The peach (Prunus persica) is a species of Prunus native to China that bears an edible juicy fruit also called a peach. It is a deciduous tree growing to 5–10 m tall, belonging to the subfamily Prunoideae of the family Rosaceae.
Peach trees 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. The trees themselves can usually tolerate temperatures to around −26 °C to −30 °C, although the following season’s flower buds are usually killed at these temperatures, leading to no crop that summer.
Flower bud kill begins to occur at temperatures between −15 °C and −25 °C depending on the cultivar (some are more cold-tolerant than others) and the timing of the cold, with the buds becoming less cold tolerant in late winter. Certain cultivars are more tender and others can tolerate a few degrees colder. 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 trees tend to flower fairly early in spring.
The flowers can often be damaged or killed by freezes; typically, if temperatures drop below about −4 °C, most flowers will be killed. However, if the flowers are not fully open, they can tolerate a couple of degrees colder.
A nectarine is a cultivar group of peach that has a smooth, fuzzless skin. Though fuzzy peaches and nectarines are commercially regarded as different fruits, with nectarines often erroneously believed to be a crossbreed between peaches and plums, or a “peach with a plum skin”, they belong to the same species as peaches. Several genetic studies have concluded in fact that nectarines are created due to a recessive gene, whereas a fuzzy peach skin is dominant.
Nectarines have arisen many times from peach trees, often as bud sports.
As with peaches, nectarines can be white or yellow, and clingstone or freestone. On average, nectarines are slightly smaller and sweeter than peaches, but with much overlap. The lack of skin fuzz can make nectarine skins appear more reddish than those of peaches, contributing to the fruit’s plum-like appearance. The lack of down on the skin also means their skin is more easily bruised than peaches.