Jepson (2012) (APG System)

Order

Fagales

Family

Betulacaeae

Jepson (1993) (Cronquist System)

Order

Fagales

Family

Betulaceae

Plant Relationships

California Species:

Corylus cornuta var. californica

Western hazelnut

Other Species:

Corylus americana
Corylus avellana

American hazelnut (E US)
Filbert (europe)

Description

Growth Forms:

Corylus are described as small trees or large shrubs.

Branching:

Alternate branching

Leaves:

The leaves are simple, with a cordate base. They have serrate margins and are covered with velvety hairs. The hairs can cause itchiness and minor skin irritation.
The leaves are deciduous.

Flowers:

The flowers are in catkins, which emerge and open in mid-winter.

Fruit:

The hazelnuts look like small acorns with a papery husk. Seeds ripen in August. They are eaten by deer and collected by rodents. If you want to collect them, get there first.

Growing Conditions

Natural Range and Habitat:

Corylus cornuta grows throughout northern California in the Coast Range as well as the Sierras and Cascades. Hazelnut extends northward into Oregon, Washington and British Columbia. It is common in the Bay Area under coast live oak, especially near the coast. However, they grow in the Ponderosa pine forests and Lodgepole pine forests as well.

Sun and Exposure:

Hazelnuts are shade tolerant. They are typically found growing under the canopy of other trees, such as coast live oak. They do not produce much seed in the shade. If you want the plants to produce abundant seed, plant them in the sun. You must ensure, however, that there is adequate residual moisture in the soil during the summer to sustain them. It is worthwhile to plant them in the sun on an eastern or northern facing slope where the sun is less intense. Also, the closer to the coast and cool temperatures, the better.

Soil and Moisture:

Hazelnuts grow in sites with available summer moisture, but they don't grow in wet soils. They are often found on east and north facing slopes where there is reduced moisture stress.
Hazelnut benefits from irrigation, and shows no ill effects from it.

Horticulture and Restoration

Horticultural Comments:

This is a medium to small tree that makes a great addition to the landscape. If left alone, it will generate many small branches, but it is easily pruned into a very attractive form.

Wildlife Habitat:

The seed, ripens in August, is highly prized by wildlife and humans alike.

Restoration Projects:

Hazelnut is rarely used in restoration projects, probably because it does not dominate the areas where it lives. It is found in nature as an understory tree, rather than the canopy. People tend to overlook it.
It would be a very reliable tree in outplanting project, if used in an appropriate location. This would be a woodland or forest location where the is reduced sunlight intensity and reduced moisture stress. I am not talking about wet or boggy soil, simply a low stress location in a woodland.