Rutgers University.  The Consortium combined research investments, intellectual resources and widespread expertise needed to study susceptibility of Eastern Filbert blight and unlock genetic secrets for developing superior hybrids and address any barriers that would restrict or impede large scale Hazelnut expansion in agricultural adoption.

Furthering this study, in 2011 Arbor Day Foundation members were asked to report any wild Hazelnut bushes that were found throughout the United States. Hazelnuts were found where before they were not thought to exist giving a much richer, greater genetic diversity of study than the limited collections that were previously accessible from smaller, controlled and private collections.  Contributing genes of native wild Hazels from across the country greatly expanded the range of study.  Traits such as endurance to cold and heat, resistance to disease, and tolerance to drought & variation were found.

In 2012 the next stage of this ground breaking program was launched; seeds from the best bushes, the ones that were originally sent to members of the Arbor Day Foundation were returned.  From these, seedlings were grown and transplanted on site. Often times, the hybrid Hazelnut produced bigger, superior nuts than either of the contributing parents.  

As a major agricultural crop, it’s clear that the humble Hazelnut is a rising star. If adopted into major agricultural management, its impact could be significant to our ecosystem, our world hunger issues, our land management concerns. We can thank Arbor Day and it’s partners for their research, wisdom and vision.  And with what we have learned, we can plan our own gardens and our back yards to include some really pretty, tasty Hazelnuts. Mine are leafing out beautifully. It’s their first year, they are still small. But great things can begin with one little nut.

For more information on the Hybrid Hazelnut Consortium, or to get information on how to become involved/obtain your Hazelnut bushes, contact:   arborday.org/programs/hazelnuts/consortium.