Tree of the Week: The apple is among the oldest of fruit trees
Apple -- Malus domestica
Any tree that has "domestica" in its name has been domesticated for a long time. The apple is one of the oldest and most widely cultivated fruit trees on Earth. Its ancestors -- M. sieversii and other species -- originated in Central Asia, including Kazakhstan. Trading along the Silk Road from the Black Sea to western China probably led to hundreds of accidental and deliberate cross-hybridizations since 6500 BC.
Today there are more than 7,500 varieties of apples. Charred remains have been found in Swiss Stone Age villages. Alexander the Great brought dwarf apples back to Macedonia in the fourth century BC. Colonists brought apple trees to this country in the 1600s.
Because planted apple seeds create unpredictable outcomes, and desirable varieties often have some less acceptable qualities, good clones are made to grow on selected rootstocks of different apples through budding or grafting. The rootstock may dwarf the tree, make it disease-resistant or add other desired qualities. Natural spur types and columnar trees are also options. Occasionally a tree will spontaneously create a new variety, called a bud sport, on a branch.
A standard apple tree grows to a handsome, long-lived, deciduous, twiggy tree, some 20 feet tall by 25 wide, with an initially smooth, eventually rough brown bark. But the range of available rootstocks produces a choice of sizes, down to small dwarfs. In addition, distinct ways to prune, such as pyramid or open vase, create different shapes. Today’s preference is for lower-growing trees. Training to a strong framework should start at an early age. Oval leaves are up to 5 by 2 inches in size, with a pointed tip, toothed edges and downy underside. In mild winter areas, trees often hold on to their leaves past winter. Beautiful five-petaled pink blossoms, up to 1.5 inches long, fade to white; they grow on long-lived short fruit spurs. Fruit is 2 to 3.5 inches big, and contains five carpels or seed bags, each holding one to three black or brown seeds. Different rootstocks may do best on different soils; the trees want full sun, no crowding and periodic deep soaking. Codling moth, apple scab, mildew and aphids can be problems, but are not serious enough to prevent growing by backyard enthusiasts.
Apples need pollination from a suitable other variety nearby. They do best in a temperate climate and want enough hours below 65 degrees (winter chill) for proper fruit set. Here in the Southland we use low-chill varieties.
-- Pieter Severynen
Photo: An apple tree in Tehachapi, Calif., pruned in an open vase shape. Credit: Pieter Severynen