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 completes 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 metres 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 compared 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.
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 are very few diseases or pests in Australia that harm Hazelnuts, due to our strict quarantine laws. For example; a significant problem disease affecting the USA hazel crop, Eastern Filbert Blight (EFB), is not present in Australia.
The need for pollinisers
Pollinisers are required in Hazelnut orchards because the cultivars are self-incompatible. There must be enough genetic difference between the pollen providing variety(male), and the main nut producer(female) for fertilisation of the flower, and subsequent production of a nut, to occur.
Thus polliniser selection is very important. There is some detail on compatible varieties on our sales page, and further information in our sales literature booklet "Hazelnut Story Part III".
Whilst we recommend a ratio of at least 20% of pollinisers to the main cultivar, in Australia, we find that spacing is also a relatively important issue. Hence it is advisable to use 15 - 20 metres as the maximum distance from any main cultivar to a polliniser.
Where can I grow hazelnuts in Australia?
Hazelnuts are deciduous, requiring a cool winter to provide 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 available 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 Celsius.
In Australia, frost has not been noted as a problem, even where there are late, heavy spring frosts.
Potential production areas are the cool and high rainfall areas of NSW, Victoria, Tasmania, and certain areas of S.A. and W.A.
Climate data evaluation forms part of our consultation process for commercial plantings.
What type of soil do I require?
Hazelnuts require a very well-drained soil. Orchards should not be located where the soil is shallow, too heavy or light, or poorly drained.
Most of a hazelnut trees roots are found in the first meter of soil, and hazelnut trees draw moisture primarily from the upper soil layer. But soils must be sufficiently deep to allow active root system penetration two to three metres to provide the structural strength to resist wind damage. Root penetration can be stopped by rock, high water tables or lack of aeration. No single direction of slope is better than any other, except in so far as it affects soil depth and moisture retention.
Soil for the hazelnuts should be in the slightly acidic to neutral range. A soil test is a definite requirement before planting
Irrigation is beneficial when establishing an orchard to obtain large trees more rapidly. Later its main use is countering any excessively dry conditions during the nut filling stage.
The top 60 cm of soil can be dry by mid summer, while the deeper soil may not dry out until the end of summer.
The nuts are filling the shell December through February and it is therefore very important they have sufficient surface moisture during this period. Irrigation will be needed to overcome any drying of the surface soil during summer.