For more than 200 years the Peach was believed to have originated in Persia and the scientific name, Prunus persica, indicates a Persian origin. However, in tracking down historical references to the Peach, scientists found that at about 1500 B.C. it was unknown in Persia and western India although it is mentioned in Chinese literature more than 500 years earlier. Thus, China is now the accepted origin of the Peach and its move west-ward is traced first to Greece and then to the temperate areas of Europe.
Peaches were brought to North America the Spanish, French and English settlers. Perhaps the fruit was first brought to Mexico by the Spaniards, who also brought them to Fla. in 1565, while English and French settlers brought the seeds to eastern U.S. The native Indians carried this fruit far inland and it eventually reached the West Coast. Today the Peach is of commercial importance in Africa, South America, Europe, Asia and North America.
Peach Growing in the United States
Peaches are being grown in at least 38 states of the U.S. The areas best suited to peach growing are the West Coast states, the East Coast states from Fla. to Mass., and the area south and east of the Great Lakes. The south-western slopes of the Rocky Mountains in Colo. are an important peach-producing area also.
Since the Peach is not a cold-hardy fruit, its areas of growth are limited by minimum winter temperatures. A temperature drop to —10° F. will usually kill many fruit buds and a temperature of — 50° F. will often kill trees. The amount of damage following cold temperatures is influenced to a great extent by the preceding temperatures. Warm weather for several days preceding a quick drop to below zero causes most cold damage. This is especially true after the tree has completed its rest period. In southern areas the bark of trees can be severely injured when day temperatures of 70° F. are followed by a drop to 18° F. above zero at night.
Like all deciduous plants, peach trees require a rest period between the time when the leaves fall and the flowers appear the following spring. Peach varieties differ considerably in their cold requirements for dormancy, the required time ranging from 600 to 1200 hours of 45° F. or below to complete the rest period. Varieties that require the minimum number of cold hours to complete a rest period have been developed so that peaches may be grown in warmer, near sub-tropical, climates. Such varieties are needed for Fla., south Tex. and southern Calif.
The Peach Tree
The Peach is not as long-lived as the Apple. Although some may live to be 35 years old, most peach trees do not live much beyond 50 years and in some areas to years is the life expectancy. The young tree grows vigorously for the first 3 years. During the first year, a well-grown tree will grow from 500 to 1500 total inches of new growth depending upon weather and general culture. In its second season of growth a few fruits will be produced on the tree, but it is best to remove these fruits and so permit the tree to make vegetative growth and to attain good size for early future production. The Peach produces fruit mainly on terminal, year-old shoots, which, for best fruiting, should be about 12 in. long. Fruit buds develop all along this 12-in. shoot and there may be as many as 30 of these. The peach tree that is growing in its third season may produce 75 to 150 peaches. A simple rule of thumb for production is 1 bushel in the third year, 2 bushels in the fourth year, and so on, increasing production by 1 bushel each year until 6 bushels are produced in the eighth year. More or less may be produced per tree, depending upon weather, culture, variety and tree size.
How the Peach Tree is Produced
Peach pits are planted and seedling trees grow from these pits. During June in southern states these seedling trees are budded to known varieties. This is necessary since seedling trees will not produce fruit similar to the parent variety. Usually the fruit of a seedling tree is much inferior to the parent tree. Buds inserted into the seedling tree during June begin to grow within a few weeks and the seedling growth above the bud is removed. The resulting growth from the inserted bud becomes a tree of a known variety and this tree is ready to plant in the garden that same fall or the following year. In northern areas, budding is done in Aug. but, though union of the bud with the stock or seedling occurs, the bud remains dormant until the spring of the following year.
Peach Tree Size Control
In most home gardens, the standard size peach tree is quite satisfactory. It can be maintained at a height of about 8-10 ft. and a width of 12-15 ft. by careful pruning. A very limited number of peach trees are available on dwarfing rootstocks. The use of dwarfing stocks has not been so successful or as widely used with the Peach as with the Apple and Pear.
There are a few natural dwarf peach varieties. One that has had some success is called ‘Bonanza’. A natural dwarf peach tree is one with shorter nodes and more leaves per length of growth than the standard tree, even though it is growing on standard seedling roots. It is similar to the spur type apple tree where the terminal growth is short and the tree is smaller than standard. The true dwarf peach tree produces some fruit but because of its small size, the peaches are fewer in number.
Peach General Culture
To grow peach trees successfully in the home garden, several cultural procedures must be followed. Beginning with proper planting, trees must be fertilized, cultivated, sprayed for insect and disease control and pruned annually. Fruit thinning and limb propping are often necessary as the tree beings to produce full crops of fruit. During drought seasons and in arid regions, irrigation is necessary.
Peach Tree Planting
Spring planting is best and this should be accomplished before growth begins. Dig a hole large enough to accommodate the entire root system without crowding. It should be deep enough to allow the tree to be planted at about the same depth of soil in which it grew in the nursery. While digging, keep the topsoil separate from the subsoil. Place some of the topsoil in the bottom of the hole and spread the roots over it, then sift more topsoil around the roots. If you can get rotted manure or compost, mix it with equal parts of topsoil and fill the hole with the mixture. If the soil is extremely acid, mix 1 or 2 lbs. of limestone with the soil in the hole. Soils along the eastern seaboard are naturally acid. Those in western regions are alkaline and do not require additional limestone. Do not put fertilizer in the hole at planting time. Pack the soil firmly around the roots with your feet.
After planting, thoroughly water the soil around the tree. Keep the soil moist during spring and through the first summer. A slight depression about 2 ft. in dia. left around the base of the tree will help to keep water in the root area. In the fall, mound the soil slightly around the tree to reduce ice accumulation and possible injury to the bark on the trunk.
Full sunshine is essential to good tree growth and production. Trees will grow spindly and fruit production will be slight and of poor quality if grown in a shaded area.
Trees will not tolerate a wet soil. The soil must be sufficiently well drained so that water does not stand on the surface or saturate the root area for days following a heavy rain. Peach trees die quickly from excessive water around the roots.
Peach Tree Fertilization
A nitrogenous material such as ammonium nitrate may be used, or a complete fertilizer; a second application may be needed about 6 weeks later to maintain good vigor. Excessive growth should be avoided because this results in a poor tree framework. An excessively vigorous tree produces an upright growth with narrow, weak crotches where limbs join the trunk.
The amount of fertilizer should be increased each year until the tree receives 1 lb. of actual nitrogen. This may be sufficient to maintain vigor and production, but if the soil is poor, more fertilizer will be needed. On sandy soil, peach trees can utilize 1 lb. of actual nitrogen per year. The growth of the tree and the color of the foliage are good indicators of tree vigor. A bearing tree should make terminal growth that is about 12 in. long and the leaves should have a healthy green color. Light green or yellowish leaves indicate a lack of sufficient nitrogen either because an insufficient amount of fertilizer was applied, because of excessively dry soil or because there is injury to the tree from borers or other trunk or root damage.
Peach Tree Cultivation
Peach trees grow best when the soil beneath the tree is cultivated and kept weed-free. Mulching the soil under the tree is an excellent practice and can be done instead of cultivation. The mulch must be thick enough to prevent weed and grass growth. Straw, wood chips and lawn clippings make excellent mulching materials. An area of about 2 ft. around the trunk should be kept free of mulch to reduce the possibility of mouse injury to the roots and trunk. One should watch for mice runs under the mulch and trap the mice if they are present.
Peach Tree Irrigation
During dry seasons and in arid regions, peach trees must be irrigated. A bearing tree requires about 3 in. of rain per month during the growing season and, if this does not come as rain, an equal amount of water must be applied to the soil. The best method of watering a peach tree in the garden is to place a hose at the base of the tree and to let water trickle slowly for an hour or more. A depression in the soil around the base of the tree will prevent water loss. The period when the tree needs water most critically is during the month prior to fruit ripening. A shortage of water at this time will result in a reduction of fruit size. Drought in early spring will seriously reduce terminal growth and fruit-bud formation for the next year, so water should be applied at any time when the moisture in the soil is low.
A bearing peach tree usually produces more blossoms and “sets” more peaches than it can grow to large size and good dessert quality, so the removal of some fruit is necessary. Killing of buds by winter cold or by spring frosts can reduce the crop so that little or no thinning is necessary. A mature peach tree may have 25,000 or more blossoms. This same tree can ripen to good size and quality about 1200 large peaches (6 bushels). Thus, between the time of blossoming and the harvest of the mature fruit, about 95% of the blossoms and young fruit must either drop or be removed by hand. Many of the blossoms drop soon after the petals fall, either because they were not pollinated or because the tree could not supply the tiny fruits with water and nutrients. For this reason, also, a great many more tiny fruits will fall about 2 weeks after bloom.
About a month after bloom, another natural drop of fruit occurs and this is a final attempt by the tree to reduce the load of fruit. The tree will carry most of the remaining peaches to maturity. If there are more than 1500 peaches on the average-sized mature tree, some must be removed by hand or they will be small and of inferior dessert quality. To determine how much fruit to remove, one can take a small section of the tree and count the peaches. This count will provide a rough estimate of the total number of peaches and will indicate whether further reduction is necessary. Usually if peaches are removed so that those remaining are 6-8 in apart, the thinning is sufficient.
The main reason for thinning is to reduce the number of fruits per leaves. It has been shown through research that about 35 leaves are required to ripen 1 large peach of good dessert quality.
Thinning should be completed as soon as the last natural drop of fruit occurs for those varieties ripening in midseason and later. For early ripening varieties, the thinning should be completed before the last natural drop, or about 3 weeks before ripening. This is sometimes difficult because the fruit is quite small and one is not quite sure as to how much fruit will still drop naturally. It is absolutely necessary to thin early ripening varieties early to attain peaches of good size. A peach that is 2 in. in dia. is quite acceptable and there are about 300 in a bushel. A 2.1 in. peach will average about 200 in a bushel.
Peaches ripen rapidly when temperatures are above 80-85° F. As they begin to ripen, they should be harvested every 2 or 3 days, depending upon the temperature. High night temperatures speed the ripening. Of the early varieties, the first few fruits to ripen will have a split pit. This is a normal characteristic. Often mold will be present on the seed. This is also normal and the peach flesh is healthy and good to eat even though the pit is molded. Peaches can be ripened fully on the tree and eaten immediately, or they may be harvested in a firm-ripe condition and held at room temperature for about 3 days. They will then have ripened to excellent dessert quality. Peaches harvested when green and immature may soften, but the dessert quality will be very poor.
Peaches can be held in commercial cold storage at 31°-32° F. for a month or slightly longer. In the home refrigerator, which is maintained at about 40° F., they will hold for a few days in excellent condition if they are ripe or firm-ripe when placed in the refrigerator. Prolonged holding at 40°-50° F. results in internal breakdown and poor flavor. Firm-ripe peaches will soften and ripen slowly while in the refrigerator, but will require about a day or two at room temperature to develop good quality. Ripening proceeds half as fast at 60° F. as at 70-80° F, and only half as fast at 50° as at 60° F.
Peach Tree Pruning
The year-old peach tree will arrive from the nursery as a branched whip. It should be cutback to about 30-36 in. above the ground. Usually the side branches are weak and too small for framework branches. Cut these branches back to spurs, leaving 2-3 buds on each.
After the tree’s first season, remove all side branches that form a narrow angle with the trunk (less than 45°). Remove 1 of any 2 limbs of equal size that tend to divide the tree into a “V.” Remove suckers or strong branches that fill and shade the center of the tree. To keep the tree well balanced, cut back the stronger frame-work branches slightly. A central leader similar to that of an apple tree may be developed, but an open-center tree with 3 main framework branches is preferred.
After the second season, prune to develop an open-center, spreading, bowl-shaped tree. Remove any large limb that tends to grow up through the center, or across the center. Remove large suckers growing straight up in the center. Retain most of the other growth through-out the tree. As with the 1-year tree, remove limbs with narrow angles and branches of equal size that form a weak crotch.
A peach tree grown well for 2 years will have a trunk 4-6 in. in circumference and a good supply of fruit buds. Moderate and careful pruning at the end of the second season can result in production of as much as a bushel of peaches during the third summer. Severe pruning at the end of the second season will reduce, and may eliminate, the third summer crop.
After the third year, the peach tree should produce annual crops of fruit. Pruning is much the same throughout the first 4-5 years. After that time, somewhat more severe pruning may be desirable to keep the tree within bounds and maintain plenty of strong, healthy, fruiting wood.
Peaches are produced on wood that grew the previous season. The open-center or bowl-shaped tree with a well-rounded base and a wide-spreading top is recommended and generally grown throughout the country. Trees of this type have a larger bearing surface near the ground than do other types. They also have good fruiting wood throughout the center. The height of the tree should be kept to a maximum of 10 ft., the exact height depending on variety, soil, and general culture. It is possible, by careful pruning, to hold the peach tree to a height of about 7 ft. and still maintain good production.
Peach Tree Pollination
There is no serious problem in regard to cross-pollination with the Peach because most varieties are self-fruitful. There are a few varieties that are not, and if these are selected, one must provide another self-fruitful variety for pollination. The ‘J. H. Hale’ is one of the self-unfruitful varieties.
Peach Pest Control
The control of major insects and diseases by spraying and general sanitation is necessary to produce fine fruit and to maintain vigorous trees. Spray schedules are available for home trees and single-package mixtures containing insecticides and fungicides make the job quite simple and safe. To be successful in pest control, the proper materials must be used, applied at the correct time, and the tree must be thoroughly covered.
During the first 2 years in the life of the tree the spray program is not a complete one because there is no fruit. Leaf-chewing insects and borers are the main problems. After fruit production begins, one must follow a full spray program. Some of the most common insects of the peach fruit are plum curculio and oriental fruit worm. The most destructive disease attacking the fruit is fungus and brown rot. Borers can be a very serious threat to the vigor and life of the peach tree. The base of the trunk area should be checked several times annually for signs of borers. A jellylike substance will appear at the soil level if borers are present and they must be destroyed. A soft piece of wire forced into the holes will kill them.
In addition to spraying, certain sanitary practices will help, especially in the reduction and control of diseases. All dropped fruit should be gathered and removed from the area because this is a source of brown rot. Peaches that become infested with brown rot sometimes hang on the tree to shrivel and dry. These are also a source of infection and should be removed during the pruning.