Almond trees (Prunus dulcis) come in bitter and sweet varieties. Sweet almonds can be eaten raw or used in recipes. Bitter almonds must be processed to remove the toxic substance that causes the bitter taste, and are mostly grown commercially. Almond trees have similar care needs to peach trees and can be grown in U.S. Department of Agriculture plant hardiness zones 7 through 9. They require at least two trees be planted for proper pollination.
Flood the tree with water once per week during the first year after planting. Decrease watering to every two to four weeks in subsequent years. Adjust watering as necessary to avoid drowning the roots or allowing the soil to dry out.
Almond trees need full sun, at least 6 hours a day, but more sun will mean better blooms. Paint the south side of the trunk and large branches with whitewash to protect the tree from sunscald if the sun is too hot.
Fertilize twice a year in the spring, before new growth appears, and again in the early fall. Use 1 cup of 10-10-10 fertilizer per year of tree age, with a maximum of 10 cups, in the spring application. Use 1 cup of calcium nitrate per year of tree age, with a maximum of 4 cups, in the fall application. Do not apply in the fall if there were no nuts that year.
Plant almond trees in well-draining soil with at least 5 feet of topsoil. The soil can be mounded to create the proper depth. Till several inches of compost into the soil before digging. Almond trees will grow in most soil types and can be planted in sandy, loamy or clay soils. The trees will grow best in soil with a pH of around 6.5, although they will tolerate acidic, neutral and alkaline pH levels. Dig the planting hole as deep and twice as wide as the roots.
Prune the tree each year in late winter when it is dormant. Remove dead limbs anytime throughout the year. Thin out branches that cross over other branches, grow vertically, grow inward or have less than a 45-degree crotch angle with the trunk. Low-hanging branches can also be removed. Almond trees reach about 15 feet in height. Cut back limbs to a lateral shoot or a bud to maintain the canopy shape and keep the tree size.
Although no specific mention has been seen for this species, it belongs to a genus where most, if not all members of the genus produce hydrogen cyanide, a poison that gives almonds their characteristic flavour. This toxin is found mainly in the leaves and seed and is readily detected by its bitter taste. It is usually present in too small a quantity to do any harm but any very bitter seed or fruit should not be eaten. In small quantities, hydrogen cyanide has been shown to stimulate respiration and improve digestion, it is also claimed to be of benefit in the treatment of cancer. In excess, however, it can cause respiratory failure and even death.
