The almond tree, Prunus dulcis, is a deciduous tree in the family Rosaceae that is grown for its edible seeds (nuts). The tree has brown or gray bark and either an erect or weeping growth habit, depending on the variety. The trunk can reach 30 cm (12 in) in diameter.
Almond leaves are 7.5–13 cm (3–5 in) long with a serrated edge and grow alternately on the branches. The tree produces white to pale pink flowers and hairy green fruits that are oblong in shape. The fruit is a drupe, containing a single seed. The seed is protected by a hard brown shell.
At maturity, the flesh of the fruit becomes leathery and splits to reveal the nut inside. Nuts generally measure 3.5 to 6 cm (1.4–2.4 in) in length. Almond trees can reach heights between 4 and 10 m (13 and 33 ft) and have a commercial lifespan of between 30 and 40 years.
Almond may be referred to by variety and this includes bitter almond. Almond nuts are generally long and may also be referred to as sweet or bitter almonds, depending on the variety. They originate from wild species found in Central and Southwest Asia.
Crop Details
Scientific name: Prunus dulcis
Other Common Names: Almendras (Spanish), amandes (French), mandorle (Italian), Mandeln (German), badaam (Indian), لوز (lawz in Arabic) 杏仁 (xìngrén in Mandarin Chinese) and アーモンド (āmondo in Japanese)
The almond nut is eaten raw or processed into butter, flour, extract, oil, paste, syrup, and milk.
Almond oil is used as a flavoring agent in baked goods, perfumery and medicines. Sweet almond oil is used for cosmetic creams and lotions.
The hard shells of almonds can serve various functions, such as abrasives and sustainable materials.
Basic requirements
Almond grows best in Mediterranean climates with warm, dry summers and mild, wet winters. The optimal temperature for their growth is between 15 and 30°C (60–85°F) and the tree buds have a chilling requirement of between 300 and 600 hours below 7.2°C (45°F) to break dormancy. Almond trees will grow best when planted in deep, well-draining loam, although they can withstand drought and grow in poor soils. The trees benefit from being planted in areas sheltered from frost and wind, as trees bloom early and can therefore be susceptible to damage from late frosts. Trees will generally bear nuts after 3 to 4 years, with the nut crop developing after blossoming in the fall.
Propagation
Almond trees are most commonly propagated by budding. Dormant wood is collected in winter, when the trees are dormant and stored until spring. T-budding is usually carried out in spring and involves joining a bud from one variety to the rootstock of another. The bud is taken from a parent with desirable characteristics and grows to produce a new tree. Trees may also be propagated by grafting. Cuttings are taken from trees during dormancy and grafted to a suitable rootstock in the spring.
Planting
Once trees have been acquired from a nursery, it is important to plant them as soon as possible and keep the roots moist in the meantime. Almond trees should be planted by digging a hole just deep enough to accommodate the root ball. The tree should be planted by carefully backfilling the hole around the tree after it has been properly positioned. The planting depth should not exceed the height of the graft union. The soil around the newly planted tree should then be tamped and watered deeply but not excessively. If planting multiple trees, then they should be spaced in rows 6–7 m (20–23 ft) apart, with 5–6 m (16–23 ft) between each tree.
Pruning
Almond trees should be pruned in the first year and every subsequent year to help thin the canopy and prevent disease. The first pruning is critical to establishing the canopy shape. Three limbs should be selected to form the basis of the tree's canopy and all others removed, including any growth below the lowest limb. In the second year, two scaffolds (lateral branches that grow to form a Y with the primary limbs) should be selected and the rest removed. Aim for the remaining scaffolds to be evenly spaced around the canopy.
General care and maintenance
Almond trees will benefit from a layer of mulch around the base to prevent the growth of weeds and conserve soil moisture. Mulch should be spread around the tree in a 1 m (3 ft) radius. Leave a gap between the mulch and the trunk to prevent it from rotting. In addition, an application of fertilizer should be made once in the spring before any new growth and again in the fall.
Harvesting
Almonds are typically harvested in the dry season, usually between August and October. The process begins with shaking the almond trees using mechanical tree shakers or hitting them with a pole, causing the mature almonds to fall to the ground. Once on the orchard floor, the fallen almonds are then collected and put in storage bins or trailers, which will later be transported for processing.
CABI Crop Protection Compendium. (2010). Prunus dulcis datasheet. [Accessed 05 November 14]. Paid subscription required
Doll, D., DeBuse, C. & Beede, B. (2011). Almond Pruning and Training. UC Davis Fruit and Nut Research and Information. Available at: http://fruitsandnuts.ucdavis.edu/almondpages/AlmondPruningTraining/. [Accessed 05 November 14]. Free to access
Teviotdale, B. L., Michailides, T. J. & Pscheidt, J. W. (Eds) (2002). Compendium of Nut Crop Diseases in Temperate Zones. American Phytopathological Society Press. Available at: http://www.apsnet.org/apsstore/shopapspress/Pages/42848.aspx. Available for purchase from APS
Press Webb, D.A. (1998). Prunus dulcis (Mill.).Purdue University Center for New Crops and Plant Products. Available at: http://www.hort.purdue.edu/newcrop/duke_energy/Prunus_dulcis.html. [Accessed 05 November 14]. Free to access
Last updated July 14th 2023 by Eluby Kawelama based on knowledge from CGIAR, CABI and FAO. Discussion with Jan Kreuze of CIP
Chlorotic leaf margins; necrosis of leaf margins beginning toward tip of leaf and spreading to base; patches of necrotic tissue with chlorotic margin
Bacterium
More of tree will be affected each year; bacterium can infect rye, blackberry and nettle and if these plants are nearby they may act as reservoir; transmitted by leafhoppers and spittle bugs
If discovered early (while disease affects only one branch) disease can be removed by pruning primary scaffold 5 to 10 ft below symptoms; older infections may require the tree to be removed and replaced