Peaches
The peach (Prunus persica) is a tree native to China that bears a juicy fruit called a peach. It is a deciduous, belonging to the subfamily Prunoideae of the family Rosaceae. It is classified with the almond in the subgenus Amygdalus within the genus Prunus. Peaches are considered as stone fruits (drupes), along with cherries, plums and apricots.
The leaves are lanceolate. The flowers, which are produced in early spring before the leaves, are solitary or paired, pink, with five petals. The fruit is a drupe, with a single large seed encased in hard wood (called the "stone" or "pit"), yellow or whitish flesh, a delicate aroma, and a velvety skin (or smooth skin for nectarine varieties). The flesh is very delicate and easily bruised in some varieties, but is fairly firm in some commercial cultivars, especially when green. The seed is red, oval shaped and 1.5-2 cm thick.
The scientific name persica, derives from an early European belief that peaches were native to Persia (now Iran). The modern botanical consensus is that they originate in China, and were introduced to Persia and the Mediterranean region.
Cultivated peaches are divided into "freestone" and "clingstone" cultivars, depending on whether the flesh sticks to the stone or not; both kinds can have either white or yellow flesh. Peaches with white flesh typically are very sweet with little acidity, while yellow-fleshed peaches typically have an acidic tang coupled with sweetness, though this also varies greatly. Both colours often have some red on their skin. Low-acid white-fleshed peaches are the most popular kinds in China, Japan, and neighboring Asian countries, while Europeans and North Americans have historically favored the acidic, yellow-fleshed kinds.
Cultivation
Peach trees are the second most commonly cultivated fruit trees in the world after apple trees. They grow very well in a fairly limited range, since they have a chilling requirement that subtropical areas cannot satisfy, and they are not very cold-hardy. In addition, a lot of summer heat is required to mature the crop, with mean temperatures of the hottest month between 20 °C and 30 °C.
Another problematic issue in many peach-growing areas is spring frost. The blossoms can often be damaged or killed by freezes - typically, if temperatures drop below about 4 ºC, most blossoms will be killed. However, if the blooms are not fully open, they can tolerate a couple degrees colder.
Important historical peach-producing areas are China and Iran, France, the Mediterranean states like Italy, Spain and Greece. More recently, the U.S. (Alabama, California, Colorado, Delaware, Georgia, Maryland, Michigan, New Jersey, Oregon, South Carolina, Texas, Utah, Virginia, Washington, West Virginia, Puerto Rico), Canada (southern Ontario and British Columbia), and Australia (the Riverland region) have also become important.
Diseases
Most peach trees sold by nurseries are grafted cultivars. The trees are prone to a disease called leaf curl, which usually does not directly affect the fruit but does reduce the crop yield by partially defoliating the tree. The fruit is very susceptible to brown rot.
Growing Conditions
Peaches should be located in full sun, and with good air flow. This allows cold air to flow away on frosty nights and keeps the area cool in summer. For optimum growth, peach trees require a constant supply of water. This should be increased shortly before the harvest. The best tasting fruit is produced when the peach is watered throughout the season. Peaches have a high nutrient requirement, needing more nitrogen than most other fruit trees. If the full amount of peaches is left, they will be under-sized and lacking in sugar and flavour. In dry conditions, extra watering is important. The fruit should be thinned when they have reached 2 cm in diameter, usually about 2 months after flowering. Fresh fruit are best consumed on the day of picking, and do not keep well. They are best eaten when the fruit is slightly soft, having aroma, and heated by the sun.
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