A Day in the Arboretum
by Alfredo Chiri
ALMOND - Prunus dulcis - Rosacea
1) Fullerton Arboretum and planted in 1972 (r.f.-09)
2) cv "Allinone": Fullerton Arboretum and planted in 1984 (orch-04)
(3) Fullerton Arboretum and planted in 1972 (r.f.-09)
The botanical name of the almond was changed in 1980 to Prunus dulcis [Mill.]; formerly P. amygdalus or P. communis.
The almond originated in the hot dry climate of Iran and was spread along the shores of northern Africa by Egyptians, Greeks, and Romans. Spanish Padres who settled the Mission at Santa Barbara brought the almond to California in the 1700s. Larger plantings did not occur until the 1800s.
It is a small to medium-sized tree, 10 to 25 feet tall, with gray bark with light colored glabrous (smooth) branchlets. Leaves are linear and
firm, oblong-lanceolate, 3-4 inches long, shining above, lighter beneath like the peach trees. The tree produces "spurs" or short lateral branches which bear most of the fruit; they grow only an inch or two each year.
Almond flowers are lighter pink to white and nearly identical to the peach flowers in structure. Flowering in old wood gradually declines;
hence older limbs become unfruitful and are pruned out. Most cultivars with highly self-unfruitful limbs must have good bee activity and
pollinizers interplanted with the main crop. Pollinizers are planted in separated rows. Since pollination is so critical, usually 2 pollinizers
are used, one blooming slightly ahead but overlapping the flowering season and another one slightly after.
The fruit starts as a drupe and ends up as a nut. The fruit is large, 1 ½ inch, and more or less long, oblong-ovoid and compressed, the flesh hard and splitting at maturity, disclosing the shallow pitted stone. The variety grown in the arboretum is primarily a sweet-kerneled form.
Fruiting begins in 3-4 year old trees, with maximal production by 6-7 years. Unlike its cousin, the short-lived peach, almond trees can produce for 50+ years. Trees are harvested by shake-and-catch method. Nuts are then wind-rowed and left for a period of time to dry further.
Almonds require deep, well-drained, loamy soils with pH 6-7. The almond tree is a true Mediterranean fruit crop, requiring mild winters and long, rain-less, hot summers with low humidity. The tree requires only 300-500 chill units for proper bud break; they survive single digits and teens Fahrenheit. Almonds bloom in February in California.
Propagation is by T-or chip-budded onto a variety of seedling rootstocks, primarily peach seedlings. Trees are planted 22-30 feet apart in square or rectangular arrangements with separate rows of pollinizers.