Almond tree: identification, where it grows and how to care for one

At a glance

What an almond tree looks like

An almond looks much like a peach tree that blooms at the same time or a little earlier. The Missouri Botanical Garden and the RHS describe a dense, rounded to upright-spreading deciduous tree (or large multi-stemmed shrub) with these features:

• Flowers: fragrant, five-petaled, light pink to white, borne singly or in pairs on bare branches in late winter or early spring, before the leaves. In California's Central Valley, the main commercial cultivar blooms around the third week of February, per Utah State University Extension.
• Leaves: lance-shaped to oblong-lance-shaped, up to about 5 inches long, with toothed edges, very similar to peach leaves. Fall color is a dull yellow-green.
• Fruit: an oblong, fuzzy, gray-green drupe that looks like an unripe peach, but the outer flesh (the hull) stays thin and leathery. About 7–8 months after bloom the hull splits to expose the shell, which holds the edible seed: the almond.
• Form: flowers are carried on short spurs and short side shoots; orchard trees are usually pruned to an open vase.

Look-alikes

Where almond trees grow, and can you grow them outside California?

Winter hardiness is rarely the problem. Per Utah State University Extension, temperatures below −10°F can damage fruit buds in winter and below −20°F damage stems and branches. The bigger problem is bloom time. Almonds flower with or slightly before peaches, and temperatures below 28°F during or after flowering damage the flowers and prevent a crop. A tree can live for decades and still lose many crops to late frost.

The second limit is season length and humidity. The Missouri Botanical Garden notes almonds do best in hot, dry, low-humidity places with a long growing season, such as California's interior valleys. Rain at bloom and hull split favors diseases (see Pests and problems below).

So yes, you can grow almonds outside California. Plant expecting a good crop in some years, not every year. A site with good air drainage, never a low spot where frost settles, improves the odds.

Almond varieties and pollination

Most almond cultivars are self-incompatible: Utah State University Extension notes their flowers need pollen from a different cultivar (or a peach) that blooms at the same time, carried by bees. For a backyard you have two options: one self-fruitful cultivar, or two compatible cultivars.

Even self-fertile cultivars set more nuts when bees visit: UC Davis researchers found honey bee pollination significantly improved nut set and yield in 'Independence'. Protect bees during bloom by not spraying insecticides while flowers are open. For how cross-pollination works across fruit trees, see fruit tree pollination pairs.

Buy a grafted, named cultivar rather than a seedling so you know what kind of nut you'll get.

How to plant an almond tree

1. Time it right. Plant bare-root trees in late winter while dormant, or container trees in early spring. The technique is in how to plant bare-root trees.
2. Choose the site for frost and drainage. Pick full sun on a gentle slope or other spot where cold air drains away. Avoid low areas, heavy clay and any soil that stays soggy after rain.
3. Give it room. Utah State University Extension says a mature almond occupies roughly 20 by 20 feet, so space trees about 20 feet apart. Keep two cultivars that need to cross-pollinate close enough that bees work both.
4. Plant at nursery depth with the graft union above the soil line. Water deeply and mulch 2–3 inches deep, keeping mulch off the trunk.
5. Head the young tree at about 30–36 inches above the soil at planting, as Utah State recommends, to start a low framework (see Pruning).

How much water does an almond tree need?

It depends on your climate more than on the tree. Almonds are grown in dry-summer regions, but nut size and kernel fill depend on adequate water from spring through midsummer.

• How to water: Utah State University Extension advises watering long enough to wet the soil about 1 foot deep, then letting the soil dry for several days (depending on weather) before watering again. Deep, infrequent watering beats frequent light sprinkles.
• Humid East: rainfall usually covers most needs. Water deeply during extended dry spells in late spring and summer, and focus on drainage. Wet soil does more harm than mild drought.
• Young trees: keep the root zone evenly moist for the first two seasons; watering newly planted trees explains how to check moisture.
• At hull split: UC IPM says reducing irrigation at the onset of hull split, and avoiding standing water then, greatly reduces hull rot.

Fertilizing and pruning

Fertilizer: almonds need only moderate nitrogen. UC IPM lists managing tree vigor through irrigation and nitrogen as the most effective hull rot control and warns against excess nitrogen. Start with a soil test, feed in early spring if growth is weak, and avoid late-summer feeding that keeps the tree growing into fall. When and how to fertilize trees covers the basics.

Pruning: train almonds like peaches, to an open center (vase) with a few main scaffold limbs, so light and air reach the interior. Utah State University Extension recommends heading the tree at 30–36 inches at planting and keeping a straight, branch-free trunk for the first 30–40 inches. Prune young trees in the dormant season to build that framework. On bearing trees, prune lightly: flowers are borne on spurs and short side shoots, so heavy cutting reduces the crop. Utah State also advises not letting trees set nuts for the first 3 years after planting. Prune in dry weather to limit infection of fresh cuts. The method is the same as in how to prune fruit trees.

Harvesting almonds

Almonds are ready in late summer to fall, when the hulls have split open and the nuts have dried on the tree. Utah State University Extension says to leave almonds to mature and dry on the tree; in California, 'Nonpareil' matures at the end of August and 'Mission' 40–60 days later.

1. Spread a tarp under the tree and shake the limbs or knock them gently with a padded pole.
2. Pull off the hulls and spread the in-shell nuts in a single layer in a dry, airy, shaded place until fully dry.
3. Store dry nuts in airtight containers in a cool place; Utah State notes airtight storage slows oxidation of the oils.

Harvest promptly. Birds, squirrels and insects work open hulls quickly, and nuts left on the tree through fall rains are prone to mold.

Bitter kernels: the almonds sold to eat are sweet types. Some trees sold for cold climates, such as 'Hall's Hardy', produce bitter kernels, per Utah State University Extension. Check the cultivar description before buying if you want edible nuts.

Pests and problems

Almonds share most of their problems with peaches. UC IPM's almond guidelines cover the California side, and Utah State University Extension lists the same insects and diseases that affect peaches and apricots.

• Frost at bloom: the most common cause of no crop outside California. Site selection is the main fix.
• Brown rot blossom blight: blossoms and young spurs collapse; UC IPM says infection is favored by rainy weather during bloom.
• Shot hole disease (also called coryneum blight): tiny reddish specks on leaves become spots with tan centers and purplish margins, and spots on young leaves fall out, leaving holes. UC IPM notes it needs prolonged wetness from rain or sprinklers.
• Hull rot: fungi infect splitting hulls and kill the spur and shoot; worse with heavy irrigation and excess nitrogen at hull split (UC IPM).
• Borers: peach twig borer and greater peach tree borer both attack almonds. Look for gummy ooze mixed with sawdust at the trunk base, and see peach tree borer.
• Mites: European red mite and spider mites can bronze leaves in hot, dry weather.
• Phytophthora root and crown rot: decline in wet, poorly drained soil. Prevention through site choice is the only reliable control.

Common mistakes

Frequently asked

Can you grow almonds outside California?

Yes, in USDA zones 7–9, but crops are less reliable. Utah State University Extension notes that temperatures below 28°F during or after bloom kill the flowers, and the Missouri Botanical Garden says trees in St. Louis may survive but generally don't produce nuts because of the short season and late frosts. Choose a frost-free slope and a self-fruitful cultivar.

Is an almond a tree nut?

For food-allergy purposes, yes: the FDA lists almonds as a tree nut. Botanically, the almond is the seed inside the pit of a drupe, the same fruit type as a peach. The difference is that the outer flesh stays thin and leathery and splits open instead of becoming juicy.

How long does it take an almond tree to produce nuts?

Utah State University Extension says not to expect a harvest for 4–6 years after planting, and advises against letting the tree set nuts during its first 3 years. A late frost at bloom can wipe out a year's crop on a tree of any age.

Do you need two almond trees to get nuts?

Usually, yes. Most almond cultivars need pollen from a different compatible cultivar that blooms at the same time. Self-fruitful cultivars such as 'All-in-One' and 'Independence' can bear alone, though UC Davis research found bee pollination still increased nut set in 'Independence'.

How big does an almond tree get?

The Missouri Botanical Garden says almonds typically grow 10–15 feet tall and wide, less often to 30 feet; the RHS gives 4–8 meters. Utah State University Extension says a mature tree can occupy about 20 by 20 feet. 'All-in-One' is somewhat dwarfing.

When do almond trees bloom?

Almonds bloom in late winter to early spring, before the leaves appear and at the same time as or slightly before peaches. In California's Central Valley, 'Nonpareil' blooms around the third week of February. Early bloom is why frost, not winter cold, is the main limit on where almonds crop well.

Sources

1. Almonds in the Home Garden, Utah State University Extension
2. Prunus dulcis, Missouri Botanical Garden Plant Finder
3. Prunus dulcis (almond), Royal Horticultural Society
4. Almond: Pest Management Guidelines, UC Statewide IPM Program
5. Hull Rot (Almond), UC Statewide IPM Program
6. Shot Hole (Almond), UC Statewide IPM Program
7. Brown Rot Blossom Blight (Almond), UC Statewide IPM Program
8. Researchers Analyze a Self-Fertile Almond Variety, UC Davis Department of Entomology and Nematology
9. Food Allergies: What You Need to Know, U.S. Food and Drug Administration

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