Almond (Prunus dulcis) is a tree native to the Middle East that’s prized and cultivated throughout the world for its edible nuts. The fruit of this species is called a drupe. Experts believe almond trees were one of the first trees cultivated by humans, starting some 4-5,000 years ago.
I. Appearance and Characteristics
Almond tree (Prunus dulcis) is a deciduous flowering tree grown for its pretty spring blossom and edible nuts. Almond trees form an upright and spreading head of branches, wreathed with masses of small pale pink or white flowers borne on the bare branches in late winter and early spring, before the leaves open.
Almond blossom flowers are bowl-shaped, borne singly or in pairs and are up to 5cm across. They’re usually pale pink, white, or deeper pink, depending on the variety. The dark green leaves, which open after the flowers, are lance-shaped with serrated edges. Large, rounded, green fruit form during summer and mature in autumn, forming velvety cases that enclose the edible almond nuts.
Correct siting is key to success with growing almonds in the UK – they do best in areas with mild winters and warm summers. An alternative to free-standing trees is to grow fan-trained almond plant against a south-facing wall or fence, which can retain more heat for the tree.
II. How to Grow and Care
Sunlight
At least six to eight hours of full sun daily are needed for the tree to bear the most flowers (and potentially nuts).
Temperature and Humidity
Almond trees have very specific temperature requirements. Between November and January, they need at least 300 chilling hours with temperatures below 45 degrees F, followed by a long frost-free period since almonds take seven to eight months to mature. The trees are highly vulnerable to severe cold and a spring frost is damaging to the flowers.
Summers must be hot with temperatures between 75 to 95 degrees F and low humidity. It is for these reasons that almond nut production in the United States occurs mainly in California.
Watering
Almond trees need a lot of water, especially during the nut development stage. Aim for about 3 to 4 inches of water per week, or enough to keep the soil moist. However, be mindful of overwatering, which may cause root rot.
Soil
The soil should have excellent drainage with a pH between 6.0 and 7.0. Sandy soil is best. Poorly drained or heavy clay soil is not suitable for growing almonds. Till the soil deeply before planting so that the roots can strike down deep.
Fertilizing
Fertilize your almond tree in spring with a balanced fertilizer. Apply this fertilizer along the drip line of the tree. For the amount to use, follow product label instructions.
Planting Instructions
Autumn is the ideal time to plant an almond tree, so the tree can start to establish well before the growing season starts in spring. Late winter to early spring is the next best time. However, container grown trees can be planted at any time of year.
- Dig a planting hole sufficiently wide for the roots to be spread out
- Ensure the top of the root ball is at soil level, firm in well, water in, and mulch the soil with compost or chipped bark to improve moisture retention and discourage weed growth
- Stake the tree with a short stake angled at 45 degrees and secured to the trunk using a tree tie
Pruning
Almond trees require minimal pruning. However, if you need to prune out dead, diseased, or damaged shoots, do so when the tree is dormant in winter. Thin the stems if necessary to create an open head of branches, as well as taking off any shoots that are growing on the trunk.
Propagation
Almond trees are propagated through grafting, which ensures that the tree has a solid rootstock and produces a high-quality crop. This is difficult for home gardeners to do, therefore it is best to purchase a tree from a reputable nursery. Some varieties are also protected by a trademark and may not be propagated in any form.
Overwintering
The best winter protection to give your tree is planting an almond variety that is winter-hardy in your growing zone and blooms late, which minimizes the risk of the blooms getting damaged by a late spring frost.
Pests and Diseases
Common Pests
Aphids: Small insects sucking sap from plants, causing yellowing and distortion of leaves, and producing sticky honeydew.
Scale Insects: Hard or soft-bodied insects feeding on sap, weakening plants, and excreting honeydew, encouraging sooty mold growth.
Caterpillars: Larvae feeding on foliage, leading to significant leaf loss, and potentially defoliating and weakening plants.
Tent Caterpillars: Social caterpillars construct silk tents in trees, heavily feeding on leaves and causing defoliation.
Japanese Beetles: Destructive pests feeding on a wide range of plants, skeletonizing leaves, and damaging flowers and fruits.
Navel Orangeworm: A significant pest, it burrows into the nut, affecting quality and yield. Proper sanitation and timely harvest are crucial for control.
Peach Twig Borer: Larvae bore into twigs and shoots, causing damage. Monitoring and targeted insecticide applications can manage their populations.
Mites: Various mite species can infest leaves, leading to discoloration and leaf drop. Miticides and natural predators can help control mite numbers.
Common Diseases
Brown Rot: This fungal disease affects the fruit, causing rot and reducing yield. Fungicide treatments and removing infected material can limit its spread.
Shot Hole Disease: Characterized by holes in the leaves, it’s caused by a fungus that can also affect fruit and twigs. Fungicide applications and good orchard hygiene are effective management strategies.
Anthracnose: This fungal infection targets leaves, blossoms, and fruits, creating lesions and causing “mummy nuts.” It can also produce toxins that kill twigs and branches. Management includes removing affected nuts and wood, using low-angle irrigation, and applying fungicides bi-weekly in wet conditions.
Phytophthora Crown Rot and Root Rot: This disease thrives in cool, wet conditions, attacking trees even without visible wounds. It leads to root decomposition and eventual tree death. Effective water management is crucial for prevention.
Almond Scab: Almond scab is favored by rain and high-angle sprinkler irrigation. It overwinters in twig lesions, causing defoliation, weakening the tree, and reducing yield.
Leaf Spot: Fungal or bacterial infections causing spots on leaves, leading to yellowing, browning, and potentially premature leaf drop.
Dieback: Progressive death of twigs and branches from the tip inward, often due to environmental stress or pathogens.
Powdery Mildew: Fungal disease manifesting as white, powdery coating on leaves and stems, stunting growth and distorting foliage.
Canker: Sunken, dead areas on branches or stems, resulting from fungal or bacterial infections, disrupting nutrient flow.
Black Knot: Fungal disease producing dark, swollen growths on branches, severely affecting tree health and aesthetics.
Verticillium Wilt: Soil-borne fungal disease causing wilting, yellowing, and death of leaves, often leading to plant demise.
Common Problems
Water Stress: Both overwatering and underwatering can stress almond trees, leading to poor nut development or disease. Implementing a consistent, appropriate irrigation schedule is vital.
Nutrient Deficiencies: Almond trees showing signs of nutrient deficiencies (e.g., yellowing leaves for nitrogen deficiency) require soil testing and appropriate fertilization to address imbalances.
Bacterial and Fungal Gummosis: Causing oozing of sap from the bark, it can be managed by improving tree vigor and removing infected parts.
III. Uses and Benefits
Almonds are incredibly versatile, used extensively in cooking for their nutty flavor in sweet and savory dishes. Almond milk and oil are popular in dairy-free and cosmetic products, respectively. The nuts are also a nutritious snack, rich in vitamin E, magnesium, and healthy fats. Additionally, almond wood is valued in woodworking for its durability and aesthetic appeal. Beyond nut production, almond trees are used in landscaping for their decorative flowers and shape.
IV. Harvesting and Storage
Almonds give you a clue as to when they are ready to be harvested: The hulls begin to split apart, revealing the familiar, light-colored shell. Do not wait too long after this splitting to harvest your almond nuts because the exposed shell is now fair game to both birds and insects.
The easiest way to get the almonds off the tree is to tap the branches with a pole. Lay a tarp down ahead of time to catch the almonds as they fall to make pick-up easier.
After gathering the almonds, they must be dried properly, or else they become moldy. Drying requires several steps:
- Remove the hulls.
- Spread the nuts out (with the shells still on), in a thin layer, across a surface conducive to drying. An ideal surface would be a table, the top of which has been replaced by a screen. Cover the shelled nuts with mesh to prevent birds from taking them, and cover them with a tarp when rain is expected.
- Check if the drying process is complete by sampling the “nuts.” Crack the shells of a few to find out whether the edible seeds within are hard or rubbery. If they are rubbery, then they are not completely dried out yet. If they are hard, then they are ready.
- When you have determined that your crop has dried out enough, bring the rest of the nuts, with their shells still on, indoors. Stored at room temperature, they will keep for eight months.
