Hazelnuts

Hazelnuts, filberts, or cobnuts, whatever you call them, these delicious nuts grow on trouble-free shrubs that make excellent additions to your foodscape. Since hazelnut shrubs naturally grow alongside creeks and under taller overgrowth, they are a good choice for locations with partial shade.

Hazelnuts (Simon A. Eugster) CC BY-SA 3.0

Why grow hazels?

The obvious reason for growing a hazel bush is the delicious nuts. Hazelnut plants can produce food for 80 years! Hazelnut shrubs also make excellent, drought tolerant anchor plants in the landscape. Traditionally, hazels were planted as hedgerows between properties and grazing fields. They were frequently coppiced, or cut to ground level to stimulate new growth, to provide long, slender poles for basket-making and wattle and daub fencing.

Hazelnut classification

Some scientists group the hazels with birch trees, while others claim hazels are their own grouping. All hazels are from the Corylus genus and all of their nuts are edible. Worldwide, there are 14 to 18 species. Only two species are native to North America, with one local variation:

• ​Corylus americana - American Hazelnut; native to Eastern U.S.; up to 16’ tall shrub
• Corylus cornuta - Beaked Hazelnut; native to North America; 15 to 20’ tall shrub
• Corylus cornuta var. californica - subspecies native to northern California; slow-growing, 8 to 18’ tall 

The cornuta varieties are called ‘beaked hazelnuts’ because the nuts’ outer covering has a beak shape. Our native varieties are smaller than their European cousins, which can reach  a mature height of 30 feet. European varieties tend to produce larger fruit with thinner shells.

How hazels grow

Beaked hazelnut (USDA-NRCS PLANTS Database) Public Domain

Unlike most plants, hazelnuts bloom and pollinate in winter. Yellow pollen-crusted catkins release their bounty to the wind, which carries it to tiny red flowers. There, the pollen stays dormant until summer. That’s when the nuts start to form.

Hazels are monoecious, or hermaphroditic, having both male catkins and female flowers on the same plant. Catkins are hanging flower clusters that contain pollen. Hazelnuts are self-infertile, which means you will need more than one plant to produce a crop of edible nuts.

Members of the hazel family are all deciduous. Some are trees and some are suckering shrubs. These suckers can be used to to create new shrubs elsewhere on your property or given to family and friends to start their own. Commercially, the suckers are generally removed and the shrub is trained into a tree form, to make management and harvest easier. What you do with yours is entirely up to you, but it is nice to have options!

How to grow hazelnuts

If you have access to suckers, use them! Otherwise, you can plant nuts in loose soil and water occasionally. Germination rates and speed can be increased by scarification, or scoring the outer layer of the nut. Once seedlings are 12 inches tall, they can be transplanted to their permanent location. They will begin producing nuts in their 3rd or 4th year. These nuts grow in clusters called burrs.

Hazels are shallow-rooted plants that cannot tolerate soggy ground. They are drought tolerant and require little effort on your part, once they are established. Only during the peak of hot summers do they need any irrigation.

Hazelnut pests and diseases

One very serious threat to hazelnuts has kept them from being grown commercially in the Eastern U.S. It is called eastern filbert blight. Our native species are resistant, and some are immune. This disease has recently made its way west to Oregon and California. Pests include bud mites, jay birds, and squirrels. Ads claim that giant eye floating balloons are a good way to keep birds out of fruit and nut trees, but I was unable to find any research that verified those claims.

Harvesting hazelnuts

Hazelnut harvesting begins in autumn, as the leaves and burrs turn brown. Remove nuts from the burrs and lay them out in a single layer, in a protected area, to dry for a few days. Roasting makes it easy to remove the inner paper, which can taste bitter, and it brings out that rich hazelnut flavor that we all know and love!