Tuesday, April 10, 2012

Corylus avellana











Corylus avellana in New Zealand is called 'Hazel Nut' and in America it is known as 'Filbert' , which is the way with common names.

We never grew Hazels in Tanzania, but it is a species that could grow in cooler areas. However the reason I want to discuss this species is that it is useful throughout the world and there is a story about it.

The production of hazel nuts was deemed to be a cash crop for people who have such and interest so at the nursery we decided to produce some for sale.
The idea was that roasted hazel nuts, coated in chocolate could be sold at a premium - especially targeting the Japanese market.
The 'demand' was that the nuts should be of a large, even size. So cultivars were produced and one called 'Whiteheart' was deemed to be the best. But the variety did not pollinate well because of the different ripening times of the male and female flowers. Several varieties of pollinators were identified.

We sought guidance from the academics Lincoln University and they could provide cutting material. Corylus avellana is difficult to propagate from cuttings, and were were advised that the cuttings needed to be set into trays at the very earliest instance. The cutting material was from suckers.
The first year we took the cuttings and packed them in water-retaining crystals and set the cutting into trays back at the nursery. Then sat them on heat and under mist. Out of all that, the result was a 10% take. Very expensive plants indeed, especially so because Lincoln University is some 300 km from the nursery and workers needed to be accommodated and fed.

The next few years, we ran a ferry service of filed trays to Lincoln where the cuttings were set and ferried back to the prop house at the nursery - all on the advice of the academics - but all very expensive. The take was not improved by doing this and the cost of production had to be subsidized by other crops. The pollinators were doubly difficult to produce and the cutting material was not available in good amounts.

When I returned from Tanzania the production of Corylus avellana was still lower than demand and the method had not improved. Below is the method I devised that results in a take of around 90%.

But I'm not all that sure that 'Whiteheart' are any better than than other varieties and for sure do not produce a large nut.
I like all nuts and particularly enjoy hazels, but I'm not much of an expert on confectionery. Those Ferrero Rocher chocolates are a testament to marketing with tiny hazel nuts that I would probably reject - and for me they do not rate when compared to chocolate scorched almonds!
So big nuts are not all that important when it comes to confectionery.

Description: A shrub or small deciduous tree up to 3 m. Many branched and often with suckers. Growing tips hairy. Bark is greyish and smooth - growing tips green. Leaves ovate and toothed >10cm but often smaller. Mid green. Make flowers are drooping catkins and female are inconspicuous, small, green. Nuts are in winged husks that open to reveal a hard shelled nut - sometimes in clusters of up to 4.

Uses: Mainly known for nut production, but provides good, low shelter shelter. Hot burning fuelwood and coppices well.

Propagation:



Well the pic isn't all that clear.

Grow stool plants and allow suckers to start. Place over two old car tyres and fill with sawdust [or other media]. It is reasonable to wound the suckers.
After the growing season, remove the tyres and strip away the media. This reveals rooted suckers that can be cut off and potted on.

Otherwise plants are produced by growing the nuts as a seed - I usually crack the hard shell.

Here in New Zealand aphids are attracted to the leaves but do not seem to do harm. However the aphids are able to move on to other plants.
In production orchards the suckers become a problem and are removed when small by using a chemical desiccant.

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