Written by Anna-Marie Barnes This article was first published in Lifestyle Block
This month, we’re going nuts for almonds. Although this versatile member of the Rosaceae family does not provide a crop to harvest in September, it is a cheerful harbinger of spring, among the first of the fruiting trees to flower (somewhat profusely) in late winter and early spring. As such, I think it deserves an early spot in the productive-crops calendar and a place in your garden.
Nuts are increasingly in the nutritional spotlight, and consumer demand is high, in accordance with the current trend towards plant-based eating. They are no longer demonised as a high-fat indulgence, but touted as beneficial inclusions to a healthy diet. Perhaps of most interest to the home gardener is that with a little room to move, a moderate climate and some careful planning, backyard nut production can be well within your grasp. Almonds are an excellent starting point, as they can be grown successfully in climates where their cousin, the peach, also thrives. Dwarf varieties are available, which brings them within the scope of those on smaller sections.
Many people, myself included, may have stumbled across almond trees inadvertently, noticing the peach or nectarine-like foliage in spring and summer and then wondering why the small, misshapen fuzzy green things fail to develop into succulent, rotund fruit further down the track. At the age of ten or so, I was visiting a property with friends and we kids happened upon an almond tree in the garden. It must have been late summer or early autumn, and we crowded around the tree, where some of the green fuzzies had already dropped to the ground. Our initial guess was a peach of course, but after a great deal of poking and prodding (and probably some stomping) plus a little adult intervention and cross-referencing one of those fancy net bags of in-shell nuts that used to float around at Christmas, we learned that the tree was indeed an almond.
Almonds: a short family history
The sweet almond, Prunus dulcis (syn. P. amygdalus) and its relatives the peach, nectarine, apricot, cherry and plum, originate from the temperate regions of the Northern Hemisphere, specifically Western Asia, which encompasses a large chunk of the Middle East; Turkey, Cyprus, the Arabian Peninsula, the Sinai Peninsula, Iran, Iraq and surrounds. Almonds later dispersed to Eastern Asia, Northern Africa, Southern Europe and Northern America – cultivation was evident in China from the 10th century BC and in Greece from the 5th century BC. Almonds thrive in Mediterranean climates, hence the key almond-producing countries were traditionally from this region; however the state of California in the United States now produces 80% of the world’s almond crop, which at a value of US$5.2 billion per annum makes them the state’s most valuable export crop. As an aside, if you subscribe to the audiobook provider Audible through Amazon, I recommend you take a listen to Marc Fennell’s Nut Jobs: Cracking California’s Strangest $10 Million Dollar Heist for an insight into just how much these crops are worth on a worldwide scale. Australia is the Southern Hemisphere’s largest producer, with New Zealand having a few relatively small, niche producers growing for the domestic market.
An important distinction should be made at this point: almond varieties are split into bitter (P. amara) and sweet (P. dulcis) species – the former are not so useful in the home garden, and care must be taken as their kernels contain cyanogenic glycosides and an enzyme, emulsin. Cyanogenic glycosides are compounds which when broken down in the presence of emulsin and water produce high levels of hydrogen cyanide, a deadly poison. With bitter almonds containing between four and nine milligrams of hydrogen cyanide per nut, 5-10 bitter almonds could kill a child and 50 could be fatal for an adult. With correct commercial processing, bitter almonds yield almond flavouring extracts and are used in some baked products, but are otherwise best bypassed. The bitterness in almonds is carried on a single gene, which is itself recessive, and it is thought that the distinction between sweet and bitter types and the subsequent selection of sweeter nuts from the wild signalled the beginning of the domestication of this species. P. amara nuts are always bitter; P. dulcis nuts are predominantly sweet but some individual P. dulcis trees may produce nuts with a slightly more bitter flavour than others.
Sweet almonds are categorised further by their shell characteristics – falling into either paper-shell (cultivars which have a pithy, crumbly shell that can be rubbed away by hand), soft-shell (cultivars which have a firmer shell but which can be broken using pressure from your hands or a domestic nutcracker) and hard-shell (cultivars where the shell cannot be broken by hand and always require cracking mechanically to extract the kernels).
Suitable climates and growing conditions
As previously mentioned, almonds will generally do well in New Zealand wherever peaches can be grown successfully. They are cold-hardy when dormant, but being amongst the early-flowering Prunus species, require less chilling hours than other stonefruit to set fruit (in the region of 200-700 hours below 7°C). It is important that temperatures do not drop below -1 to -2°C during the full bloom phase, but unopened ‘pink’ buds can withstand -4 to -7°C. Keeping in mind the preference for a Mediterranean climate, Hawke’s Bay, Nelson/Marlborough and sheltered regions in Canterbury and Otago will offer the most suitable conditions, with the lower-humidity climate of the South Island offering additional benefits. High humidity and rain during the growing and harvest seasons are also unfavourable, as they may lead to the development of fungal and bacterial diseases, affecting kernel development and maturation. Commercial crops have been grown as far south as Blenheim – the further south you go, the more consideration will be required around protecting vulnerable blossom from spring frosts.
Almonds are medium-sized deciduous trees, averaging four to ten metres in height at maturity. Some control over height and stature is achieved by selection of appropriate rootstocks. Trees can live for up to 70 years, and have an upright growth habit in the juvenile phase, shifting to a spreading structure in later years. In New Zealand, flowering commences in late July and continues into September – mild weather at flowering is favourable for ensuring good pollination as honeybees and bumblebees carry out the majority of this. The flowers are white to pinkish in colour. There are a small number of self-fertile cultivars available but most are self-sterile and will require a polliniser – therefore it is best to plant a few varieties in a block. Peaches and almonds are reportedly able to pollinate each other, so if you have a mixed orchard, plant your almonds in the vicinity of peaches if you have them. Care must also be taken not to grow sweet almonds near bitter almonds, as crossing the two varieties will result in bitter nuts being produced. The fruit is borne on a mixture of one year old wood and older two to three year old spurs. Time from flowering to harvest is seven to eight months (nuts mature and fall March-April). You can expect a crop in your tree’s third or fourth season, and full production at around six to eight years of age.
Commercial almonds are budded or grafted onto rootstocks, usually peaches such as Golden Queen (which confer some resistance to crown gall and nematodes), Marianna plum (which has a semi-dwarfing effect) or almond/peach hybrids (which convey vigour and result in deep root systems). You might like to bear these characteristics and your site conditions in mind when choosing your trees.
Site selection and planting
Choose a sunny but sheltered location for your almond trees – if your site is frost-prone, planting on a slope can help. Planting in a sheltered position will aid pollination, which requires warm, settled conditions to ensure a successful crop. Almonds are fairly adaptable and will tolerate a range of soil types, but well-drained, fertile, light to medium types are best – almonds can cope with heavier soils but they must be well-drained as the trees do not tolerate waterlogging. Trees are best planted in the late winter to early spring period – be warned, they can be slow to establish and may remain dormant for a season before starting to grow. Allow at least three metres between trees, within and between rows – if you have plenty of space, this can be increased to six or seven metres, and don’t forget to include a polliniser variety somewhere in the vicinity – one for every two to four trees is ideal.
Culture and care
Almonds are deep-rooted trees, so have a degree of drought tolerance. That said, if your annual rainfall is below 500 mm, supplementary irrigation may be required at key times, particularly in the initial fruit development stages and again in the final stages of ripening before harvest. Avoid overwatering, especially in the spring during pollination and during the main growth phase in summer to stave off fungal disease.
In terms of fertiliser requirements, almonds respond well to nitrogen applications and these can improve tree growth and subsequent yields. One to two kilograms per tree (depending on age and size) of a general NPK orchard fertiliser applied in spring should be sufficient.
Almonds require less pruning than their cousin the peach, which is good news if you like to keep a low-maintenance garden. The cuts made tend to be larger but fewer. An open-centre or vase shape is the most suitable – at the end of the first growing season, choose three to four good leaders and head them back. At the end of the second growing season, allow two to three secondary branches to remain on each of the leaders but don’t head them back. After this, all that is required is thinning out of weak material and any branches that cross over each other. Aim to encourage the production of one year old lateral wood and spurs on two to three year old wood and their subsequent replacements to maximise fruiting. Summer pruning can help with disease prevention by removing excess foliage, keeping the canopy dry and open. Remember to only prune on dry days and seal all cuts with pruning paint to prevent disease ingress.
Pests, diseases and what to do about them
The main disease issue for almonds is bacterial blast, caused by Pseudomonas syringae pv. persicae which causes cankers, bud dieback and patches of resin-like gum (gummosis or weeping sap) to form on trunks and the nut husks. Some cultivars do seem to have a level of resistance, and if the area affected is localised and on the tree’s outer branches, it can be treated by pruning off the diseased wood and immediately sealing the cut with pruning paint or paste. Burn or dispose of infected wood, do not compost or mulch it. Fungal diseases which also affect other stone fruit can be an issue, namely brown rot, leaf curl and silverleaf.
A copper spray, applied at leaf fall, and/or Bordeaux mixture as a winter clean-up spray when the trees are dormant should help alleviate these diseases. Maintaining an open canopy structure and summer pruning will help with fungal diseases by allowing good airflow though the canopy and exposing the foliage to light.
The green peach aphid, Myzus persicae, can cause feeding damage and dieback, especially on young tender shoots. Other insect pests of note are leafroller caterpillars and scale insects. Depending on your personal preferences, you can opt for a neem, vegetable or mineral-oil based spray to control aphids and scale, and a product such as Yates Success Ultra for leafroller caterpillars.
Harvesting and processing
Almonds mature in late summer, and as the fruits ripen the peach-like exterior hull usually splits open, exposing the stony nut. You can either pick the nuts from the tree by hand, gather them from the ground if they drop, or shake them from the tree (machinery is employed for this step in commercial operations). If the green hull remains intact, it will need to be removed prior to drying. The nuts can be dried on trays or racks in the sun or other warm, well-ventilated conditions, shaking and turning them daily until you can hear the kernels rattling around inside the nuts and/or when cracked open, the kernel inside is no longer rubbery to the touch but crisp and dry. This may take up to six weeks, conditions dependent. Store the dried in-shell nuts in mesh onion bags in a vermin-free area prior to shelling. Cracked kernels should be placed in ziplock or cellophane bags and frozen for long-term storage.
Varieties: My top picks
The Nelson Branch of the New Zealand Tree Crops Association conducted research into suitable almond cultivars for the local climate, with plantings on several trial sites commencing in 2003 and continuing until 2010. General climatic conditions across the district are clear, sunny winters with occasional light frosts, dry summers, and annual rainfall of 800-900 mm.
Evaluations of the best-performing cultivars are summarised as follows, with additional information from contributing nurseries:
All-in-one (occasionally known as ‘Fatnut’) Vigorous upright growth, semi-dwarfing, healthy trees. Self-fertile. Crops when young, husk self-separates, medium-strength shell, high yielding with good flavour. Early flowering may be affected by frost in cooler areas. Lower chilling requirement.
403 Spreading growth form, healthy trees. Late flowering, crops consistently when young. Sweet-tasting soft-shelled nuts. Flowers over a long four week period, a good polliniser for Fabrin. Suits drier climates.
Garden Prince Has dense foliage which hangs on the tree into winter, hence has ornamental potential. A low-chill variety, suitable for northern regions. Self-fertile and with dwarf stature, so suitable for container culture. Soft shell, but in our experience not a prolific producer.
CY750 Vigorous, healthy trees which are not affected by gummosis. Paper-shell, low yielding but large nuts with good flavour.
Fabrin Vigorous growth and a consistent cropper once it reaches maturity. Nuts have a medium-soft shell and mild flavour. 403 is a suitable polliniser.
Monovale A versatile polliniser. Produces a large, early crop of very strongly-flavoured nuts in extremely thick, hard shells. If you like marzipan, you’ll like this almond. Consistent yields, and the hard shell means pests and diseases can’t get in. The kernels are smaller and flatter than the milder-tasting varieties. Self-fertile.
McCartney R3 Sizeable crops of good-quality, golden-coloured kernels, some doubles. Small, sweet nuts, medium-strength shells. The husk falls away cleanly, leaving the nuts hanging on the tree.
McCartney R6 As with R3, good crops of high-quality golden kernels. Small, fat, sweet nuts with medium to hard shells. Looks good in shell and out and cracks well.
At the time of writing, All-in-one, Garden Prince and Monovale are supplied to garden centres nationwide by Waimea Nurseries in Nelson. All-in-one, Monovale and CY750 are available from Southern Woods in Christchurch. River Terrace Nurseries in Brightwater (near Nelson) propagate the R-series (1-6) from material ex-Marlborough and currently have R4 in stock and can take orders for other numbers. Specialist nurseries may be able to supply the lesser-known cultivars.
What to do with your crop
I was intrigued to find that immature green almonds are consumed as a delicacy in the Middle East and other almond-growing regions – the whole fuzzy fruit is edible, but the developing shell region can be unpalatable, so most commonly the jelly-like embryonic nut is popped out of the immature hull and eaten, often dipped in salt or sugar first. They can also be pickled, to extend consumption of this delicacy past the short season of availability.
The almond comes into its own as an ingredient or flavouring for a host of baked goods and confections the world over – from the plain and everyday to specialties for holidays and celebrations – think almond croissants, Esterházy torte, nougat, croccante (the Italian version of almond brittle, fantastic biscotti and not forgetting the nut’s most famous sweet incarnation, marzipan.
Almond milk has had a turn as the alternative milk du jour, and the nut holds its own in savoury settings just as well – made into nut butter or roasted and salted as a simple snack, or taking a star turn in the almond-based gravies of Mughlai and pasanda-type Indian curries (the latter being one of my favourites). In Iran, almonds are used to prepare harire badam (almond milk cream), which is a nutritious, easy-to-eat food for young children, the elderly and those with sensitive stomachs.
It may take a few years to produce a crop large enough to create some of these more ambitious dishes, but before too long, you should have sufficient nuts to at least be the envy of your friends and neighbours!
This month I’m going to pass on a recipe that is a firm favourite in our family and uses almonds in two forms. I’ve adapted it from a recipe in a cookbook my Mum received for her 21st birthday, written by Marguerite Patten, doyenne of 1960s British cuisine. I’ve adapted it by converting it to metric quantities and upping the almond factor.
Apricot almond sponge
1 x ½ litre Agee jar of preserved apricots in syrup OR 2 x 400 g tins apricot halves OR 500 g fresh apricots (in season). 50 g whole natural or blanched almonds
125 g butter 125 g sugar, preferably caster 2 medium eggs Zest and juice of one lemon 125 g plain flour (can substitute a proprietary gluten-free flour blend such as Edmonds) 25 g ground almonds (¼ cup) 1 tsp baking powder
Preheat oven to 180°C
Place the fruit in a Pyrex dish – 20 cm square or 20-24 cm diameter works well for these quantities. If using bottled fruit, place it directly in the dish with all the syrup from the jar. If using canned fruit, drain one tin and discard the syrup, then place the drained fruit in the dish with the second can of undrained fruit. If using fresh apricots, halve and stone the fruit, place it in the dish with ¼ cup water and bake in the oven for 10-15 minutes until the fruit begins to soften, then remove and set aside while you prepare the sponge.
In a large bowl, cream the butter, sugar, lemon zest and juice. Place the flour, baking powder and ground almonds in another bowl and combine with a dry whisk. Beat the eggs into the creamed mixture alternately with spoonfuls of the flour/almond mixture to prevent it all curdling. Continue beating until light and fluffy.
Place half of the whole almonds on top of the fruit, spreading them out evenly across the dish. Dollop the sponge mixture on top, smoothing it out the best you can – any gaps will be filled as the sponge cooks and spreads. Place the rest of the whole almonds on top of the sponge…arrange them in a fancy pattern if you are that way inclined!
Bake for 35-45 minutes, until well risen and golden and a skewer inserted in the centre of the pudding comes out clean. Guaranteed to brighten the dullest of winter days and generate many recipe requests from your guests.
Anna-Marie Barnes is an active member of the New Zealand Tree Crops Association who endeavours to grow and preserve as much of her own fresh produce as possible. When the weather’s no good for gardening, she can usually be found inside working on a batch of homemade cheese or soap.
The New Zealand Tree Crops Association is a voluntary organisation promoting interest in useful trees, such as those producing fruit, nuts, timber, fuel, wood, stock fodder, bee forage and other productive crops. Find out more about the NZTCA here: https://treecrops.org.nz/