HGA newsletter, January 2004
In this issue Murray Redpath of “Wairata Hazels”, near Opotiki, is sharing some of his vast experience of Hazelnut growing with us.
Wairata Hazels is part of Wairata Forest Farm, a 575 hectare property in the hills of the Eastern Bay of Plenty.
Historically the property has been run as a sheep and cattle farm with occasional income from wild animals (deer, opossums), tourism, and forest products (primarily native timber).
Hazels were first planted in a small (0.3 ha) experimental block from 1982-1989 (the Variety Block) with a further 1 hectare planted in 1989 and 1990.
Hazels have been propagated for sale since 1985.
Since 1995 we have had a vision of hazels becoming a significant part of the New Zealand horticultural industry, characterized by our slogan, “Hazelnuts: Delicious, Nutritious, and Versatile.” In 2003 we leased out most of the property to concentrate our resources towards achieving that vision.
Climate is wet (2000-2500mm rain annually) with very few frosts in some winters. Soils are free draining sands or sandy loams derived from alluvial and airfall volcanic ash. Natural fertility is low.
Nutrients leach freely out of the soils so we apply fertilizer (usually Nitrophoska) as split dressings from bud-burst through to December. This year we are spraying a balanced liquid fertilizer on varieties with heavy crops to try to maintain high nutrient levels in the leaves and avoid the poor crop that inevitably follows a heavy crop.
Boron is applied as a foliar spray with 2 applications during October.
The moist climate causes quality problems with varieties that have fibre on the kernel or get mouldy kernels. Consequently we have difficulty achieving good kernel quality on most of our high yielding varieties (including Ennis and Butler in some years) and need to plant varieties with clean, fibre-free kernels such as Plowright, Whiteheart, and Appleby.
The Variety Area
The first planting consisted of 2 rows each of Appleby (called NZ Barcelona back then) and White-skinned Filbert. Subsequent plantings were of as many different varieties as I could find, planted at a 5×3 metre spacing. The block was fertilized but received no sprays for pests and diseases. Pruning was limited to sucker removal. The idea was to let the trees develop naturally and find out as much as possible about how they grew and what attacked them
Until 1995, the best varieties in this block produced well (yields comparable to the hazel trial at Lincoln) Since then, shading has steadily reduced yields. In 2000 we began to experiment with pruning methods to rejuvenate the block and will prune the remaining trees this winter. After 20 years, the trees are large. Vigorous varieties (Barcelona, M.de B.) are over 8 metres tall and even Whiteheart is about 6 metres in height.
From my work in this block, and in old orchards in HawkesBay and Wairarapa, I think that the most economical way to rejuvenate old trees is to get the chainsaw out and cut everything back to the main framework branches. At a 5×3 spacing, the trees should be cut to no more than 3 metres high with a clean 2 metre gap between the rows
This area is to be retained as a store of hazel genetic material. Spare trees of non-commercial varieties, such as White-skinned Filbert, will be removed and replaced by new material I am breeding and collecting from old orchards around NZ.
The Main Block
One hectare planted with the varieties that appeared to be most suited to our area according to our trial results up to 1989.
Planted mainly in Whiteheart in a range of spacings from 5×3 to 4×1 metres. Other varieties, planted at a 5×2 metre spacing, were Plowright, Tonda Romano, Qu.409-2, and W88-3 (probably a Whiteheart/Merveille de B. cross from Hawkes Bay also called Maxine’s Choice).
Growth in this block was rapid (up to a metre of new growth on Whiteheart each year) and shading was soon a problem at the close spacings. The close spacings are to managed as hedgerows to look at pruning techniques for intense planting systems.
For low vigour varieties such as Whiteheart, I now favour a 4×4 metre spacing in good growing conditions.
Qu.409-2 and Gisborne (planted as a pollinator) have given the highest and most consistent yields. Tonda Romano and Whiteheart vary according to the seasonal conditions. The lack of late pollinators in this block, especially the absence of Alexandra, is limiting the crops of late flowering varieties, especially Plowright and W88-3 which do not seem to be pollinated by Keen’s Late.
Big Bud Mite is not a problem here as they do not like damp conditions. The main insect pest is the Green Shield Beetle (Stinkbug, Bean Bug) that feeds on the nuts close to harvest and turns the kernel bitter. Unfortunately the hazel harvest coincides with the peak population of this bug. Solutions are to keep the orchard and surrounding land very clean to limit the ability of the population to build up. Because we are surrounded by native bush, we will always have a re-infestation problem so we plant small areas of the orchard with crops such as mustard that the beetles prefer and we will spray these regularly.
The lemon tree borer and Puriri moths can also cause problems.
Hazel blight lowers yields on susceptible varieties such as Qu.409-2 and Ennis in very humid seasons such as this year. We do not consider that it is economical to spray the commercial orchard annually for blight control but prune out badly infected material after harvest.
Harvesting has been by hand as most of the trees were assessed as part of various trials. We have tried nets and find them to be very successful at providing an easy harvest and clean nuts. They are very expensive and uneconomical for larger plantings. We plan to get a small vacuum harvester this season.
Nuts are sold in-shell to locals. We also supply some fresh handpicked nuts of Webb’s Prize Nut to a client who likes to eat his hazels fresh as they do in England.
A nut cracker is suitable for cracking hazels is to be set up in Whakatane this year and will allow us to supply kernels if required.
The hazel nursery is now our major business. As well as propagating the main commercial varieties, I have been running a simple breeding program for the last 10 years. The main aims of this program are: to breed a replacement for Whiteheart with resistance to blight and low suckering tendency; to breed new pollinators for Whiteheart; and to breed commercial varieties with low chill requirements.
Seedlings are grown in the nursery for 3 years, by which time those susceptible to blight (usually at least 50% of the seedlings) are dead or are removed. Those surviving are planted in hedges along the farm fencelines. Those that crop early, are healthy, and have good quality nuts are then propagated and will be planted in the orchard to be further assessed.
We are already assessing a number of selections that may be suitable as pollinators for Whiteheart.
Most of our remaining flat land may be required for the nursery so future plantings will be restricted to experimental plots. We are bulking up supplies of Gisborne to plant a trial in 2005 comparing Gisborne with Whiteheart. Gisborne has cropped well here, has very few suckers, and the kernels blanch 100%. Crackout is lower than Whiteheart but yield appears to be significantly higher so we should yield more kernel per hectare with Gisborne. Any large trees that remain unsold in the nursery at the end of each season are planted out in hedgerows on the farm.