The common apple, with beginnings millennia ago, remains among the most important fruit tree crops across the globe. Folklore accompanied the apple, such as William Tell shooting a fruit from atop his son's head, to Isaac Newton discovering gravity thanks to a falling apple, to America's Johnny (Chapman) Appleseed planting trees across the new nation. Today's common apple is a highly selected, genetically manipulated plant not necessarily resembling ancestral trees.
There are about 35 species of wild apples, all native to the woodlands or shrub-thickets of Europe, Asia or North America. The common apple or modern edible apple has a muddy past, but botanists tend to believe its origins center in western Asia.
The apple is a member of the rose family, Rosaceae. This plant family contains many other important fruit crops such as peaches, plums, cherries, apricots and pears. Apples segregate from all these fruits except pears into a subfamily known once as Maloideae but today as Pomoideae. All apples are grouped into the genus Malus, and the common apple is known botanically as Malus x domestica.
Apples were eaten across Eurasia since prehistoric times. Domestication of apples likely occurred early on, since the Romans made reference to at least 22 different apple varieties, according to "Economic Botany: Plants in Our World." This textbook further reveals that by 1670 more than 50 apple varieties were growing in northern Italy. In the United States, historians believe the first apples were grown in Massachusetts on the Charlestown Peninsula in the 1620s. Washington State began growing commercially irrigated crops of common apples in the 20th century. Today, nearly 7,000 horticultural varieties of apples exist worldwide, including those with names like 'Jonathan', 'Red Delicious', 'Fuji' and 'Granny Smith'.
In the wild setting centuries ago, the first common apple trees grew into round or oval-canopied deciduous plants maturing to about 30 to 35 feet tall, and about 20 feet wide. Today's varieties with complex lineages often grow grafted upon disease-resistant dwarfing rootstocks that make the common apple today mature to 6 to 20 feet. The fragrant white or pink-blushed flowers bear five petals and are pollinated by insects in spring just before or as the leaves emerge. The green leaves look like tapering ovals with tiny teeth on their edges and blush shades of yellow, orange or red in autumn. The apple fruits take 120 to 150 days to ripen. Fruit skins range from red and orange-red to mottled gold, green and pink-red. The seeds in the apple core are found in any of five chambers and contain trace amounts of cyanide poison.
The common apple prospers in full sun in deep, fertile, loamy soils that are moist but well-draining. Avoid alkaline soils (pH above 7.5) and nutrient-poor, sandy ones. Needing a pronounced cold winter dormancy in order to produce flower buds the following spring, the apple generally grows between 30 and 70 degree latitudes around the world. This equates roughly to USDA Hardiness Zones 3 through 7, although each variety demonstrates different survivability to winter cold based on its genetic makeup and lineage.