Walnut Blogletter 29 – April 2017
This blogletter is a quick appeal for information from you lot. We have just had the absolutely worst season weather-wise that any of us imagined. A problem, yes. But it is also a once in a lifetime opportunity to learn about growing these walnut things. So please get on your computer and give us a quick description of how this season has treated you. If everyone does it we will learn answers to questions none of us ever thought of. So, if you are reading this, give us a quick note of how this season treated you. It only has to be a few lines.
To get you started here are a couple of email exchanges. Kate Carter has lost a big part of her crop, can you help her? Valda Muller in Otago was confronted with all her crop on the ground in one day, on a soggy boggy ground. Is this the weak link in machine harvesting? [Read more…] about Walnut Blogletter 29 – April 2017
Walnut Blogletter 28 – March 2017
Covered in this blogletter is our continuing battle with Phytophthora, and the latest results in our search for better walnut varieties. Plus I have thrown in a few notes on random walnut topics spotted on the internet.
A follow up on our stumping experiment…
In the May 2012 blogletter I described an experiment of ‘stumping’ some 4 year old trees that had been knocked over by a slip. That winter I cut off the tree as close to the stump as I could get and a year later had a profuse coppice of shoots about a metre high. Each summer, to avoid excessive bleeding, I reduced the number of shoots, till I finally got it back to one shoot last year; 4 years after the initial stumping. I think it was a success in terms of tree form, and the growth is not far behind the neighbouring row of trees that was not touched by the slip; well worth doing. [Read more…] about Walnut Blogletter 28 – March 2017
Last July I introduced the blogletter with this paragraph.
With the huge increase in walnut plantings around the world, especially in China, we need to focus on what advantages we can exploit for walnuts grown in New Zealand. Massive planting has also been happening in countries around the Mediterranean as well as non-traditional places like Australia and Chile. Even in USA the big increase in walnut area is meeting headwinds now their exports to China are finding resistance. We need, and will need even more in the future, to exploit our competitive advantages. In this regard I view any differences in approach, a strength.
So whatever you are doing with your walnuts, let us hear about it, so we can all learn.
To which Valda Muller replied;…
We sell all of our walnuts direct to customer – either farmers market or mail order. The majority would be in halves and pieces. We tend to be sold out really quickly so at this stage I feel that we still have space to grow our market
The May Walnut Industry Group (WIG) newsletter raised some issues in my mind.
It seems that we were not the only people to have a challenging walnut harvest with prolonged autumn rains. This report was in April this year. Intense rainfall has had a major impact on Chile’s walnut production, in particular the late season Chandler variety, says the grower and exporter association Chilenut. You can see the full article here.
The report went on to detail how the rain not only caused significant loss of production, but quality downgrade for part of the harvested crop too. They also said that further rain was forecast which was going to cause problems in harvesting the last of the crop. So, reading between the lines it appears the rain must have disrupted mechanized harvesting, and meant nuts that were collected were left out in the rain too long.
Nelson Hubber, chairman of Walnut Industry Group (WIG) also said, ” Like many in Canterbury this year Meyric produced the best and biggest crop at our place. Rex let us down with a very small crop due to a November frost. Only a fraction of the amount of last year.
Up in the Bay of Plenty production was good, but Rex only had a light crop even though we did not have the November frost. All these observations highlight a classic growers dilemma. How many varieties do I grow?
- There are pluses and minuses.
- A range of varieties with a spread of pollination and harvest times gives longer to collect the crop, with less pressure on facilities and machinery, and of course, insurance against those unusual weather events.
- But the flip side is that only having limited selections enables the grower to fine tune machinery to nut sizes and shapes.
- In theory one would hope that the main variety planted is the most productive, and any others added to the mix will lower average yield and/or quality.
The problem with all of this is that a walnut tree is productive for decades, cannot be topworked in New Zealand, and new varieties are coming on the scene all the time. How did you decide what varieties to grow at your place?
California’s 2015 walnut acreage is estimated at 365,000 acres, up 12 percent from 2013. Of the total acreage, 300,000 were bearing and 65,000 were non-bearing.
Of the walnut acreage reported, Chandler continues as the leading1 variety with 104,450 bearing acres, followed by Hartley with 33,002 bearing acres. Chandler also accounted for 67 percent of the non-bearing acreage.
Chandler was released in 1979. That was quite a while ago. Hartley has been around from 1915.
Combined sales of walnut trees to California growers were 18,021 acres for the 2015 crop year. The Chandler variety accounted for the largest percentage of new plantings at 75.8 percent. The Tulare variety came in second at 14.0 percent, followed by the Howard variety at 6.0 percent.
Tulare and Howard were also released in 1979. So does the release of Ivanhoe in 2010, and now the release of Durham this year cause a change in varieties planted?
Here in New Zealand, WIG imported Tulare and Howard, but not Chandler. That was probably a wise move as our climate is quite different. The third variety that WIG imported was Lara, a new French variety, released in the 1980’s. Trials on our place show Lara cropping better than Tulare. But is it more productive than Shannon (1335) which was the best producer at the Masterton trial?
In the 1980’s California produced 80% of the world walnut crop. Production had gone up from about 2 tonnes per hectare (t/ha) in 1970 to 3.5 t/ha in 1979. The area in bearing had only increased by 5% in that time, but management had become more professional, with better machinery and varieties. The most promising selection, Serr, released in 1968, turned out to be a fizzer with very variable cropping caused by what turned out to be Pistillate Flower Abscission. (The flowers don’t set.) Consequently growers were very cautious with new varieties, sticking to ones that they knew; Ashley, Payne, Vina, Hartley and Franquette.
But in 1983, that all changed when California suffered a season like the Chileans have just had. All their beloved ‘proven’ varieties except Hartley bombed out. Only Chandler and Howard, which had just been released, produced marketable kernel; and everybody wanted them. And now they are averaging a yield of nearly 5 t/ha.
So what has this got to do with us growing walnuts in New Zealand?
Christchurch growers have settled on Meyric and Rex, and have not planted the heavier bearing Shannon extensively. In spite of Shannon having beautiful nuts, Rex has been planted because of its kernel quality. It is going to take a much better variety for people to shift. Lara might be a contender. It does have the kernel quality.
North Island growers, with a wetter climate, are comfortable with Wilson Wonder. Some are starting to plant Shannon and Roadside 12. Will Lara be an option?
How did you decide on what walnut trees to plant? Let us have your stories. It will help those who are still planting, or about to plant. For my part, I am still putting in trees, and it is quite difficult to decide what to propagate. This year I have planted Shannon, Roadside 12, and interesting seedlings from the breeding programme.
Incompletely formed walnut shells – Cause?
Trudi and Basil Meyer [Located in Darfield, Canterbury] sent me this email;
I thought I [would] send you some photos of some of our walnut shells. They seem not to have totally formed and look disfigured.
It predominantly happens to Tehama and Meyrik Walnuts. And we had quite a lot of it this year. We are looking for some ideas how to prevent it in the future.
Let’s start with the basics; how a walnut develops on the tree. My understanding is that we start with the flower in October/November which is not much more than an ovum inside a miniature husk. As the nutlet develops it is mostly growth of the husk with a rudimentary beginnings of the shell inside. The shell is nearly full size mid December, and only then starts to harden up, (lignify). Once the shell is fully developed, the kernel inside starts to develop and fill out.
From your photos, it looks as though something happened to your trees when the shell was forming that meant there were inadequate recourses for the tree to look after itself and form shells properly. I only know of two limitations to shell development in NZ; nutrient deficiency (It typically happens with boron for Franquette at our place.) or drought. Did you have a bad drought at Christmas time?
I googled it and found a Chinese article that looked at the problem and reported that it was correlated to variety and also to sunlight intensity. Presumably the nuts were cooking on the tree, which can be a problem in California too.
You also might like to look at this article from the University of California. ‘Drought Strategies for California Walnut Production‘
Are we getting close? Maybe we can work this out together? Did any other bloggers suffer similar shell deformation?
While we are on the subject of how walnuts form on the tree; an article I found on the net. (My bold highlighting);…
PRELIMINARY ELEMENTS OF REFLECTION ON THE POSSIBLE PRESENCE OF VITREOUS OR TRANSLUCENT WALNUT KERNELS
In France, walnut distributors are often disturbed by the presence of a proportion of « vitreous » walnut kernels which appear vitreous after drying and at the beginning of the breaking operation. The Creysse Experimental Station has undertaken a study in 1995 to try to understand this phenomena. Observations were targeted at the formation of the nut (type of soil / fertiliser / irrigation), before- and after-harvest parameters (date of harvest / maturity / period spent on ground / time before drying / drying conditions). The analyses, which were carried out on dry nuts (November) and after six months of conservation, were based on the general aspect of the kernels (calibre, colour, etc.), as well as biochemical analyses on the walnut kernels. The early results show a relation to : – Irrigation : a significant difference between shortened or prolonged irrigation on the percentage of glassy walnut kernels following harvest and conservation, – Harvest date : the walnuts harvested by vibration are more vitreous than those which fell naturally; there is a higher percentage of vitreous walnut kernels in those harvested in the husk, – Period spent on the ground : unlike other parameters (particularly colour), the percentage of vitreous walnut kernels tends to decrease with the increase of time spent on the ground. Hypothetically, it can be suggested that this phenomena is either connected to a change in the water content of nuts, with this content decreasing over time as the nut dries, or that the percentage of vitreous kernels is lower when the walnut kernels are coloured, or that these two parameters coincide. – Drying conditions: Walnuts dried at a lower temperature and at for a longer time have a higher « vitreous rate ». « Vitreous walnuts » do not seem to present any anomalies at the level of general biochemical parameters.
I thought this was a cautionary experiment at this early stage of our industry’s development. I am always getting complaints from my customers about the walnuts from the States that are translucent,(vitreous) in appearance. We have never noticed more than the very occasional translucent kernel, presumably because our primitive operation allows the nuts to mature and drop naturally, whereupon we pick them up as quick as we can. But what would happen if we shook them from the trees with tree shakers? Do any of you shake your trees? And what is your experience with translucent kernels? The experiment also hinted at some connection with irrigation practice. What is the experience of those of you who irrigate? The connection with irrigation implies to me that translucence can also occur when there is inadequate moisture to properly develop the kernel late in the growing season, even if the shell has formed properly.
If you google ‘translucent walnuts’ you come across Cracker-of-a-Nut website cautioning suppliers about drying their nuts properly. They describe rubbery incompletely dried kernel as translucent. But I would see that as quite different from the greasy kernels that have been shaken from the tree before they have formed properly. Would you make this distinction?
Trudi is one of the few who have gone on the walnut blog on Facebook. Maybe it is time to revisit this. If I lost control of the Walnut Action Group blogging and it became Facebook based, that would suit me just fine! Just log onto Facebook and search for NZTCA Walnut Action Group.
All the best
nick nelson parker
Reproductions. If you would like to reproduce any of nick’s blogletters, you must include the source of your quote and the following email address firstname.lastname@example.org
Some of the ideas expressed by Bill Rae, 28-Feb-2016. Compiled by Don Harwood.
- Remove excess growth to allow light into the tree and onto fruiting buds
- Stimulate new growth. Heavy pruning stimulates lots of new growth but less fruit production.
- Shape the tree, pyramid or open vase shape typically. Vase has only one layer of branches extending from the stem.
- To limit tree height and width
- Remove diseased, dead and deformed wood
- If summer pruning is done for stone fruit, winter pruning is normally not required (unlike apples).
Guidelines for Growing Hazelnuts in New Zealand
You’ve heard of that ‘old chestnut’ – perhaps we have defined it here:
The Chestnut industry in New Zealand has been arduously nutted out many times over; but it always seems to relegate itself into the ‘nearly made it’ chest.
This time – 2013 – there still remain international markets pleading for product.
A leading tree propagator of great experience holds a bud grafting workshop featuring chestnuts.
He has supplied thousands of trees over decades for this elusive industry –
Where is this chestnut industry that has swallowed up so much effort?
While we wait for answers from the many people attempting a rebirth, let us see what we can find from the archival chest of dreams about this unfulfilled crop.
Below is a Basic Crop Fact Sheet from 1997, abridged only to remove references to authorities believed to be no longer with us.
We intended to follow up with coverage of recent progress outlined at the field day (embargoed), much of which is inspiring. (We never did find a reliable method for returning to topic after the 3-month hold, but thankfully those requirements have eased.)
Meanwhile, a great export market goes unsatisfied – which we are well placed to supply.
See the Chestnut Cart in the Nut Crops Summary
Written by Eric Cairnes, NZTCA – February 2000
So you’ve bought or are thinking of buying a rural block and perhaps earning some retirement income from growing something, preferably something you yourself like eating. What about nuts? They are high value, store well, are eary to transport, lend themselves to niche marketing and can be managed on a fairly small scale.
Remember the in shell nuts you indulged in over Christmas. If you chose well, you found some excellent quality locally grown walnuts or hazels. Most of us however, bought mixed packs of nuts imported from around the world. They were stale and rancid and we wondered why we had bought them. Well perhaps its too cold for Brazil nuts here and peanuts are pretty marginal, but, almond, walnut, hazel, macadamia, pinenuts and chestnuts do well. And how much better they would have tasted fresh.
The New Zealand Trees Crops Association, which has branches in most areas of the country, can help you get started, and most importantly, can put you in contact with other growers around NZ. Information is willingly shared at field days and evening meetings and through fact sheets, because we recognise that this is the best way to learn more ourselves.
From time to time there are specialist nut seminars held, and the annual conferences (this year at Lincoln over Easter Weekend) nearly always feature field events and seminars given by experts on nuts.
So if you are serious about a commercial nut venture, you should do your homework. Check out the world scene for indication as to potential. (Get yearbook data and search the Internet). Monitor trends in world prices, trends in planting and disease. Does NZ offer a strategic advantage (eg. season, climate, disease, access to markets etc)? What is the size of the local (ethnic) market? What are the costs of growing and harvesting/processing the crop? What supporting infrastructure is there to assist you? Membership of NZTCA makes it easier to find answers for these and many other questions.
Decide how to market you crop. Will you drop it on the local auction system, and accept commodity prices, or develop niche outlets for processed products and control the situation better.
In a general sense, the marketing aspect is the biggest hurdle for most small scale industries. In NZTCA, many of us are green fingered growers, and not strong on the presentation/marketing end. However, there are also many market success stories for niche products.
A new product in NZ such as gevuina nuts, may have difficulty establishing market demand unless there is sufficient supply. Wholesalers or large retailers may not want to invest in promoting or stocking a product line unless quality and supply is secure. Thus, even for products where there is established demand, but no local supply (eg pine nuts and pistachio), there is a ‘critical mass of product’ required to develop the market. This amount is quite likely more than one or several growers could supply, so don’t try to capture the market on your own. If you are keen on exporting, the amount of product to do business with may be orders of magnitude greater than would be necessary for domestic markets. Our advice is to cooperate with other growers to develop the infrastructure and markets.
Thus one of the strategies of the newly formed Gevuina Action Group is to get as many trees as possible planted as soon as possible in order to be able to “launch the product”. Quite deliberately, they are focussing on a few selections into order to standardise the product. Naturally there are risks involved with new crops if the best selections are not yet known and market demand is uncertain.
In the case of macadamias, walnuts, chestnuts, and hazels, there is now an established demand for local produce (or for export) and some established infrastructure to harvest, process and market the produce. The NZ Hazel industry is still very small, and gevuina, pistachio, almond, pecan, and pine nut are yet to gain ‘critical mass’ but gate sales and specialist retailers would still be interested in spot market sales.
The history of serious nut growing in NZ is quite recent and began with the foundation of the New Zealand Tree Crops association, 25 years ago. Some of our early researchers were also on the staff at DSIR or MAF and no doubt this assisted with the professional approach and early successes. A key trial area for nuts was the Crop research block at Lincoln and the cooperative venture with the then DSIR was a major success story. Some of these trials continue in the grounds of Lincoln University under the auspices of Dr David McNeil, a Research and Development Coordinator for NZTCA.
Before the formation of NZTCA, no one had done any systematic selection or breeding of nut trees suitable for NZ conditions. We weren’t even of the limitations of our climate. How then to develop a nut industry? The quickest way was not to spend 15 years breeding new varieties but to see how existing material would perform. The opinion was that NZ conditions were sufficiently different to other major nut producing countries, that imported varieties may not be any better than some selections already growing and adapted to NZ.
So in order to get the industries started, NZTCA held nut competitions to identify the best walnuts, chestnuts and hazels. The best of these were then propagated and put into trial plantings and compared with the best overseas varieties.
In the case of walnuts, some local selections have done extremely well and four of these (Rex, Meyric, Dublin’s Glory and Stan) were given variety names in 1998.
Some of our local hazel selections (eg Whiteheart) also compare well against Italian and American varieties.
In the case of chestnut, due to the prevalence of chestnut blight in most other countries, there was reluctance to import any new overseas material. Some did eventually get imported, but our local selections still form the bulk of the plantings.
With the founding of NZTCA, it still took 15 – 20 years of development to get walnuts, chestnuts and hazels to an industry size.
The nut crop summary below – Walnut – Chestnut – see also Nut Crop Guides may help you decide whether your favourite nut can be grown on your patch.
Species: Juglans regia commonly known as European, English or Persian walnut.
|Recommended Varieties||Numerous seedling and grafted selections available. It is important to match the orchard site with the right variety. Research is still continuing to select the best varieties for North Is conditions.|
|Climate||Rain or high humidity during spring to late summer increases the incidence of blight. Some varieties are more susceptible to blight than others. Dry east coast climates are preferred.
The leaves and flowers are damaged by unseasonal frosts. Areas subject to frost after mid October may benefit from late leafing varieties.
|Soil||Critical. Must be free draining down to 2 metres. Fertile soils of moderately high pH are required. Nutrients need to be well balanced.|
|Markets||Present local consumption far exceeds local supply and quality NZ kernel is readily sold. Said to one of the few commodity products which has maintained its value over the years.
The (heart) timber is amongst the most valuable wood there is, provided it is well grown and trees of large size. Walnut burr is particularly sort after. Heart content varies greatly.
|Harvesting||The nuts fall to the ground and must be harvested within a day to avoid deterioration. Various machines (vacuum and hedgehogs) available to pick up nuts. In dry climates, daily collection is less critical.|
|Post-Harvest||Nuts should be cleaned by water blasting and dried promptly. They will go mouldy if kept damp too long or bagged before internal moisture content is low enough. For home use, air drying on racks is adequate. Assisted drying is required commercially.|
|Orchard layout||Grafted trees are recommended for smaller orchards or where uniform nut quality is critical. Certain seedling lines come remarkably true to the parent.
In humid climates, timber may be the preferred objective. Where timber production is required, initial spacings should be 4 x 5 metres. Half of these should be thinned out in stages.
Where nuts only are required, use grafted trees at a maximum of 10 x 10 metres. Having more than one variety will assist with pollination.
|Orchard Management||Fertiliser is required. Mowing or spraying under the trees enables easy nut collection. Roots stocks can be J. regia or the hybrid “paradox” for well drained soils. J. nigra is preferred for wetter soils.|
|Pests and diseases||Apart from blight and root rots in poorly drained soils, other diseases are only of nuisance value. Blight can be controlled with copper sprays. No other compounds are yet registered for use.
Puriri moth can cause damage to young trees by ringbarking. Walnuts are palatable to horses and sometimes to possums.
|Shelter and Irrigation||Shelter is important, even in mild situations. Wind slows the growth down and cools the microclimate. Irrigation could be useful for very dry areas, especially during establishment. Don’t over water.|
|Payback Period||Grafted trees can start bearing after a year but an economic crop will not be achieved until at least 8 years under ideal conditions. Cropping is directly related to tree growth (and variety). The slower the growth, the longer the wait for nuts. As seedlings are generally more vigorous, they may be quicker to bear nuts|
Got to the Walnut pages
Species or hybrids between Castanea sativa, C. mollisima and C. crenata (Spanish, Chinese and Japanese)
|Recommended Varieties||1002, 1005, 1015, Disk II, Mayrick King, Mayrick Queen|
|Climate||Not fussy, as long as they are clear of salt spray|
|Soil||Critical. Must be free draining down to 2 metres. Soil fertility not usually a problem.|
|Markets||Nuts mostly exported and local market is fully supplied, but expanding. Overseas markets pay highest prices for processing quality nuts, but this has not yet happened here. A recent development is the production of chestnut meal in NZ for the food industry. Chestnut timber is also highly sought after overseas. Timber from C sativa is naturally ground durable.|
|Harvesting||The nuts fall to the ground and must be harvested within a day to avoid deterioration. Prickly burrs present a problem. Various machines (vacuum and hedgehogs) available to pick up nuts|
|Post-Harvest||Chestnuts are starchy and taste rather like kumara. They can be dried for use like flour. Usually stored moist in cool stores. Processing into meal involves cooking and pressing|
|Orchard layout||Minimum spacing is 6×6 m. Some growers are allowing much more room. Chestnuts must not be thinned by cutting trees down. Dying roots would cause fungal infections in the remaining trees. (Therefore dig trees out). Most growers are planting 3 varieties. Harvest has to be by variety. Nut quality is modified by the pollinator.|
|Orchard Management||Very little is required except for mowing or spraying under the trees to enable easy nut collection.|
|Pests and diseases||Puriri moth, grass grub beetles, cicadas and opossums can cause serious damage on young trees. Very palatable to livestock. The fungus phomopsis affects storage of the nuts. At present no sprays are registered for use on chestnuts.|
|Shelter and Irrigation||Shelter is helpful in exposed situations. Irrigation can make establishment easier and increase crops. Both are important in severe climates.|
|Payback period||Grafted trees will start to bear after a year and should be giving an economic return by age 4. The pure Japanese varieties take a year or two longer.|
Wednesday, 27 August 2003 – Updated: 2015-02-20