Planting & Growing Hazelnuts

How do hazelnut trees produce hazelnuts?

Unlike other fruiting trees, the hazelnut tree blooms and pollinates in the middle of winter. Wind carries the pollen from catkins (male flowers) to small red female flowers, where pollination occurs. The flowers remain inactive until spring, when fertilisation occurs and the nuts begin to develop.

The natural growth habit of the hazelnut is a bush, or multi-stemmed small tree as found in Turkey and Southern Europe. In the US, hazelnut trees are grown as single trunk trees that can grow to 5 meters or more.

All varieties of hazelnuts require cross-pollination in order to produce nuts, so every planting requires two or more varieties. In the US, where cultivation and automation exceeds that of Europe, the principal varieties grown are Barcelona (originally derived from Spain in the 19th century), Ennis, Lewis and Casina.

Ennis, a later and heavier yielder to Barcelona, produces a larger nut suitable for both in shell and out of shell production. Lewis produces a medium nut whilst Casina produces a small nut.

Research in Australia is being carried out by the Faculty of Rural Management, The University of Sydney, in collaboration with NSW Agriculture and hazelnut growers. The research is funded by the Rural Industries Research and Development Corporation (RIRDC).

Hazelnut trees should be in commercial production when they are about 6 years old, and a well managed orchard should remain active for 40 years or more.

The nuts mature during the summer months (turning in color from green to hazel) and are harvested in late summer and early autumn when the nuts fall to the ground within a short period. The nuts are picked up by hand or harvested mechanically, washed, dried and sorted by size.

There is very little disease in Australia that harm Hazelnuts due to strict quarantine laws. EFB (Eastern Filbert Blight) is not present in Australia.

The need for pollinizers

Pollinizers are required in Hazelnut orchards because cultivators are self-incompatible. This incompatibility is controlled by a single genetic locus. Hazelnut cultivators are diploid and thus have 2 alleles. If an allele expressed in the pollen is met with the same allele in the female flower, then the cross is incompatible. Pollinizer selection is important. Compatibility charts are available in our publication "Hazelnut Story Part III".

Whilst we recommend at least 20% of pollinizers to the main cultivar in Australia (due to the many growing regions in distance), we recommend that spacing is a more important issue. Hence it is advisable to use 15 - 20 meters as the maximum distance of any main cultivar to a pollinizer.

Where can I grow hazelnuts in Australia?

Hazelnuts are deciduous, requiring a cool winter to provide a sufficient chill to break the dormancy of the flowering and vegetative buds. This crop is best suited to the cooler, southern parts of Australia and the ranges, where summers are not excessively hot. An average annual rainfall of over 900mm is desirable, with supplementary irrigation to overcome moisture deficits in the years of below average rainfall. In the winter and early spring, the female flowers tolerate temperatures down to -9 degrees C.

In Australia, frost has not been noted as a problem, even heavy late spring frosts. Potential production areas in NSW include the Southern, Central and Northern Tablelands, the Southern Highlands and the South Coast. Cooler and higher rainfall areas of Victoria and Tasmania, S.A., W.A. are also considered to be suitable.

What type of soil do I require?

Hazelnuts require a very well-drained soil and orchards should not be located where the soil is poorly drained, shallow, too heavy or too light. Most of a hazelnut tree?s roots are found in the first meter of soil, but soils must be sufficiently deep to allow active root systems to penetrate 2 - 3 meters. Root penetration can be stopped by rock, high water tables or lack of aeration. Hazelnut trees draw moisture from the upper soil layer. No single direction of slope is better than any other, except in so far as it affects soil depth and moisture retention.

The top 60 cm of soil may be dry by mid summer, while the deeper soil may not dry out until the end of summer. Irrigation will be needed to overcome this situation. The greatest benefit of irrigation when establishing an orchard is to obtain large trees more rapidly.

Soil for the hazelnuts should be in the slightly acidic to neutral range. A soil test is a definite requirement before planting